Cdk1/Erk2- and Plk1-dependent phosphorylation of a centrosome protein, Cep55, is required for its recruitment to midbody and cytokinesis.

Centrosomes in mammalian cells have recently been implicated in cytokinesis; however, their role in this process is poorly defined. Here, we describe a human coiled-coil protein, Cep55 (centrosome protein 55 kDa), that localizes to the mother centriole during interphase. Despite its association with gamma-TuRC anchoring proteins CG-NAP and Kendrin, Cep55 ...
is not required for microtubule nucleation. Upon mitotic entry, centrosome dissociation of Cep55 is triggered by Erk2/Cdk1-dependent phosphorylation at S425 and S428. Furthermore, Cep55 locates to the midbody and plays a role in cytokinesis, as its depletion by siRNA results in failure of this process. S425/428 phosphorylation is required for interaction with Plk1, enabling phosphorylation of Cep55 at S436. Cells expressing phosphorylation-deficient mutant forms of Cep55 undergo cytokinesis failure. These results highlight the centrosome as a site to organize phosphorylation of Cep55, enabling it to relocate to the midbody to function in mitotic exit and cytokinesis.
Mesh Terms:
A Kinase Anchor Proteins, Adaptor Proteins, Signal Transducing, Amino Acid Sequence, Animals, CDC2 Protein Kinase, Calmodulin-Binding Proteins, Cell Cycle Proteins, Cell Division, Cell Line, Centrosome, Computational Biology, Cytoskeletal Proteins, Humans, Mitogen-Activated Protein Kinase 1, Molecular Sequence Data, Nuclear Proteins, Phosphorylation, Protein Kinases, Protein Serine-Threonine Kinases, Proto-Oncogene Proteins, RNA, Small Interfering, Sequence Alignment, Tissue Distribution
Dev Cell
Date: Oct. 01, 2005
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