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pubmed:abstractText |
Despite the fact that the chromosomal passenger complex is well known to regulate kinetochore behavior in mitosis, no functional link has yet been established between the complex and kinetochore structure. In addition, remarkably little is known about how the complex targets to centromeres. Here, in a study of caspase-8 activation during death receptor-induced apoptosis in MCF-7 cells, we have found that cleaved caspase-8 rapidly translocates to the nucleus and that this translocation is correlated with loss of the centromere protein (CENP)-C, resulting in extensive disruption of centromeres. Caspase-8 activates cytoplasmic caspase-7, which is likely to be the primary caspase responsible for cleavage of CENP-C and INCENP, a key chromosomal passenger protein. Caspase-mediated cleavage of CENP-C and INCENP results in their mislocalization and the subsequent mislocalization of Aurora B kinase. Our results demonstrate that the chromosomal passenger complex is displaced from centromeres as a result of caspase activation. Furthermore, mutation of the primary caspase cleavage sites of INCENP and CENP-C and expression of noncleavable CENP-C or INCENP prevent the mislocalization of the passenger complex after caspase activation. Our studies provide the first evidence for a functional interplay between the passenger complex and CENP-C.
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