title: Two Polo-like kinase 4 binding domains in Asterless perform distinct roles in regulating kinase stability.
abstract: Plk4 (Polo-like kinase 4) and its binding partner Asterless (Asl) are essential, conserved centriole assembly factors that induce centriole amplification when overexpressed. Previous studies found that Asl acts as a scaffolding protein; its N terminus binds Plk4's tandem Polo box cassette (PB1-PB2) and targets Plk4 to centrioles to initiate centriole duplication. However, how Asl overexpression drives centriole amplification is unknown. In this paper, we investigated the Asl-Plk4 interaction in Drosophila melanogaster cells. Surprisingly, the N-terminal region of Asl is not required for centriole duplication, but a previously unidentified Plk4-binding domain in the C terminus is required. Mechanistic analyses of the different Asl regions revealed that they act uniquely during the cell cycle: the Asl N terminus promotes Plk4 homodimerization and autophosphorylation during interphase, whereas the Asl C terminus stabilizes Plk4 during mitosis. Therefore, Asl affects Plk4 in multiple ways to regulate centriole duplication. Asl not only targets Plk4 to centrioles but also modulates Plk4 stability and activity, explaining the ability of overexpressed Asl to drive centriole amplification.
authors: Department of Cellular and Molecular Medicine and University of Arizona Cancer Center, University of Arizona, Tucson, AZ 85724 Department of Cellular and Molecular Medicine and University of Arizona Cancer Center, University of Arizona, Tucson, AZ 85724.
authors: Joseph E
authors: JE
authors: Klebba
authors: National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892.
authors: Brian J
authors: BJ
authors: Galletta
authors: Department of Cellular and Molecular Medicine and University of Arizona Cancer Center, University of Arizona, Tucson, AZ 85724 Department of Cellular and Molecular Medicine and University of Arizona Cancer Center, University of Arizona, Tucson, AZ 85724.
authors: Jonathan
authors: J
authors: Nye
authors: National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892 Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599.
authors: Karen M
authors: KM
authors: Plevock
authors: Department of Cellular and Molecular Medicine and University of Arizona Cancer Center, University of Arizona, Tucson, AZ 85724 Department of Cellular and Molecular Medicine and University of Arizona Cancer Center, University of Arizona, Tucson, AZ 85724.
authors: Daniel W
authors: DW
authors: Buster
authors: Department of Cellular and Molecular Medicine and University of Arizona Cancer Center, University of Arizona, Tucson, AZ 85724 Department of Cellular and Molecular Medicine and University of Arizona Cancer Center, University of Arizona, Tucson, AZ 85724.
authors: Natalie A
authors: NA
authors: Hollingsworth
authors: Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599.
authors: Kevin C
authors: KC
authors: Slep
authors: National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892 nasser.rusan@nih.gov gcrogers@email.arizona.edu.
authors: Nasser M
authors: NM
authors: Rusan
authors: Department of Cellular and Molecular Medicine and University of Arizona Cancer Center, University of Arizona, Tucson, AZ 85724 Department of Cellular and Molecular Medicine and University of Arizona Cancer Center, University of Arizona, Tucson, AZ 85724 nasser.rusan@nih.gov gcrogers@email.arizona.edu.
authors: Gregory C
authors: GC
authors: Rogers
mesh_terms: D000818:Animals; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000378:metabolism; D002460:Cell Line; D002502:Centrioles / Q000378:metabolism*; D029721:Drosophila Proteins / Q000737:chemistry* / Q000235:genetics; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism*; D004795:Enzyme Stability; D008938:Mitosis / Q000235:genetics; D010766:Phosphorylation; D011485:Protein Binding; D055503:Protein Multimerization; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry*; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D034741:RNA, Small Interfering
chemical_list: C539309:Asl protein, Drosophila; D018797:Cell Cycle Proteins; D029721:Drosophila Proteins; D034741:RNA, Small Interfering; D017346:Protein Serine-Threonine Kinases; C522064:Sak protein, Drosophila