title: Nek2 targets the mitotic checkpoint proteins Mad2 and Cdc20: a mechanism for aneuploidy in cancer.
abstract: In mitosis, the duplicated chromosomes are separated and equally distributed to progeny cells under the guidance of the spindle, a dynamic microtubule network. Previous studies revealed a mitotic checkpoint that prevents segregation of the chromosomes until all of the chromosomes are properly attached to microtubules through the kinetochores. A variety of kinetochore-localized proteins, including Mad2 and Cdc20, have been implicated in controlling the mitotic checkpoint. Here we report that both Mad2 and Cdc20 can physically associate with Nek2, a serine/threonine kinase implicated in centrosome functions. We show that, similar to Nek2, the endogenous Cdc20 protein can be detected in the centrosome and the spindle poles. Both Cdc20 and Mad2 can be phosphorylated by Nek2. Moreover, our studies demonstrate that overexpression of Nek2 enhances the ability of Mad2 to induce a delay in mitosis. These observations indicate that Nek2 may act upon the Mad2-Cdc20 protein complex and play a critical role in regulating the mitotic checkpoint protein complex. We propose that overexpression of Nek2 may promote aneuploidy by disrupting the control of the mitotic checkpoint.
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Abramson Family Cancer Research Institute, 252 John Morgan Building, 3600 Hamilton Walk, Philadelphia, PA 19104, USA.
authors.forename: Qingdu
authors.initials: Q
authors.lastname: Liu
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Hirohashi
authors.forename: Xiulian
authors.initials: X
authors.lastname: Du
authors.forename: Mark I
authors.initials: MI
authors.lastname: Greene
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wang
mesh_terms: D000782:Aneuploidy; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D064199:Cdc20 Proteins; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002455:Cell Division; D002460:Cell Line; D020440:Gene Duplication; D006801:Humans; D064246:Mad2 Proteins; D008938:Mitosis / Q000502:physiology; D000072379:NIMA-Related Kinases; D009369:Neoplasms / Q000235:genetics* / Q000473:pathology; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D017384:Sequence Deletion; D008941:Spindle Apparatus / Q000235:genetics
chemical_list: D002135:Calcium-Binding Proteins; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins; C577697:MAD2L1 protein, human; D064246:Mad2 Proteins; D012097:Repressor Proteins; C577488:CDC20 protein, human; C089441:NEK2 protein, human; D000072379:NIMA-Related Kinases; D017346:Protein Serine-Threonine Kinases