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pubmed:abstractText |
Accurate chromosome alignment at metaphase and subsequent segregation of condensed chromosomes is a complex process involving elaborate and only partially characterized molecular machinery. Although several spindle associated molecular motors have been shown to be essential for mitotic function, only a few chromosome arm--associated motors have been described. Here, we show that human chromokinesin human HKIF4A (HKIF4A) is an essential chromosome-associated molecular motor involved in faithful chromosome segregation. HKIF4A localizes in the nucleoplasm during interphase and on condensed chromosome arms during mitosis. It accumulates in the mid-zone from late anaphase and localizes to the cytokinetic ring during cytokinesis. RNA interference--mediated depletion of HKIF4A in human cells results in defective prometaphase organization, chromosome mis-alignment at metaphase, spindle defects, and chromosome mis-segregation. HKIF4A interacts with the condensin I and II complexes and HKIF4A depletion results in chromosome hypercondensation, suggesting that HKIF4A is required for maintaining normal chromosome architecture. Our results provide functional evidence that human KIF4A is a novel component of the chromosome condensation and segregation machinery functioning in multiple steps of mitotic division.
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pubmed:affiliation |
National Cancer Institute, National Institutes of Health, Bldg. 41, Rm. B 507, 41 Library Dr., Bethesda, MD 20892, USA. mazumdam@mail.nih.gov
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