title: Phosphorylation-dependent binding of 14-3-3 to Par3beta, a human Par3-related cell polarity protein.
abstract: Mammalian Par3alpha and Par3beta/Par3L participate in cell polarity establishment and localize to tight junctions of epithelial cells; Par3alpha acts via binding to atypical PKC (aPKC). Here we show that Par3beta as well as Par3alpha interacts with 14-3-3 proteins in a phosphorylation-dependent manner. In the interaction, Ser-746 of Par3beta and the corresponding residue of Par3alpha (Ser-814) likely play a crucial role, since replacement of these residues by unphosphorylatable alanine results in a loss of interacting activity. The mutant Par3 proteins with the replacement are correctly recruited to tight junctions of MDCK cells and to membrane ruffles induced by an active form of the small GTPase Rac in HeLa cells. Thus, the interaction with 14-3-3 appears to be dispensable to Par3 localization. Consistent with this, the Par3alpha-14-3-3 interaction does not inhibit the Par3alpha-aPKC association required for the Par3alpha localization, although the aPKC-binding site lies close to the Ser-814-containing, 14-3-3-interacting region.
authors.affiliation: Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Izaki
authors.forename: Sachiko
authors.initials: S
authors.lastname: Kamakura
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Kohjima
authors.forename: Hideki
authors.initials: H
authors.lastname: Sumimoto
mesh_terms: D048948:14-3-3 Proteins / Q000378:metabolism*; D000409:Alanine / Q000737:chemistry; D000469:Alkaline Phosphatase / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D019521:Body Patterning; D019556:COS Cells; D002352:Carrier Proteins; D002417:Cattle; D002460:Cell Line; D019070:Cell Lineage; D018076:DNA, Complementary / Q000378:metabolism; D004285:Dogs; D004847:Epithelial Cells / Q000166:cytology; D015723:Gene Library; D006367:HeLa Cells; D006801:Humans; D047468:Immunoprecipitation; D007422:Intestines / Q000201:enzymology; D008565:Membrane Proteins / Q000737:chemistry*; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D018179:Receptors, Thrombin / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D012694:Serine / Q000737:chemistry; D020798:Two-Hybrid System Techniques
chemical_list: D048948:14-3-3 Proteins; D002352:Carrier Proteins; D018076:DNA, Complementary; D008565:Membrane Proteins; C471157:PARD3B protein, human; D018179:Receptors, Thrombin; C105295:protease-activated receptor 3; D012694:Serine; D000469:Alkaline Phosphatase; D000409:Alanine