title: CPAP is a cell-cycle regulated protein that controls centriole length.
abstract: Centriole duplication involves the growing of a procentriole (progeny centriole) next to the proximal end of each pre-existing centriole (parental centriole). The molecular mechanisms that regulate procentriole elongation remain obscure. We show here that expression of the centriolar protein CPAP (centrosomal P4.1-associated protein) is carefully regulated during the cell cycle, with the protein being degraded in late mitosis. Depletion of CPAP inhibited centrosome duplication, whereas excess CPAP induced the formation of elongated procentriole-like structures (PLSs), which contain stable microtubules and several centriolar proteins. Ultrastructural analysis revealed that these structures are similar to procentrioles with elongated microtubules. Overexpression of a CPAP mutant (CPAP-377EE) that does not bind to tubulin dimers significantly inhibited the formation of CPAP-induced PLSs. Together, these results suggest that CPAP is a new regulator of centriole length and its intrinsic tubulin-dimer binding activity is required for procentriole elongation.
authors.affiliation: Institute of Biomedical Sciences, Taipei, Taiwan.
authors.forename: Chieh-Ju C
authors.initials: CJ
authors.lastname: Tang
authors.forename: Ru-Huei
authors.initials: RH
authors.lastname: Fu
authors.forename: Kuo-Sheng
authors.initials: KS
authors.lastname: Wu
authors.forename: Wen-Bin
authors.initials: WB
authors.lastname: Hsu
authors.forename: Tang K
authors.initials: TK
authors.lastname: Tang
mesh_terms: D002453:Cell Cycle / Q000235:genetics / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000502:physiology; D002460:Cell Line; D045744:Cell Line, Tumor; D002502:Centrioles / Q000378:metabolism*; D005434:Flow Cytometry; D006367:HeLa Cells; D006801:Humans; D015151:Immunoblotting; D047468:Immunoprecipitation; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008938:Mitosis / Q000235:genetics / Q000502:physiology; D008954:Models, Biological; D034741:RNA, Small Interfering; D014404:Tubulin / Q000378:metabolism; D054875:Ubiquitination
chemical_list: C414735:CENPJ protein, human; D018797:Cell Cycle Proteins; D008869:Microtubule-Associated Proteins; D034741:RNA, Small Interfering; C497202:SASS6 protein, human; D014404:Tubulin