title: CPAP interacts with 14-3-3 in a cell cycle-dependent manner.
abstract: We have previously reported that CPAP (Centrosomal Protein 4.1-Associated Protein) carries a novel microtubule-destabilizing motif that may regulate microtubule dynamics at the centrosome. In this study, we searched for conserved sequence motifs in CPAP and identified two classical 14-3-3 binding sites. The interaction between CPAP and 14-3-3 was demonstrated by both yeast two-hybrid and co-immunoprecipitation experiments. Further analyses revealed that the 14-3-3 binding motif is located within the C-terminal domain of CPAP. Alkaline phosphatase treatment disrupted CPAP binding to 14-3-3, suggesting that phosphorylation is required for the interaction. Mutation of serine 1109 to alanine (S1109A) in the 14-3-3 binding motif completely abolished the association of CPAP with 14-3-3. Taking together, these results imply that phosphorylation of CPAP on serine 1109 is required for 14-3-3 binding. Furthermore, we observed that the interaction between CPAP and 14-3-3 was significantly reduced in mitotic cells, suggesting that 14-3-3 binding to CPAP is regulated during cell cycle progression. In summary, our results show a direct interaction between CPAP and 14-3-3, and this interaction appears to be phosphorylation and cell cycle dependent.
authors.affiliation: Graduate Institute of Life Sciences, National Defense Medical Center, Taipei 114, Taiwan, ROC.
authors.forename: Chiung-Ya
authors.initials: CY
authors.lastname: Chen
authors.forename: Monilola A
authors.initials: MA
authors.lastname: Olayioye
authors.forename: Geoffrey J
authors.initials: GJ
authors.lastname: Lindeman
authors.forename: Tang K
authors.initials: TK
authors.lastname: Tang
mesh_terms: D048948:14-3-3 Proteins / Q000378:metabolism*; D002453:Cell Cycle / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D011485:Protein Binding; D025941:Protein Interaction Mapping
chemical_list: D048948:14-3-3 Proteins; C414735:CENPJ protein, human; D008869:Microtubule-Associated Proteins