The centrosome-specific phosphorylation of Cnn by Polo/Plk1 drives Cnn scaffold assembly and centrosome maturation

Dev Cell. 2014 Mar 31;28(6):659-69. doi: 10.1016/j.devcel.2014.02.013. Epub 2014 Mar 20.

Abstract

Centrosomes are important cell organizers. They consist of a pair of centrioles surrounded by pericentriolar material (PCM) that expands dramatically during mitosis-a process termed centrosome maturation. How centrosomes mature remains mysterious. Here, we identify a domain in Drosophila Cnn that appears to be phosphorylated by Polo/Plk1 specifically at centrosomes during mitosis. The phosphorylation promotes the assembly of a Cnn scaffold around the centrioles that is in constant flux, with Cnn molecules recruited continuously around the centrioles as the scaffold spreads slowly outward. Mutations that block Cnn phosphorylation strongly inhibit scaffold assembly and centrosome maturation, whereas phosphomimicking mutations allow Cnn to multimerize in vitro and to spontaneously form cytoplasmic scaffolds in vivo that organize microtubules independently of centrosomes. We conclude that Polo/Plk1 initiates the phosphorylation-dependent assembly of a Cnn scaffold around centrioles that is essential for efficient centrosome maturation in flies.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Animals, Genetically Modified
  • Brain / cytology
  • Brain / metabolism
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Cells, Cultured
  • Centrosome / metabolism*
  • Cytoplasm / metabolism
  • Drosophila Proteins / chemistry
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism*
  • Drosophila melanogaster / genetics
  • Drosophila melanogaster / growth & development
  • Drosophila melanogaster / metabolism*
  • Homeodomain Proteins / chemistry
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / metabolism*
  • Image Processing, Computer-Assisted
  • Immunoprecipitation
  • Microtubules / metabolism
  • Mitosis / physiology*
  • Molecular Sequence Data
  • Phosphorylation
  • Protein Multimerization
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism*
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism*
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Sequence Homology, Amino Acid
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
  • Two-Hybrid System Techniques

Substances

  • Cell Cycle Proteins
  • Drosophila Proteins
  • Homeodomain Proteins
  • Proto-Oncogene Proteins
  • Recombinant Fusion Proteins
  • cnn protein, Drosophila
  • polo protein, Drosophila
  • Protein-Serine-Threonine Kinases
  • polo-like kinase 1