The Replication Protein Cdc6 Suppresses Centrosome Over-Duplication in a Manner Independent of Its ATPase Activity

Mol Cells. 2017 Dec 31;40(12):925-934. doi: 10.14348/molcells.2017.0191. Epub 2017 Dec 12.

Abstract

The Cdc6 protein is essential for the initiation of chromosomal replication and functions as a licensing factor to maintain chromosome integrity. During the S and G2 phases of the cell cycle, Cdc6 has been found to inhibit the recruitment of pericentriolar material (PCM) proteins to the centrosome and to suppress centrosome over-duplication. In this report, we analyzed the correlation between these two functions of Cdc6 at the centrosome. Cdc6 depletion increased the population of cells showing centrosome over-duplication and premature centrosome separation; Cdc6 expression reversed these changes. Deletion and fusion experiments revealed that the 18 amino acid residues (197-214) of Cdc6, which were fused to the Cdc6-centrosomal localization signal, suppressed centrosome over-duplication and premature centrosome separation. Cdc6 mutant proteins that showed defective ATP binding or hydrolysis did not exhibit a significant difference in suppressing centrosome over-duplication, compared to the wild type protein. In contrast to the Cdc6-mediated inhibition of PCM protein recruitment to the centrosome, the independence of Cdc6 on its ATPase activity for suppressing centrosome over-duplication, along with the difference between the Cdc6 protein regions participating in the two functions, suggested that Cdc6 controls centrosome duplication in a manner independent of its recruitment of PCM proteins to the centrosome.

Keywords: ATPase; Cdc6; DNA replication; cell cycle; centrosome.

MeSH terms

  • Adenosine Triphosphatases / metabolism*
  • Cell Cycle Checkpoints
  • Cell Cycle Proteins / deficiency
  • Cell Cycle Proteins / metabolism*
  • Cell Line, Tumor
  • Centrioles / metabolism
  • Centrosome / enzymology
  • Centrosome / metabolism
  • Centrosome / physiology*
  • DNA Replication / physiology*
  • Humans
  • Nuclear Proteins / deficiency
  • Nuclear Proteins / metabolism*
  • Transfection

Substances

  • CDC6 protein, human
  • Cell Cycle Proteins
  • Nuclear Proteins
  • Adenosine Triphosphatases