title: Polo-like kinase 4 autodestructs by generating its Slimb-binding phosphodegron.
abstract: Polo-like kinase 4 (Plk4) is a conserved master regulator of centriole assembly. Previously, we found that Drosophila Plk4 protein levels are actively suppressed during interphase. Degradation of interphase Plk4 prevents centriole overduplication and is mediated by the ubiquitin-ligase complex SCF(Slimb/βTrCP). Since Plk4 stability depends on its activity, we studied the consequences of inactivating Plk4 or perturbing its phosphorylation state within its Slimb-recognition motif (SRM). Mass spectrometry of in-vitro-phosphorylated Plk4 and Plk4 purified from cells reveals that it is directly responsible for extensively autophosphorylating and generating its Slimb-binding phosphodegron. Phosphorylatable residues within this regulatory region were systematically mutated to determine their impact on Plk4 protein levels and centriole duplication when expressed in S2 cells. Notably, autophosphorylation of a single residue (Ser293) within the SRM is critical for Slimb binding and ubiquitination. Our data also demonstrate that autophosphorylation of numerous residues flanking S293 collectively contribute to establishing a high-affinity binding site for SCF(Slimb). Taken together, our findings suggest that Plk4 directly generates its own phosphodegron and can do so without the assistance of an additional kinase(s).
authors.affiliation: Department of Cellular and Molecular Medicine, University of Arizona Cancer Center, University of Arizona, Tucson, AZ 85724, USA.
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Klebba
authors.affiliation: Department of Cellular and Molecular Medicine, University of Arizona Cancer Center, University of Arizona, Tucson, AZ 85724, USA.
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Buster
authors.affiliation: Department of Cellular and Molecular Medicine, University of Arizona Cancer Center, University of Arizona, Tucson, AZ 85724, USA.
authors.forename: Annie L
authors.initials: AL
authors.lastname: Nguyen
authors.affiliation: Proteomics Core, National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Stephen
authors.initials: S
authors.lastname: Swatkoski
authors.affiliation: Proteomics Core, National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Marjan
authors.initials: M
authors.lastname: Gucek
authors.affiliation: National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Nasser M
authors.initials: NM
authors.lastname: Rusan
authors.affiliation: Department of Cellular and Molecular Medicine, University of Arizona Cancer Center, University of Arizona, Tucson, AZ 85724, USA. Electronic address: gcrogers@email.arizona.edu.
authors.forename: Gregory C
authors.initials: GC
authors.lastname: Rogers
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D002502:Centrioles / Q000378:metabolism; D004330:Drosophila / Q000166:cytology / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D012694:Serine / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*
chemical_list: D018797:Cell Cycle Proteins; D029721:Drosophila Proteins; C110233:slmb protein, Drosophila; D012694:Serine; D044767:Ubiquitin-Protein Ligases; D017346:Protein Serine-Threonine Kinases; C522064:Sak protein, Drosophila