title: Characterization of the mechanisms controlling Greatwall activity.
abstract: Here we investigate the mechanisms regulating Greatwall (Gwl), a serine/threonine kinase essential for promoting the correct timing of mitosis. We identify Gwl as a unique AGC kinase that, unlike most AGC members, appears to be devoid of a hydrophobic motif despite the presence of a functional hydrophobic pocket. Our results suggest that Gwl activation could be mediated by the binding of its hydrophobic pocket to the hydrophobic motif of another AGC kinase. Our molecular modeling and mutagenic analysis also indicate that Gwl displays a conserved tail/linker site whose phosphorylation mediates kinase activation by promoting the interaction of this phosphorylated residue with two lysines at the N terminus. This interaction could stabilize the αC-helix and maintain kinase activity. Finally, the different phosphorylation sites on Gwl are identified, and the role of each one in the regulation of Gwl kinase activity is determined. Our data suggest that only the phosphorylation of the tail/linker site, located outside the putative T loop, appears to be essential for Gwl activation. In summary, our results identify Gwl as a member of the AGC family of kinases that appears to be regulated by unique mechanisms and that differs from the other members of this family.
authors: Universités Montpellier 2 et 1, Centre de Recherche de Biochimie Macromoléculaire, CNRS UMR 5237, IFR 122, 1919 Route de Mende, 34293 Montpellier cedex 5, France.
authors: Suzanne
authors: S
authors: Vigneron
authors: Aicha
authors: A
authors: Gharbi-Ayachi
authors: Anne-Aurélie
authors: AA
authors: Raymond
authors: Andrew
authors: A
authors: Burgess
authors: Jean-Claude
authors: JC
authors: Labbé
authors: Gilles
authors: G
authors: Labesse
authors: Bernard
authors: B
authors: Monsarrat
authors: Thierry
authors: T
authors: Lorca
authors: Anna
authors: A
authors: Castro
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D018797:Cell Cycle Proteins; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D013058:Mass Spectrometry; D008869:Microtubule-Associated Proteins / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D008938:Mitosis; D008969:Molecular Sequence Data; D009154:Mutation; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D014981:Xenopus; D029867:Xenopus Proteins / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism*
chemical_list: D018797:Cell Cycle Proteins; D008869:Microtubule-Associated Proteins; D029867:Xenopus Proteins; C544010:MASTL protein, Xenopus; C555237:MASTL protein, human; D017346:Protein Serine-Threonine Kinases