title: Hec1 sequentially recruits Zwint-1 and ZW10 to kinetochores for faithful chromosome segregation and spindle checkpoint control.
abstract: Faithful chromosome segregation is essential for maintaining the genomic integrity, which requires coordination among chromosomes, kinetochores, centrosomes and spindles during mitosis. Previously, we discovered a novel coiled-coil protein, highly expressed in cancer 1 (Hec1), which is indispensable for this process. However, the precise underlying mechanism remains unclear. Here, we show that Hec1 directly interacts with human ZW10 interacting protein (Zwint-1), a binding partner of Zeste White 10 (ZW10) that is required for chromosome motility and spindle checkpoint control. In mitotic cells, Hec1 transiently forms complexes with Zwint-1 and ZW10 in a temporal and spatial manner. Although the three proteins have variable cell cycle-dependent expression profiles, they can only be co-immunoprecipitated during M phase. Immunofluorescent study showed that Hec1 and Zwint-1 co-localize at kinetochores beginning at prophase and that ZW10 joins them later at prometaphase. Depletion of Hec1 impairs the recruitment of both Zwint-1 and ZW10 to kinetochores, while depletion of Zwint-1 abrogates the kinetochore localization of ZW10 but not Hec1. The results suggest that the localization of Hec1 at kinetochores is required for the sequential recruitment of Zwint-1 and ZW10. Disrupting this recruitment by inhibiting the expression of Hec1 or Zwint-1 causes chromosome missegregation, spindle checkpoint failure, and eventually cell death upon cytokinesis. Taken together, these results, at least in part, provide a molecular basis to explain how Hec1 plays a crucial role for spindle checkpoint control and faithful chromosome segregation.
authors.affiliation: Department of Biological Chemistry, University of California, Irvine, CA 92697-4037, USA.
authors.forename: Y-T
authors.initials: YT
authors.lastname: Lin
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
authors.forename: G
authors.initials: G
authors.lastname: Wu
authors.forename: W-H
authors.initials: WH
authors.lastname: Lee
mesh_terms: D018797:Cell Cycle Proteins / Q000502:physiology; D045744:Cell Line, Tumor; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D020090:Chromosome Segregation / Q000502:physiology*; D003598:Cytoskeletal Proteins; D004591:Electrophoresis, Polyacrylamide Gel; D005455:Fluorescent Antibody Technique; D015870:Gene Expression; D006367:HeLa Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D018386:Kinetochores / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008938:Mitosis / Q000502:physiology; D009687:Nuclear Proteins / Q000378:metabolism*; D034741:RNA, Small Interfering; D008941:Spindle Apparatus / Q000378:metabolism*; D014162:Transfection
chemical_list: D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D003598:Cytoskeletal Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008869:Microtubule-Associated Proteins; C120529:NDC80 protein, human; D009687:Nuclear Proteins; D034741:RNA, Small Interfering; C488261:ZW10 protein, human; C413695:ZWINT protein, human