hPOC5 is a centrin-binding protein required for assembly of full-length centrioles.
Centrin has been shown to be involved in centrosome biogenesis in a variety of eukaryotes. In this study, we characterize hPOC5, a conserved centrin-binding protein that contains Sfi1p-like repeats. hPOC5 is localized, like centrin, in the distal portion of human centrioles. hPOC5 recruitment to procentrioles occurs during G2/M, a process that continues up to the full maturation of the centriole during the next cell cycle and is correlated with hyperphosphorylation of the protein. In the absence of hPOC5, RPE1 cells arrest in G1 phase, whereas HeLa cells show an extended S phase followed by cell death. We show that hPOC5 is not required for the initiation of procentriole assembly but is essential for building the distal half of centrioles. Interestingly, the hPOC5 family reveals an evolutionary divergence between vertebrates and organisms like Drosophila melanogaster or Caenorhabditis elegans, in which the loss of hPOC5 may correlate with the conspicuous differences in centriolar structure.
Institut Curie, Centre National de la Recherche Scientifique Unité Mixte de Recherche 144, Paris, France.
Juliette
J
Azimzadeh
Polla
P
Hergert
Annie
A
Delouvée
Ursula
U
Euteneuer
Etienne
E
Formstecher
Alexey
A
Khodjakov
Michel
M
Bornens
D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002502:Centrioles / Q000378:metabolism* / Q000648:ultrastructure; D017124:Conserved Sequence; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D005434:Flow Cytometry; D006367:HeLa Cells; D006801:Humans; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D016196:S Phase; D016415:Sequence Alignment; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
C493956:CDKN1A protein, human; D002352:Carrier Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; C540807:POC5 protein, human; D010750:Phosphoproteins; D016159:Tumor Suppressor Protein p53; D015662:Trimethoprim, Sulfamethoxazole Drug Combination