Regulation of centromeric cohesion by sororin independently of the APC/C.
Regulated separation of sister chromatids is the key event of mitosis. Sister chromatids remain cohered from the moment of DNA duplication until anaphase. Two known factors account for cohesion: DNA catenations and cohesin complexes. Premature loss of centromeric cohesion is prevented by the spindle checkpoint. Here we show that sororin, a protein implicated in promoting cohesion through effects on cohesin complexes, is involved in maintenance of cohesion in response to the spindle checkpoint. Sororin-depleted cells reach prometaphase with cohered sister chromatids and are able to form metaphase plates. However, loss of cohesion in anaphase is asynchronous and cells are unresponsive to the spindle checkpoint, accumulating with separated sisters scattered throughout the cytoplasm. These phenotypes are similar to those seen after Shugoshin depletion, suggesting that sororin and Shugoshin might act in concert. Furthermore, sororin-depleted and Shugoshin-depleted cells lose cohesion independently of the APC/C. Therefore, sororin and Shugoshin protect centromeric cohesion in response to the spindle checkpoint, but prevent the removal of cohesion by a mechanism independent of the APC/C.
Díaz-Martínez
Laura A
LA
Department of Genetics, Cell Biology and Development, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA.
Giménez-Abián
Juan F
JF
Clarke
Duncan J
DJ
D048868:Adaptor Proteins, Signal Transducing; D064173:Anaphase-Promoting Complex-Cyclosome; D018797:Cell Cycle Proteins / Q000502:physiology*; D002503:Centromere / Q000378:metabolism* / Q000502:physiology; D002842:Chromatids / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008941:Spindle Apparatus / Q000502:physiology; D043743:Ubiquitin-Protein Ligase Complexes / Q000502:physiology*
D048868:Adaptor Proteins, Signal Transducing; C500695:CDCA5 protein, human; D018797:Cell Cycle Proteins; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome