Abstract
Centrosome cohesion and segregation are accurately regulated to prevent an aberrant separation of duplicated centrosomes and to ensure the correct formation of bipolar spindles by a tight coupling with cell cycle machinery. CPAP is a centrosome protein with five coiled-coil domains and plays an important role in the control of brain size in autosomal recessive primary microcephaly. Previous studies showed that CPAP interacts with tubulin and controls centriole length. Here, we reported that CPAP forms a homodimer during interphase, and the fifth coiled-coil domain of CPAP is required for its dimerization. Moreover, this self-interaction is required for maintaining centrosome cohesion and preventing the centrosome from splitting before the G(2)/M phase. Our biochemical studies show that CPAP forms homodimers in vivo. In addition, both monomeric and dimeric CPAP are required for accurate cell division, suggesting that the temporal dynamics of CPAP homodimerization is tightly regulated during the cell cycle. Significantly, our results provide evidence that CPAP is phosphorylated during mitosis, and this phosphorylation releases its intermolecular interaction. Taken together, these results suggest that cell cycle-regulated phosphorylation orchestrates the dynamics of CPAP molecular interaction and centrosome splitting to ensure genomic stability in cell division.
Highlights
Mammalian centrosomes, the major microtubule-organizing centers, consist of a pair of centrioles normally localized at the periphery of the nucleus and surrounded by a number of proteins collectively referred to as pericentriolar material [1,2,3]
We demonwas detected as a doublet in asynchronized cells and prome- strated that CPAP plays a role in centrosome cohesion
Our experimental results show that CPAP molecules exist as dimers, and this dimerization is mainly mediated by the fifth coiled-coil domain
Summary
The major microtubule-organizing centers, consist of a pair of centrioles normally localized at the periphery of the nucleus and surrounded by a number of proteins collectively referred to as pericentriolar material [1,2,3]. Depletion of CPAP can block the overduplication of centrioles induced by overexpression of PLK4 [18]. Previous studies have illustrated that CPAP in like fashion to SAS4 plays a critical role in centriole biogenesis and centrosome size (19 –21). We found that both partial depletion of CPAP by CPAP siRNA and overexpression of the C terminus of CPAP induced an increase in centrosome splitting, indicating that CPAP functions on centrosome cohesion. CPAP is a mitotic phosphorylation protein, and phosphorylation blocks the self-interaction of CPAP These results demonstrate that negative regulation of CPAP self-interaction by mitotic phosphorylation is required for accurate centrosome cohesion and splitting during the cell cycle
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
