_:b419878211 . _:b419878181 . _:b6530263 "In fission yeast, the SIN pathway triggers the initiation of contraction of a centrally placed actomyosin ring and formation of the division septum (Krapp et al., >>2004<<). In contrast, the MEN pathway maintains the cytoplasmic localization cell division cycle (Cdc) 14 phosphatase, preventing its sequestration in the nucleolus during late anaphase and allowing Cdc14 to antagonize CDK phosphorylation of key" . _:b419878210 . . _:b419878221 . . . _:b419878193 . _:b419878220 . . _:b6530338 . _:b419878223 . . _:b419878222 . . _:b419878217 . _:b6530293 "In budding and fission yeast, Mob1 facilitates mitotic exit and cytokinesis by acting as a regulatory subunit for Dbf2/Sid2 kinase (Komarnitsky et al., 1998; Luca et al., 2001; Devroe et al., 2004; Hou et al., >>2004<<). Mob1 and its effector kinase localize first to the spindle pole bodies until anaphase onset, at which time the complex relocalizes to the bud neck/actin ring (Frenz et al., 2000; Salimova et al., 2000; Luca et al., 2001; Yoshida and" . _:b419878216 . . _:b6530353 "However, most reports in the literature ascribe roles for MEN/SIN orthologues in tumor suppressor pathways regulating organ size and cell proliferation (Pan, >>2007<<; Saucedo and Edgar, 2007)." . . _:b419878219 . _:b419878147 . . _:b419878218 . . _:b6530312 . _:b6530305 "Based on this analysis and the nomenclature of Stavridi (Stavridi et al., >>2003<<), vertebrate Mob1's were given the assignations Mob1A\u2013E." . _:b419878134 . _:b419878228 . . . _:b6530303 . . _:b419878225 . . _:b419878224 . . _:b419878227 . . _:b6530280 "In animal cells, orthologues of the MEN/SIN seem to function in pathways associated with the negative regulation of cell proliferation and the promotion of apoptosis (Lai et al., >>2005<<). The Drosophila Mob1 orthologue Mats and the Sid2/Dbf2 orthologue Warts are essential in the Hippo/Salvador/Warts pathway, which regulates cell proliferation and organ development downstream of the proto-cadherin Fat (Hariharan, 2006;" . _:b6530332 . . _:b419878226 . _:b419878142 . . _:b6530308 . _:b419878209 . _:b419878186 . _:b419878167 . _:b6530309 . _:b419878221 . _:b419878183 . . _:b6530310 . . _:b419878133 . _:b6530311 . _:b419878202 . _:b6530289 _:b6530336 . _:b419878154 . _:b6530289 _:b6530337 . _:b6530308 . _:b6530304 . _:b6530289 _:b6530338 . _:b6530329 . _:b6530289 _:b6530339 . _:b6530275 "During mid-anaphase, Mob1 relocalizes from the spindle pole bodies to the bud-neck just before cytokinesis in a manner similar to that observed in fission yeast (Hou et al., 2000; Salimova et al., 2000; Luca et al., >>2001<<). And last, conditional alleles of mob1 demonstrated that the Mob1\u2013Dbf2 complex is required for dissociating Ipl1/Aurora B from the kinetochore and for maintaining chromosomal passenger proteins on the anaphase spindle (Stoepel et al.," . _:b6530289 _:b6530340 . _:b419878172 . _:b6530289 _:b6530341 . _:b6530305 . _:b6530289 _:b6530342 . _:b6530289 _:b6530343 . _:b6530289 _:b6530344 . _:b6530289 _:b6530345 . _:b6530306 . _:b6530289 _:b6530346 . "PMC0" . _:b6530357 "In all cases, Mob1 localization in animal cells seems highly reminiscent to that observed in yeast, where Mob1 binds with the spindle pole bodies in G2 (Hou et al., >>2000<<; Salimova et al., 2000; Luca et al., 2001), enters the nucleus and colocalizes with Cdc14 at the kinetochores (Stoepel et al., 2005)." . _:b6530289 _:b6530347 . _:b6530289 _:b6530348 . _:b6530289 _:b6530349 . _:b6530307 . _:b6530289 _:b6530350 . _:b6530289 _:b6530351 . _:b6530356 "Drosophila Mob4, which most resembles Mob3/phocein in humans, localizes to the spindle poles and weakly to kinetochores, and seems to play a role in spindle pole integrity (Trammell et al., >>2008<<)." . _:b419878175 . _:b6530316 . . _:b6530350 . _:b6530325 "The CPC localizes to the inner centromere early in mitosis and functions in organizing the spindle as well as monitoring tension at the kinetochore (May and Hardwick, >>2006<<; Ruchaud et al., 2007b). In addition, upon anaphase onset the CPC plays a critical role in organizing the spindle midzone and facilitating cytokinesis (Vader et al., 2008; Glotzer, 2009)." . _:b6530361 "anaphase onset, Mob1 and Dbf2/Sid2 relocalize to the forming actomyosin ring during cytokinesis, where in fission yeast the complex plays a role in initiating constriction of the actin ring and formation of the septum (Hou et al., >>2000<<; Salimova et al., 2000)." . _:b6530317 . _:b6530328 . _:b6530318 . . _:b6530319 . _:b6530289 _:b6530304 . . _:b6530289 _:b6530305 . _:b6530312 . _:b6530289 _:b6530306 . _:b6530289 _:b6530307 . _:b6530355 "And although localization of Mob1A to spindle poles and midbodies in mammalian cells has been reported previously (Bothos et al., >>2005<<), the kinetochore localization of Mob1 isoforms has not been reported to date, and represents a novel and exciting finding." . . _:b6530289 _:b6530308 . _:b6530289 _:b6530309 . _:b6530313 . _:b6530289 _:b6530310 . _:b6530289 _:b6530311 . _:b6530289 _:b6530312 . _:b6530289 _:b6530313 . _:b6530333 . _:b6530314 . _:b6530314 . _:b419878166 . _:b6530289 _:b6530314 . _:b6530289 _:b6530315 . _:b419878223 . _:b6530289 _:b6530316 . . _:b6530315 . _:b6530289 _:b6530317 . . . _:b6530289 _:b6530318 . _:b6530289 _:b6530319 . _:b6530289 _:b6530320 . _:b6530267 "regulates a phosphatase (Clp1), but in contrast to budding yeast, Clp1 is not required for mitotic exit but instead antagonizes mitotic cyclin-dependent kinase (Cdk) function to ensure the timely onset of cytokinesis (Guertin et al., >>2000<<; Chen et al., 2008)." . _:b6530289 _:b6530321 . _:b6530324 . _:b6530289 _:b6530322 . _:b6530331 "INCENP is required for Aurora B activation and function (Adams et al., 2000; Terada, 2001; Bishop and Schumacher, >>2002<<; Honda et al., 2003) and acts as a binding scaffold for the entire CPC complex (Sessa et al., 2005; Jeyaprakash et al., 2007)." . . _:b6530289 _:b6530323 . _:b6530289 _:b6530324 . _:b6530320 "with Mob1 in yeast (Luca and Winey, 1998; Lee et al., 2001; Tanaka et al., 2001) and in animal cells is recruited to the spindle poles, kinetochores and spindle midzone (Golsteyn et al., 1995; Glover et al., 1998; Barr et al., >>2004<<; van de Weerdt and Medema, 2006; Petronczki et al., 2008)." . _:b6530289 _:b6530325 . _:b6530325 . _:b6530289 _:b6530326 . _:b6530289 _:b6530327 . . _:b6530289 _:b6530328 . . _:b6530326 . _:b6530289 _:b6530329 . _:b6530289 _:b6530330 . _:b6530289 _:b6530331 . . _:b419878141 . _:b6530289 _:b6530332 . _:b6530289 _:b6530333 . _:b6530327 . _:b6530271 "In budding yeast, Mob1 is essential for mitotic exit, with mob1 mutants arresting in mitosis as large-budded cells with long, anaphase spindles (Luca and Winey, 1998; Luca et al., >>2001<<). Examination of Mob1 function in genetic backgrounds where the mitotic exit defect was overridden revealed that loss of Mob1 function results in cellular chains with segregated nuclei but no cytokinesis (Luca et al., 2001). During" . . _:b6530289 _:b6530334 . _:b6530289 _:b6530335 . _:b6530320 . _:b6530347 . _:b6530252 "introduction" . . _:b6530299 . _:b6530321 . _:b6530322 . _:b6530323 . _:b6530345 "which time Aurora B and the CPC localize to the spindle midzone during anaphase (Figure 8A, g\u2013h and m\u2013o), where the CPC influences the organization of the spindle midzone and factors required for the execution of cytokinesis (Glotzer, >>2009<<). However in Mob1A/B-depleted cells, we observed Aurora B and INCENP spread throughout the spindle midzone during early anaphase in 66.8% of cells scored (n = 482) with a fraction of the CPC remaining associated with the segregating" . _:b6530316 "Plk1 genetically interacts with Mob1 in yeast (Luca and Winey, 1998; Lee et al., >>2001<<; Tanaka et al., 2001) and in animal cells is recruited to the spindle poles, kinetochores and spindle midzone (Golsteyn et al., 1995; Glover et al., 1998; Barr et al., 2004; van de Weerdt and Medema, 2006; Petronczki et al., 2008)." . _:b6530332 . . _:b6530328 "In addition, upon anaphase onset the CPC plays a critical role in organizing the spindle midzone and facilitating cytokinesis (Vader et al., 2008; Glotzer, >>2009<<). Because Mob1 was also found at the kinetochores and spindle midzone (Figure 2 and Supplemental Figures 1 and 2), we wanted to determine whether Mob1 localization at the kinetochores was dependent on the CPC in mammalian cells. When" . . _:b419878165 . _:b6530333 . _:b6530321 . _:b6530295 "Mob1 and its effector kinase localize first to the spindle pole bodies until anaphase onset, at which time the complex relocalizes to the bud neck/actin ring (Frenz et al., 2000; Salimova et al., >>2000<<; Luca et al., 2001; Yoshida and Toh-e, 2001; Stoepel et al., 2005)." . _:b6530334 . . _:b6530335 . _:b419878178 . _:b6530328 . _:b419878191 . . _:b6530329 . _:b419878218 . _:b6530278 . _:b6530330 . _:b6530331 . _:b6530340 . _:b6530284 . _:b6530341 . . _:b6530342 . . _:b6530256 "cascades termed the septation initiation network (SIN) in Schizosaccharomyces pombe and the mitotic exit network (MEN) in Saccharomyces cerevisiae that regulate the temporal coordination of mitosis and cytokinesis (Jaspersen et al., >>1998<<; Bardin and Amon, 2001; McCollum and Gould, 2001; Krapp and Simanis, 2008)." . . _:b6530343 . . _:b6530336 . . _:b6530337 . _:b6530326 "The CPC localizes to the inner centromere early in mitosis and functions in organizing the spindle as well as monitoring tension at the kinetochore (May and Hardwick, 2006; Ruchaud et al., 2007b). In addition, upon anaphase onset the CPC plays a critical role in organizing the spindle midzone and facilitating cytokinesis (Vader et al., 2008; Glotzer, 2009)." . _:b6530338 . _:b6530339 . _:b6530348 . _:b6530322 . _:b419878199 . _:b6530349 . _:b6530286 "Moreover, there has been considerable expansion of MEN/SIN orthologues over the course of evolution with five isoforms of Mob1 and four Sid2/Dbf2 orthologues in the human genome (Hergovich et al., 2006b). In an effort to understand how MEN/SIN function is either conserved or has diverged in animal cells, we studied the localization dynamics of Mob1 and its function during mitosis in human cells. We report the different Mob1 isoforms" . _:b6530300 "Mob1A and B are 96% identical to each other at the amino acid level (Figure 1B) and are known to bind the NDR1/2- and Lats1/2 kinases (Bichsel et al., >>2004<<; Devroe et al., 2004; Bothos et al., 2005; Hergovich et al., 2005, 2006a; Chow et al., 2009)." . _:b6530350 . . _:b6530351 . . _:b6530348 "cells, Aurora B was spread out throughout the early anaphase spindle (Figure 8A, j\u2013l), but there were none of the dramatic phenotypes normally associated with compromised Aurora B function (Kallio et al., 2002; Hauf et al., >>2003<<). To determine whether there are any functional consequences to this altered localization we probed control- and Mob1A/Mob1B-depleted cells for histone H3 phosphorylation, a convenient marker for Aurora B activity." . _:b419878187 . . _:b6530344 . _:b6530367 . _:b419878152 . _:b6530345 . _:b419878130 . _:b419878131 . _:b6530309 . . _:b419878132 . . _:b419878133 . _:b6530346 . _:b6530342 "For these experiments, we used hTERT-immortalized retinal pigmented (RPE1) cells, which in comparison with HeLa cells display low rates of mitotic errors (Kigasawa et al., 1994; Jiang et al., >>1999<<; Thompson and Compton, 2008) and express only Mob1A\u2013D as detected by quantitative PCR (Figure 7A)." . _:b6530333 "INCENP is required for Aurora B activation and function (Adams et al., 2000; Terada, 2001; Bishop and Schumacher, 2002; Honda et al., 2003) and acts as a binding scaffold for the entire CPC complex (Sessa et al., >>2005<<; Jeyaprakash et al., 2007)." . _:b419878134 . _:b419878135 . _:b419878136 . _:b419878137 . _:b6530347 . _:b6530344 "In addition to its role in regulating mitotic exit, functional interactions between Mob1 and the CPC have been described in yeast (Stoepel et al., >>2005<<). Our own examination of Mob1 in human cells indicated that Mob1A localization to the kinetochore required INCENP and Aurora B (Figures 5 and 6 and Supplemental Figures 5 and 6) and to determine whether Mob1A was important for the CPC" . _:b6530297 . _:b419878138 . _:b419878139 . _:b419878140 . _:b419878141 . _:b6530356 . . _:b419878142 . _:b419878143 . . . _:b419878194 . . _:b6530357 . . _:b419878139 . _:b6530291 "In budding and fission yeast, Mob1 facilitates mitotic exit and cytokinesis by acting as a regulatory subunit for Dbf2/Sid2 kinase (Komarnitsky et al., 1998; Luca et al., >>2001<<; Devroe et al., 2004; Hou et al., 2004)." . _:b6530358 . _:b6530293 . _:b6530359 . _:b6530352 . _:b6530353 . _:b6530354 . _:b6530355 . _:b6530255 . _:b6530364 . . . . . _:b6530365 . _:b6530366 . _:b6530263 . _:b6530315 "Plk1 genetically interacts with Mob1 in yeast (Luca and Winey, >>1998<<; Lee et al., 2001; Tanaka et al., 2001) and in animal cells is recruited to the spindle poles, kinetochores and spindle midzone (Golsteyn et al., 1995; Glover et al., 1998; Barr et al., 2004; van de Weerdt and Medema, 2006; Petronczki et" . . _:b6530367 . _:b6530281 . _:b6530360 . _:b419878132 . _:b419878145 . _:b6530361 . _:b6530289 "results" . _:b419878220 . _:b6530362 . . _:b419878210 . . _:b6530363 . _:b6530316 . _:b6530366 "Work in budding yeast found that along with Cdc14, Mob1/Dbf2 partially localizes with kinetochores and is required for mobilization of the CPC from the centromere to the anaphase spindle (Stoepel et al., >>2005<<). We found that in Mob1A/Mob1B-depleted RPE1 cells, the CPC was spread throughout the spindle, with some residual localization on the chromosomes, suggesting that Mob1A was important for the correct redistribution of the CPC to the" . _:b419878185 . . _:b6530331 . . _:b419878179 . _:b6530290 "In budding and fission yeast, Mob1 facilitates mitotic exit and cytokinesis by acting as a regulatory subunit for Dbf2/Sid2 kinase (Komarnitsky et al., >>1998<<; Luca et al., 2001; Devroe et al., 2004; Hou et al., 2004)." . _:b6530252 _:b6530260 . . _:b6530368 . _:b6530252 _:b6530261 . _:b419878135 . _:b6530252 _:b6530262 . . _:b6530252 _:b6530263 . _:b6530359 "In all cases, Mob1 localization in animal cells seems highly reminiscent to that observed in yeast, where Mob1 binds with the spindle pole bodies in G2 (Hou et al., 2000; Salimova et al., 2000; Luca et al., >>2001<<), enters the nucleus and colocalizes with Cdc14 at the kinetochores (Stoepel et al., 2005)." . _:b6530252 _:b6530256 . _:b6530252 _:b6530257 . _:b6530369 . _:b6530252 _:b6530258 . _:b6530252 _:b6530259 . _:b6530252 _:b6530268 . _:b6530252 _:b6530269 . . _:b6530252 _:b6530270 . _:b6530252 _:b6530271 . _:b6530252 _:b6530264 . _:b6530315 . _:b6530290 . _:b6530252 _:b6530265 . _:b6530252 _:b6530266 . _:b6530252 _:b6530267 . _:b6530336 . . _:b6530252 _:b6530253 . . _:b6530252 _:b6530254 . _:b6530252 _:b6530255 . _:b6530270 . _:b6530330 . _:b6530306 . . _:b6530289 . . _:b419878144 . . _:b6530252 _:b6530276 . . _:b6530310 . _:b6530252 _:b6530277 . _:b6530252 _:b6530278 . _:b6530252 _:b6530279 . _:b419878208 . _:b6530252 _:b6530272 . _:b6530252 _:b6530273 . _:b419878209 . _:b6530252 _:b6530274 . _:b419878210 . _:b6530252 _:b6530275 . _:b419878211 . _:b6530252 _:b6530284 . _:b419878212 . _:b6530252 _:b6530285 . _:b419878213 . _:b6530252 _:b6530286 . _:b419878214 . _:b419878215 . _:b6530252 _:b6530280 . _:b419878216 . _:b6530252 _:b6530281 . . _:b419878217 . _:b6530252 _:b6530282 . _:b6530296 . _:b419878218 . _:b6530252 _:b6530283 . _:b419878219 . _:b419878220 . _:b6530287 . _:b419878221 . _:b419878222 . _:b419878223 . _:b419878224 . _:b6530259 . _:b419878159 . _:b419878225 . _:b419878226 . _:b419878227 . _:b419878228 . _:b419878189 . . . _:b6530274 "During mid-anaphase, Mob1 relocalizes from the spindle pole bodies to the bud-neck just before cytokinesis in a manner similar to that observed in fission yeast (Hou et al., 2000; Salimova et al., >>2000<<; Luca et al., 2001)." . . _:b419878160 . _:b419878176 . _:b419878177 . _:b419878178 . _:b419878179 . _:b419878180 . _:b419878181 . _:b419878182 . _:b419878183 . _:b419878184 . . . _:b419878185 . _:b6530252 . _:b419878186 . _:b419878187 . _:b419878188 . _:b419878133 "3"^^ . _:b419878189 . _:b419878190 . _:b6530291 . _:b419878191 . _:b419878192 . _:b419878132 "3"^^ . _:b419878193 . _:b419878194 . _:b419878195 . _:b419878196 . _:b419878135 "3"^^ . _:b6530265 . _:b419878197 . _:b419878176 . . _:b419878198 . _:b419878199 . _:b419878200 . _:b419878134 "3"^^ . _:b419878201 . _:b419878202 . _:b419878131 . _:b419878203 . _:b419878204 . _:b419878205 . . _:b419878206 . . _:b419878207 . _:b419878144 . . . _:b419878145 . _:b419878146 . _:b419878147 . _:b419878148 . _:b6530255 "Errors in either chromosome segregation or cytokinesis can be lethal during development and have a destabilizing effect on genomic stability (Kops et al., 2004, 2005; Weaver and Cleveland, >>2007<<). Much of our current understanding of how the cell cycle orchestrates the final stages of cell division in higher eukaryotes is based on genetic studies in unicellular fungi. And although nearly all cell cycle processes defined in yeast" . _:b419878149 . _:b419878131 "4"^^ . _:b6530318 . _:b419878150 . . _:b419878151 . _:b419878152 . _:b6530353 . _:b419878153 . _:b6530325 . _:b419878130 "4"^^ . _:b6530294 "Mob1 and its effector kinase localize first to the spindle pole bodies until anaphase onset, at which time the complex relocalizes to the bud neck/actin ring (Frenz et al., >>2000<<; Salimova et al., 2000; Luca et al., 2001; Yoshida and Toh-e, 2001; Stoepel et al., 2005)." . _:b419878154 . _:b419878155 . _:b419878156 . _:b419878141 "3"^^ . _:b419878157 . _:b419878158 . _:b419878159 . _:b419878160 . _:b419878140 "3"^^ . _:b419878161 . _:b419878162 . _:b6530307 . _:b419878163 . _:b419878164 . _:b419878143 "3"^^ . _:b419878165 . _:b419878166 . _:b6530253 "Errors in either chromosome segregation or cytokinesis can be lethal during development and have a destabilizing effect on genomic stability (Kops et al., >>2004<<, 2005; Weaver and Cleveland, 2007)." . . _:b419878167 . _:b419878168 . _:b419878142 "3"^^ . _:b419878169 . _:b419878170 . _:b419878171 . _:b419878172 . _:b6530347 "In Mob1A/Mob1B-depleted cells, Aurora B was spread out throughout the early anaphase spindle (Figure 8A, j\u2013l), but there were none of the dramatic phenotypes normally associated with compromised Aurora B function (Kallio et al., >>2002<<; Hauf et al., 2003). To determine whether there are any functional consequences to this altered localization we probed control- and Mob1A/Mob1B-depleted cells for histone H3 phosphorylation, a convenient marker for Aurora B activity." . _:b419878137 "3"^^ . _:b6530273 . _:b419878173 . _:b419878174 . _:b6530303 "Mob1A and B are 96% identical to each other at the amino acid level (Figure 1B) and are known to bind the NDR1/2- and Lats1/2 kinases (Bichsel et al., 2004; Devroe et al., 2004; Bothos et al., 2005; Hergovich et al., >>2005<<, 2006a; Chow et al., 2009)." . _:b6530262 "during anaphase and initiates a kinase cascade that terminates with the activation of a nuclear Dbf2-related (NDR) family kinase (Sid2/Dbf2) bound to its regulatory subunit Mps one binding (Mob) 1 (Schmidt et al., 1997; Bardin et al., >>2000<<). In fission yeast, the SIN pathway triggers the initiation of contraction of a centrally placed actomyosin ring and formation of the division septum (Krapp et al., 2004)." . _:b419878171 . _:b419878175 . _:b419878136 "3"^^ . . _:b6530304 "Mob1A and B are 96% identical to each other at the amino acid level (Figure 1B) and are known to bind the NDR1/2- and Lats1/2 kinases (Bichsel et al., 2004; Devroe et al., 2004; Bothos et al., 2005; Hergovich et al., 2005, 2006a; Chow et al., 2009). The other major cluster includes protozoan Mob1's, a single Drosophila Mob1 isoform and three vertebrate Mob1 isoforms arising from two gene duplication events (denoted by asterisks, Figure 1A)." . _:b419878139 "3"^^ . . . _:b419878138 "3"^^ . . _:b6530272 . . . _:b419878149 "2"^^ . . _:b419878162 . _:b6530275 . _:b419878148 "3"^^ . _:b6530268 . _:b6530317 "Plk1 genetically interacts with Mob1 in yeast (Luca and Winey, 1998; Lee et al., 2001; Tanaka et al., >>2001<<) and in animal cells is recruited to the spindle poles, kinetochores and spindle midzone (Golsteyn et al., 1995; Glover et al., 1998; Barr et al., 2004; van de Weerdt and Medema, 2006; Petronczki et al., 2008)." . _:b6530287 _:b6530288 . _:b419878151 "2"^^ . . _:b6530323 . _:b6530299 "Following the nomenclature used by Stavridi et al. (>>2003<<), we designated these proteins as Mob1A and Mob1B, respectively." . _:b6530369 "MKLP2 is antagonized by Cdk1 (Hummer and Mayer, >>2009<<), raising the possibility that MKLP2 is a principle target by which the mitotic exit network regulates the CPC." . _:b6530330 "INCENP is required for Aurora B activation and function (Adams et al., 2000; Terada, >>2001<<; Bishop and Schumacher, 2002; Honda et al., 2003) and acts as a binding scaffold for the entire CPC complex (Sessa et al., 2005; Jeyaprakash et al., 2007)." . _:b419878150 "2"^^ . _:b6530297 "and its effector kinase localize first to the spindle pole bodies until anaphase onset, at which time the complex relocalizes to the bud neck/actin ring (Frenz et al., 2000; Salimova et al., 2000; Luca et al., 2001; Yoshida and Toh-e, >>2001<<; Stoepel et al., 2005). As an initial effort toward understanding how the MEN might function in animal cells, we sought to follow Mob1 localization dynamics through mitosis in cultured human cells." . _:b419878145 "3"^^ . . _:b419878133 . _:b419878144 "3"^^ . _:b6530281 "The Drosophila Mob1 orthologue Mats and the Sid2/Dbf2 orthologue Warts are essential in the Hippo/Salvador/Warts pathway, which regulates cell proliferation and organ development downstream of the proto-cadherin Fat (Hariharan, >>2006<<; Harvey and Tapon, 2007; Matallanas et al., 2008)." . _:b419878147 "3"^^ . _:b419878132 . _:b419878146 "3"^^ . _:b419878135 . _:b6530351 "anaphase is the centralspindlin complex of MKLP1 and male germ cell Rac GTPase activating protein (MgcRacGap), which helps organize the spindle midzone and recruit the RhoGEF Ect2 to the cell equator (D'Avino et al., 2005; Glotzer, >>2005<<). Examination of both centralspindlin components in Mob1A/Mob1B-depleted cells revealed a similar phenotype in cells in early anaphase." . _:b6530276 "And last, conditional alleles of mob1 demonstrated that the Mob1\u2013Dbf2 complex is required for dissociating Ipl1/Aurora B from the kinetochore and for maintaining chromosomal passenger proteins on the anaphase spindle (Stoepel et al., >>2005<<), suggesting that in addition to its function in regulating Cdc14, the SIN/MEN pathway also may be involved in the regulation of the chromosomal passenger complex (CPC)." . _:b419878157 "2"^^ . _:b419878134 . _:b6530280 . _:b419878156 "2"^^ . . _:b419878159 "2"^^ . . _:b419878150 . _:b419878158 "2"^^ . _:b419878131 . . _:b6530355 . _:b6530323 "Consistent with previous reports, Plk1-depleted cells arrested in mitosis with a characteristic monopolar spindle with diffuse \u03B3-tubulin localization (Figure 4E; Lane and Nigg, >>1996<<; Donaldson et al., 2001)." . . . _:b419878153 "2"^^ . _:b419878130 . _:b6530265 "localization cell division cycle (Cdc) 14 phosphatase, preventing its sequestration in the nucleolus during late anaphase and allowing Cdc14 to antagonize CDK phosphorylation of key substrates (Jaspersen et al., 1998; Visintin et al., >>1998<<; Stegmeier and Amon, 2004)." . _:b6530289 _:b6530290 . _:b6530271 . _:b6530289 _:b6530291 . _:b6530362 "and Dbf2/Sid2 relocalize to the forming actomyosin ring during cytokinesis, where in fission yeast the complex plays a role in initiating constriction of the actin ring and formation of the septum (Hou et al., 2000; Salimova et al., >>2000<<). In plants, Mob1 localizes to microtubule-organizing centers in early prophase and in anaphase to the phragmoplast and forming cell plate (Citterio et al., 2006) suggesting that although there are fundamental differences in the manner by" . _:b6530289 _:b6530292 . _:b419878152 "2"^^ . _:b6530289 _:b6530293 . _:b419878141 . . . _:b6530289 _:b6530294 . . _:b6530289 _:b6530295 . _:b6530289 _:b6530296 . _:b419878155 "2"^^ . . _:b6530289 _:b6530297 . _:b419878140 . _:b6530289 _:b6530298 . _:b6530289 _:b6530299 . _:b6530354 . _:b6530258 "(SIN) in Schizosaccharomyces pombe and the mitotic exit network (MEN) in Saccharomyces cerevisiae that regulate the temporal coordination of mitosis and cytokinesis (Jaspersen et al., 1998; Bardin and Amon, 2001; McCollum and Gould, >>2001<<; Krapp and Simanis, 2008). Despite their similarities, some differences do exist in the mechanisms by which these pathways are activated as well their downstream targets (Bardin and Amon, 2001)." . _:b6530289 _:b6530300 . _:b419878154 "2"^^ . _:b6530289 _:b6530301 . _:b419878143 . _:b6530289 _:b6530302 . _:b6530258 . _:b6530289 _:b6530303 . _:b419878165 "2"^^ . _:b419878142 . _:b419878164 "2"^^ . _:b419878137 . . _:b419878167 "2"^^ . _:b419878136 . . _:b6530284 "And although mitotic exit defects have been reported in cells depleted of the Sid2/Dbf2 orthologues large tumor suppressor (Lats) 1 and Lats2 (McPherson et al., >>2004<<; Bothos et al., 2005), there have been relatively few studies examining the localization or functional roles of Mob1 in animal cell division." . _:b419878166 "2"^^ . . _:b6530363 "In plants, Mob1 localizes to microtubule-organizing centers in early prophase and in anaphase to the phragmoplast and forming cell plate (Citterio et al., >>2006<<) suggesting that although there are fundamental differences in the manner by which plants, fungi, and animal cells execute cytokinesis, Mob1 and its binding partners may be playing a conserved role in all of these organisms." . _:b6530319 "Plk1 genetically interacts with Mob1 in yeast (Luca and Winey, 1998; Lee et al., 2001; Tanaka et al., 2001) and in animal cells is recruited to the spindle poles, kinetochores and spindle midzone (Golsteyn et al., 1995; Glover et al., >>1998<<; Barr et al., 2004; van de Weerdt and Medema, 2006; Petronczki et al., 2008)." . _:b419878139 . _:b419878169 . _:b419878161 "2"^^ . _:b419878138 . _:b419878227 . _:b6530308 "The localization of Mob1 during mitosis was highly reminiscent of the key mitotic kinases Plk1 (Golsteyn et al., 1995; van de Weerdt and Medema, >>2006<<) and Aurora B kinase (Schumacher et al., 1998; Adams et al., 2001b; Giet and Glover, 2001; Murata-Hori et al., 2002), and we sought to determine whether Mob1's localization dynamics was dependent on these kinases." . _:b6530317 . _:b419878160 "2"^^ . . . _:b419878163 "2"^^ . _:b6530282 . _:b6530351 . _:b419878177 . _:b419878162 "2"^^ . _:b419878173 "2"^^ . _:b6530334 "is required for Aurora B activation and function (Adams et al., 2000; Terada, 2001; Bishop and Schumacher, 2002; Honda et al., 2003) and acts as a binding scaffold for the entire CPC complex (Sessa et al., 2005; Jeyaprakash et al., >>2007<<). To determine whether the catalytic activity of the CPC (Aurora B) is required for Mob1 recruitment to kinetochores, GFP-Mob1A\u2013, -C\u2013, and -D\u2013expressing HeLa cells were synchronized in prometaphase with nocodazole and then released into" . _:b419878172 "2"^^ . _:b419878175 "2"^^ . . _:b419878174 "2"^^ . _:b6530341 "For these experiments, we used hTERT-immortalized retinal pigmented (RPE1) cells, which in comparison with HeLa cells display low rates of mitotic errors (Kigasawa et al., >>1994<<; Jiang et al., 1999; Thompson and Compton, 2008) and express only Mob1A\u2013D as detected by quantitative PCR (Figure 7A)." . _:b6530273 "During mid-anaphase, Mob1 relocalizes from the spindle pole bodies to the bud-neck just before cytokinesis in a manner similar to that observed in fission yeast (Hou et al., >>2000<<; Salimova et al., 2000; Luca et al., 2001)." . . _:b419878169 "2"^^ . _:b419878168 "2"^^ . . _:b419878171 "2"^^ . _:b419878138 . _:b419878184 . _:b6530309 "The localization of Mob1 during mitosis was highly reminiscent of the key mitotic kinases Plk1 (Golsteyn et al., 1995; van de Weerdt and Medema, 2006) and Aurora B kinase (Schumacher et al., >>1998<<; Adams et al., 2001b; Giet and Glover, 2001; Murata-Hori et al., 2002), and we sought to determine whether Mob1's localization dynamics was dependent on these kinases." . _:b419878170 "2"^^ . _:b6530365 "The CPC functions in chromosomal organization and alignment, kinetochore assembly, microtubule attachment, spindle midzone assembly, and cytokinesis (Ruchaud et al., 2007a; Vader et al., >>2007<<). Work in budding yeast found that along with Cdc14, Mob1/Dbf2 partially localizes with kinetochores and is required for mobilization of the CPC from the centromere to the anaphase spindle (Stoepel et al., 2005)." . _:b419878181 "2"^^ . . _:b419878136 . _:b419878207 . _:b6530261 . _:b419878180 "2"^^ . _:b419878204 . _:b419878183 "2"^^ . _:b419878156 . _:b6530298 "localize first to the spindle pole bodies until anaphase onset, at which time the complex relocalizes to the bud neck/actin ring (Frenz et al., 2000; Salimova et al., 2000; Luca et al., 2001; Yoshida and Toh-e, 2001; Stoepel et al., >>2005<<). As an initial effort toward understanding how the MEN might function in animal cells, we sought to follow Mob1 localization dynamics through mitosis in cultured human cells." . _:b419878206 . _:b6530352 "discussion" . . _:b419878182 "2"^^ . . _:b419878177 "2"^^ . _:b419878180 . _:b6530363 . _:b6530361 . _:b419878176 "2"^^ . _:b6530283 "Sid2/Dbf2 orthologue Warts are essential in the Hippo/Salvador/Warts pathway, which regulates cell proliferation and organ development downstream of the proto-cadherin Fat (Hariharan, 2006; Harvey and Tapon, 2007; Matallanas et al., >>2008<<). And although mitotic exit defects have been reported in cells depleted of the Sid2/Dbf2 orthologues large tumor suppressor (Lats) 1 and Lats2 (McPherson et al., 2004; Bothos et al., 2005), there have been relatively few studies" . _:b6530348 . _:b419878225 . _:b6530362 . _:b6530344 . _:b419878179 "2"^^ . . _:b419878178 "2"^^ . . _:b419878189 "2"^^ . _:b6530357 . . _:b419878188 "2"^^ . _:b6530302 . _:b6530358 . _:b419878191 "2"^^ . _:b419878182 . _:b6530266 . _:b419878190 "2"^^ . _:b419878185 "2"^^ . _:b419878170 . _:b419878216 . _:b419878184 "2"^^ . _:b419878158 . _:b419878212 . _:b419878187 "2"^^ . . _:b419878186 "2"^^ . _:b419878197 "2"^^ . _:b6530352 . . _:b6530296 "Mob1 and its effector kinase localize first to the spindle pole bodies until anaphase onset, at which time the complex relocalizes to the bud neck/actin ring (Frenz et al., 2000; Salimova et al., 2000; Luca et al., >>2001<<; Yoshida and Toh-e, 2001; Stoepel et al., 2005)." . . _:b419878196 "2"^^ . . _:b6530340 . _:b419878199 "2"^^ . . _:b419878198 "2"^^ . _:b419878193 "2"^^ . _:b419878205 . . _:b419878192 "2"^^ . _:b6530252 . _:b6530343 "For these experiments, we used hTERT-immortalized retinal pigmented (RPE1) cells, which in comparison with HeLa cells display low rates of mitotic errors (Kigasawa et al., 1994; Jiang et al., 1999; Thompson and Compton, >>2008<<) and express only Mob1A\u2013D as detected by quantitative PCR (Figure 7A)." . _:b6530360 "to that observed in yeast, where Mob1 binds with the spindle pole bodies in G2 (Hou et al., 2000; Salimova et al., 2000; Luca et al., 2001), enters the nucleus and colocalizes with Cdc14 at the kinetochores (Stoepel et al., >>2005<<). After anaphase onset, Mob1 and Dbf2/Sid2 relocalize to the forming actomyosin ring during cytokinesis, where in fission yeast the complex plays a role in initiating constriction of the actin ring and formation of the septum (Hou et al.," . _:b6530360 . _:b419878195 "2"^^ . _:b6530253 . _:b6530285 . _:b419878194 "2"^^ . _:b6530339 . _:b6530254 . _:b6530311 . _:b419878174 . _:b6530366 . . _:b6530255 . _:b419878205 "2"^^ . _:b419878161 . _:b419878204 "2"^^ . . _:b419878207 "2"^^ . . _:b419878206 "2"^^ . _:b6530327 "In addition, upon anaphase onset the CPC plays a critical role in organizing the spindle midzone and facilitating cytokinesis (Vader et al., >>2008<<; Glotzer, 2009)." . _:b6530266 "cycle (Cdc) 14 phosphatase, preventing its sequestration in the nucleolus during late anaphase and allowing Cdc14 to antagonize CDK phosphorylation of key substrates (Jaspersen et al., 1998; Visintin et al., 1998; Stegmeier and Amon, >>2004<<). In fission yeast, the SIN also regulates a phosphatase (Clp1), but in contrast to budding yeast, Clp1 is not required for mitotic exit but instead antagonizes mitotic cyclin-dependent kinase (Cdk) function to ensure the timely onset of" . _:b6530314 "Plk1 is a major regulator throughout mitosis, playing roles in the transition G2/M, centrosomal maturation, spindle bipolarity and cytokinesis (Glover et al., 1998; van de Weerdt and Medema, >>2006<<). Plk1 genetically interacts with Mob1 in yeast (Luca and Winey, 1998; Lee et al., 2001; Tanaka et al., 2001) and in animal cells is recruited to the spindle poles, kinetochores and spindle midzone (Golsteyn et al., 1995; Glover et al.," . . _:b419878201 "2"^^ . _:b6530270 "In budding yeast, Mob1 is essential for mitotic exit, with mob1 mutants arresting in mitosis as large-budded cells with long, anaphase spindles (Luca and Winey, >>1998<<; Luca et al., 2001)." . _:b6530288 "The 2\u2212\u0394\u0394Ct (Livak and Schmittgen, >>2001<<) method was used for calculating -fold change in transcript levels in controls and Mob1-depleted cells." . _:b419878149 . _:b6530260 . _:b419878200 "2"^^ . . _:b419878151 . _:b419878203 "2"^^ . _:b6530261 . _:b419878219 . _:b419878214 . _:b419878202 "2"^^ . _:b6530262 . _:b6530346 . _:b419878213 "2"^^ . _:b6530321 "and Winey, 1998; Lee et al., 2001; Tanaka et al., 2001) and in animal cells is recruited to the spindle poles, kinetochores and spindle midzone (Golsteyn et al., 1995; Glover et al., 1998; Barr et al., 2004; van de Weerdt and Medema, >>2006<<; Petronczki et al., 2008)." . _:b6530263 . . _:b419878168 . _:b419878226 . _:b419878212 "2"^^ . _:b6530256 . _:b419878215 "2"^^ . _:b6530257 . . _:b419878214 "2"^^ . _:b6530337 "6E and Supplemental Figure 6, E and M) as was Ser10 phosphorylation of histone H3 (Figure 6F and Supplemental Figure 6, F and N), an established marker for Aurora B activity (Hsu et al., 2000; Adams et al., 2001a; Giet and Glover, >>2001<<; George et al., 2006). Thus, either siRNA depletion or pharmacologic inhibition of the CPC blocked Mob1 recruitment to the kinetochores." . _:b6530258 . _:b6530324 . _:b6530327 . _:b419878209 "2"^^ . _:b6530259 . _:b419878208 "2"^^ . _:b6530268 . . _:b419878211 "2"^^ . _:b6530269 . _:b419878210 "2"^^ . _:b6530270 . _:b419878221 "2"^^ . _:b6530305 . _:b6530271 . . _:b419878220 "2"^^ . _:b6530264 . . . _:b419878223 "2"^^ . _:b6530265 . . _:b419878222 "2"^^ . _:b6530266 . _:b419878211 . _:b6530334 . _:b419878217 "2"^^ . _:b6530267 . _:b6530346 "Because all four components of the CPC function as a single functional unit (Jeyaprakash et al., >>2007<<), the fact that both Aurora B and INCENP displayed this phenotype suggested that the mobilization of the entire CPC was being affected." . _:b419878216 "2"^^ . _:b6530288 . _:b6530276 . _:b419878219 "2"^^ . _:b6530277 . _:b419878146 . _:b419878218 "2"^^ . _:b6530278 . _:b6530277 . _:b6530335 "in the absence of Aurora B activity (Figure 6E and Supplemental Figure 6, E and M) as was Ser10 phosphorylation of histone H3 (Figure 6F and Supplemental Figure 6, F and N), an established marker for Aurora B activity (Hsu et al., >>2000<<; Adams et al., 2001a; Giet and Glover, 2001; George et al., 2006). Thus, either siRNA depletion or pharmacologic inhibition of the CPC blocked Mob1 recruitment to the kinetochores." . _:b6530279 . _:b6530365 . _:b419878163 . _:b419878228 "2"^^ . _:b6530272 . _:b419878196 . _:b419878195 . _:b419878215 . _:b6530273 . . _:b419878224 . _:b6530274 . . _:b6530335 . _:b419878225 "2"^^ . _:b6530275 . _:b6530301 . _:b419878224 "2"^^ . _:b6530284 . . _:b419878227 "2"^^ . _:b6530285 . . . . _:b419878226 "2"^^ . _:b6530286 . . _:b6530287 . . _:b6530310 "The localization of Mob1 during mitosis was highly reminiscent of the key mitotic kinases Plk1 (Golsteyn et al., 1995; van de Weerdt and Medema, 2006) and Aurora B kinase (Schumacher et al., 1998; Adams et al., 2001b; Giet and Glover, 2001; Murata-Hori et al., 2002), and we sought to determine whether Mob1's localization dynamics was dependent on these kinases." . . _:b6530280 . _:b6530281 . . _:b6530282 . _:b419878157 . _:b6530277 "In plants, Mob1 is localized to the forming division site (phragmoplast) in a manner analogous to that seen in yeast (Van Damme et al., >>2004<<; Citterio et al., 2006)." . . . _:b6530283 . _:b419878148 . _:b6530318 "Plk1 genetically interacts with Mob1 in yeast (Luca and Winey, 1998; Lee et al., 2001; Tanaka et al., 2001) and in animal cells is recruited to the spindle poles, kinetochores and spindle midzone (Golsteyn et al., >>1995<<; Glover et al., 1998; Barr et al., 2004; van de Weerdt and Medema, 2006; Petronczki et al., 2008)." . _:b6530292 . _:b6530292 . _:b6530337 . _:b6530293 . . _:b6530342 . _:b6530294 . _:b6530264 "the cytoplasmic localization cell division cycle (Cdc) 14 phosphatase, preventing its sequestration in the nucleolus during late anaphase and allowing Cdc14 to antagonize CDK phosphorylation of key substrates (Jaspersen et al., >>1998<<; Visintin et al., 1998; Stegmeier and Amon, 2004)." . . _:b6530268 "Cytokinetic failure, multinucleation, and failure to septate have been reported in temperature sensitive mob1 alleles in S. pombe (Hou et al., >>2000<<; Salimova et al., 2000)." . _:b6530295 . _:b419878153 . _:b419878137 . "10.1091%2Fmbc.E09-06-0471" . _:b6530288 . _:b6530279 . _:b6530329 "INCENP is required for Aurora B activation and function (Adams et al., >>2000<<; Terada, 2001; Bishop and Schumacher, 2002; Honda et al., 2003) and acts as a binding scaffold for the entire CPC complex (Sessa et al., 2005; Jeyaprakash et al., 2007)." . _:b6530289 . _:b6530326 . _:b419878217 . _:b6530261 "on the spindle poles during anaphase and initiates a kinase cascade that terminates with the activation of a nuclear Dbf2-related (NDR) family kinase (Sid2/Dbf2) bound to its regulatory subunit Mps one binding (Mob) 1 (Schmidt et al., >>1997<<; Bardin et al., 2000). In fission yeast, the SIN pathway triggers the initiation of contraction of a centrally placed actomyosin ring and formation of the division septum (Krapp et al., 2004)." . _:b419878173 . _:b6530290 . . _:b419878149 . _:b6530291 . . _:b6530269 "Cytokinetic failure, multinucleation, and failure to septate have been reported in temperature sensitive mob1 alleles in S. pombe (Hou et al., 2000; Salimova et al., >>2000<<). In budding yeast, Mob1 is essential for mitotic exit, with mob1 mutants arresting in mitosis as large-budded cells with long, anaphase spindles (Luca and Winey, 1998; Luca et al., 2001). Examination of Mob1 function in genetic" . _:b419878203 . . _:b419878148 . _:b6530300 . _:b419878151 . _:b6530259 "pombe and the mitotic exit network (MEN) in Saccharomyces cerevisiae that regulate the temporal coordination of mitosis and cytokinesis (Jaspersen et al., 1998; Bardin and Amon, 2001; McCollum and Gould, 2001; Krapp and Simanis, >>2008<<). Despite their similarities, some differences do exist in the mechanisms by which these pathways are activated as well their downstream targets (Bardin and Amon, 2001)." . _:b6530301 . _:b6530307 "The localization of Mob1 during mitosis was highly reminiscent of the key mitotic kinases Plk1 (Golsteyn et al., >>1995<<; van de Weerdt and Medema, 2006) and Aurora B kinase (Schumacher et al., 1998; Adams et al., 2001b; Giet and Glover, 2001; Murata-Hori et al., 2002), and we sought to determine whether Mob1's localization dynamics was dependent on these" . _:b6530283 . _:b6530294 . _:b419878150 . _:b6530302 . . _:b6530340 "Alteration of Mob1 activity in yeast compromises Dbf2/Sid2- as well as Cdc14/Clp1 function (Mah et al., 2001) and alters CPC relocation to the spindle midzone (Stoepel et al., >>2005<<). To identify the possible functions of Mob1 at the kinetochore or spindle midzone, we depleted Mob1 isoforms in cultured human cells." . _:b419878145 . _:b419878200 . _:b6530269 . _:b6530303 . _:b419878144 . . _:b6530296 . . _:b419878147 . _:b6530297 . _:b6530350 "of the CPC during anaphase is the centralspindlin complex of MKLP1 and male germ cell Rac GTPase activating protein (MgcRacGap), which helps organize the spindle midzone and recruit the RhoGEF Ect2 to the cell equator (D'Avino et al., >>2005<<; Glotzer, 2005). Examination of both centralspindlin components in Mob1A/Mob1B-depleted cells revealed a similar phenotype in cells in early anaphase." . . _:b419878146 . _:b6530298 . . . _:b419878157 . _:b6530267 . _:b6530299 . _:b419878143 . _:b419878156 . . _:b6530324 "Consistent with previous reports, Plk1-depleted cells arrested in mitosis with a characteristic monopolar spindle with diffuse \u03B3-tubulin localization (Figure 4E; Lane and Nigg, 1996; Donaldson et al., >>2001<<). In Plk1-depeleted cells, Mob1A was lost from the spindle poles (66%; n = 372 cells) but kinetochore localization was unaffected (Figure 4D, J and M). Identical results were obtained when GFP-Mob1C and Mob1D were expressed in" . _:b419878159 . _:b419878158 . _:b6530320 . _:b419878153 . _:b6530254 . _:b419878152 . . _:b6530369 . _:b419878155 . _:b6530276 . . _:b6530341 . _:b419878154 . _:b419878130 . _:b6530298 . _:b6530257 "initiation network (SIN) in Schizosaccharomyces pombe and the mitotic exit network (MEN) in Saccharomyces cerevisiae that regulate the temporal coordination of mitosis and cytokinesis (Jaspersen et al., 1998; Bardin and Amon, >>2001<<; McCollum and Gould, 2001; Krapp and Simanis, 2008). Despite their similarities, some differences do exist in the mechanisms by which these pathways are activated as well their downstream targets (Bardin and Amon, 2001)." . _:b419878165 . _:b419878164 . . _:b419878167 . . _:b6530260 "Despite their similarities, some differences do exist in the mechanisms by which these pathways are activated as well their downstream targets (Bardin and Amon, >>2001<<). In both organisms, a monomeric GTPase localizes on the spindle poles during anaphase and initiates a kinase cascade that terminates with the activation of a nuclear Dbf2-related (NDR) family kinase (Sid2/Dbf2) bound to its regulatory" . _:b419878166 . . . _:b419878161 . _:b6530322 "al., 2001; Tanaka et al., 2001) and in animal cells is recruited to the spindle poles, kinetochores and spindle midzone (Golsteyn et al., 1995; Glover et al., 1998; Barr et al., 2004; van de Weerdt and Medema, 2006; Petronczki et al., >>2008<<). Mob1 and Plk1 colocalized in mitotic cells (Figure 3, D\u2013F), and to determine whether Plk1 influenced Mob1 localization in dividing cells, HeLa cells transiently expressing GFP-Mob1A, -C, and -D were depleted of Plk1 by RNA interference." . . . _:b419878160 . _:b6530306 "Aurora B has a broad signal, spanning the inner centromere (Carmena and Earnshaw, >>2003<<) and when colocalized with Mob1A, Mob1A could be detected at both ends of the Aurora B signal (Figure 3, A\u2013C)." . _:b419878163 . _:b419878164 . _:b6530364 . _:b6530332 "INCENP is required for Aurora B activation and function (Adams et al., 2000; Terada, 2001; Bishop and Schumacher, 2002; Honda et al., >>2003<<) and acts as a binding scaffold for the entire CPC complex (Sessa et al., 2005; Jeyaprakash et al., 2007)." . _:b419878162 . _:b6530279 "Similarly, Mob1 down-regulation in Trypanosoma alters the timing of cytokinesis and placement of the cleavage furrow (Hammarton et al., >>2005<<). In animal cells, orthologues of the MEN/SIN seem to function in pathways associated with the negative regulation of cell proliferation and the promotion of apoptosis (Lai et al., 2005). The Drosophila Mob1 orthologue Mats and the" . _:b6530272 "Examination of Mob1 function in genetic backgrounds where the mitotic exit defect was overridden revealed that loss of Mob1 function results in cellular chains with segregated nuclei but no cytokinesis (Luca et al., >>2001<<). During mid-anaphase, Mob1 relocalizes from the spindle pole bodies to the bud-neck just before cytokinesis in a manner similar to that observed in fission yeast (Hou et al., 2000; Salimova et al., 2000; Luca et al., 2001). And last," . _:b419878173 . . _:b419878172 . _:b419878198 . _:b419878175 . _:b6530364 "The CPC functions in chromosomal organization and alignment, kinetochore assembly, microtubule attachment, spindle midzone assembly, and cytokinesis (Ruchaud et al., 2007a; Vader et al., 2007). Work in budding yeast found that along with Cdc14, Mob1/Dbf2 partially localizes with kinetochores and is required for mobilization of the CPC from the centromere to the anaphase spindle (Stoepel et al., 2005)." . _:b6530300 . _:b419878174 . _:b6530311 "The localization of Mob1 during mitosis was highly reminiscent of the key mitotic kinases Plk1 (Golsteyn et al., 1995; van de Weerdt and Medema, 2006) and Aurora B kinase (Schumacher et al., 1998; Adams et al., 2001b; Giet and Glover, >>2001<<; Murata-Hori et al., 2002), and we sought to determine whether Mob1's localization dynamics was dependent on these kinases." . _:b419878192 . _:b419878169 . . _:b419878168 . _:b6530287 "materials and methods" . _:b419878188 . _:b419878171 . _:b6530312 "mitosis was highly reminiscent of the key mitotic kinases Plk1 (Golsteyn et al., 1995; van de Weerdt and Medema, 2006) and Aurora B kinase (Schumacher et al., 1998; Adams et al., 2001b; Giet and Glover, 2001; Murata-Hori et al., >>2002<<), and we sought to determine whether Mob1's localization dynamics was dependent on these kinases." . _:b6530264 . _:b419878170 . _:b6530368 . _:b6530352 _:b6530356 . _:b6530304 . _:b6530352 _:b6530357 . _:b6530352 _:b6530358 . _:b419878181 . _:b6530352 _:b6530359 . _:b6530367 "It has been proposed that during anaphase there is a gradient of Aurora B activity at the spindle midzone that acts to influence the late events of mitosis (Fuller et al., >>2008<<). It is possible then that in the Mob1-depleted cells, the diffuse distribution of Aurora B along the entire spindle effectively broadens the activity gradient and thus maintains phosphohistone reactivity and the widened distribution of" . _:b6530352 _:b6530353 . _:b6530352 _:b6530354 . _:b419878180 . _:b6530352 _:b6530355 . _:b6530274 . _:b6530352 _:b6530364 . _:b6530352 _:b6530365 . _:b6530352 _:b6530366 . _:b419878183 . . _:b6530352 _:b6530367 . . _:b6530352 _:b6530360 . _:b6530352 _:b6530361 . _:b6530352 _:b6530362 . _:b419878182 . . _:b6530352 _:b6530363 . _:b6530358 "In all cases, Mob1 localization in animal cells seems highly reminiscent to that observed in yeast, where Mob1 binds with the spindle pole bodies in G2 (Hou et al., 2000; Salimova et al., >>2000<<; Luca et al., 2001), enters the nucleus and colocalizes with Cdc14 at the kinetochores (Stoepel et al., 2005)." . . _:b419878197 . _:b419878177 . _:b6530302 "Mob1A and B are 96% identical to each other at the amino acid level (Figure 1B) and are known to bind the NDR1/2- and Lats1/2 kinases (Bichsel et al., 2004; Devroe et al., 2004; Bothos et al., >>2005<<; Hergovich et al., 2005, 2006a; Chow et al., 2009)." . _:b419878176 . . . _:b419878179 . _:b6530292 "In budding and fission yeast, Mob1 facilitates mitotic exit and cytokinesis by acting as a regulatory subunit for Dbf2/Sid2 kinase (Komarnitsky et al., 1998; Luca et al., 2001; Devroe et al., >>2004<<; Hou et al., 2004)." . _:b6530256 . _:b419878178 . . _:b419878201 . _:b6530285 "And although mitotic exit defects have been reported in cells depleted of the Sid2/Dbf2 orthologues large tumor suppressor (Lats) 1 and Lats2 (McPherson et al., 2004; Bothos et al., >>2005<<), there have been relatively few studies examining the localization or functional roles of Mob1 in animal cell division." . . _:b419878189 . _:b6530257 . _:b419878188 . _:b6530359 . _:b419878191 . _:b6530336 "Aurora B activity (Figure 6E and Supplemental Figure 6, E and M) as was Ser10 phosphorylation of histone H3 (Figure 6F and Supplemental Figure 6, F and N), an established marker for Aurora B activity (Hsu et al., 2000; Adams et al., 2001a; Giet and Glover, 2001; George et al., 2006). Thus, either siRNA depletion or pharmacologic inhibition of the CPC blocked Mob1 recruitment to the kinetochores." . _:b419878190 . _:b6530260 . . _:b419878185 . _:b419878184 . _:b419878187 . _:b6530254 "Errors in either chromosome segregation or cytokinesis can be lethal during development and have a destabilizing effect on genomic stability (Kops et al., 2004, >>2005<<; Weaver and Cleveland, 2007)." . _:b419878140 . _:b6530295 . . _:b419878186 . . _:b419878197 . _:b419878196 . _:b6530349 "The relocalization of the CPC from the centromeres to the spindle midzone requires the action of the kinesin-like motor MKLP2 (Gruneberg et al., >>2004<<), and to determine whether the effect of Mob1A/Mob1B on CPC localization involved this motor, cells were depleted of Mob1A/Mob1B and probed for MKLP2." . _:b419878199 . _:b6530345 . _:b6530301 "Mob1A and B are 96% identical to each other at the amino acid level (Figure 1B) and are known to bind the NDR1/2- and Lats1/2 kinases (Bichsel et al., 2004; Devroe et al., >>2004<<; Bothos et al., 2005; Hergovich et al., 2005, 2006a; Chow et al., 2009)." . _:b6530339 "Alteration of Mob1 activity in yeast compromises Dbf2/Sid2- as well as Cdc14/Clp1 function (Mah et al., >>2001<<) and alters CPC relocation to the spindle midzone (Stoepel et al., 2005). To identify the possible functions of Mob1 at the kinetochore or spindle midzone, we depleted Mob1 isoforms in cultured human cells." . . _:b419878198 . _:b419878193 . _:b6530349 . _:b419878222 . _:b6530352 _:b6530368 . _:b6530286 . _:b6530352 _:b6530369 . _:b6530368 "MKLP2 is required for the CPC to correctly load onto the spindle midzone during anaphase, as well as for the midzone targeting of the MEN effector Cdc14A (Gruneberg et al., >>2004<<). For both the CPC and MKLP2, the absence of Mob1A/B only affected midzone localization early in anaphase (Figures 8 and 10), and that as anaphase and mitotic exit progressed MKLP2/CPC recruitment to the midzone recovered. MKLP2 is" . _:b419878208 . _:b419878192 . . _:b419878195 . _:b6530262 . _:b419878194 . _:b419878205 . _:b6530253 . _:b419878204 . . _:b419878207 . . _:b419878206 . . _:b6530278 "In plants, Mob1 is localized to the forming division site (phragmoplast) in a manner analogous to that seen in yeast (Van Damme et al., 2004; Citterio et al., >>2006<<). Similarly, Mob1 down-regulation in Trypanosoma alters the timing of cytokinesis and placement of the cleavage furrow (Hammarton et al., 2005). In animal cells, orthologues of the MEN/SIN seem to function in pathways associated with the" . _:b6530354 "However, most reports in the literature ascribe roles for MEN/SIN orthologues in tumor suppressor pathways regulating organ size and cell proliferation (Pan, 2007; Saucedo and Edgar, >>2007<<). Here, we demonstrate that in human cells, Mob1 associates with mitotic structures in a manner highly reminiscent of the localization dynamics observed for Mob1 in yeast and higher plants, and functions during anaphase to regulate the" . . _:b419878201 . _:b6530282 "orthologue Mats and the Sid2/Dbf2 orthologue Warts are essential in the Hippo/Salvador/Warts pathway, which regulates cell proliferation and organ development downstream of the proto-cadherin Fat (Hariharan, 2006; Harvey and Tapon, >>2007<<; Matallanas et al., 2008)." . _:b6530313 "Plk1 is a major regulator throughout mitosis, playing roles in the transition G2/M, centrosomal maturation, spindle bipolarity and cytokinesis (Glover et al., >>1998<<; van de Weerdt and Medema, 2006)." . _:b419878190 . _:b419878213 . _:b419878200 . _:b419878203 . _:b419878202 . _:b6530313 . . _:b419878213 . _:b6530356 . _:b419878212 . _:b419878215 . _:b6530343 . . _:b419878214 . _:b6530338 "Figure 6, E and M) as was Ser10 phosphorylation of histone H3 (Figure 6F and Supplemental Figure 6, F and N), an established marker for Aurora B activity (Hsu et al., 2000; Adams et al., 2001a; Giet and Glover, 2001; George et al., >>2006<<). Thus, either siRNA depletion or pharmacologic inhibition of the CPC blocked Mob1 recruitment to the kinetochores." . . _:b419878228 . _:b419878155 . _:b419878209 . _:b419878208 . _:b6530319 .