Ribosomal protein S3 is phosphorylated by Cdk1/cdc2 during G2/M phase

BMB Rep. 2011 Aug;44(8):529-34. doi: 10.5483/bmbrep.2011.44.8.529.

Abstract

Ribosomal protein S3 (rpS3) is a multifunctional protein involved in translation, DNA repair, and apoptosis. The relationship between rpS3 and cyclin-dependent kinases (Cdks) involved in cell cycle regulation is not yet known. Here, we show that rpS3 is phosphorylated by Cdk1 in G2/M phase. Co-immunoprecipitation and GST pull-down assays revealed that Cdk1 interacted with rpS3. An in vitro kinase assay showed that Cdk1 phosphorylated rpS3 protein. Phosphorylation of rpS3 increased in nocodazole-arrested mitotic cells; however, treatment with Cdk1 inhibitor or Cdk1 siRNA significantly attenuated this phosphorylation event. The phosphorylation of a mutant form of rpS3, T221A, was significantly reduced compared with wild-type rpS3. Decreased phosphorylation and nuclear accumulation of T221A was much more pronounced in G2/M phase. These results suggest that the phosphorylation of rpS3 by Cdk1 occurs at Thr221 during G2/M phase and, moreover, that this event is important for nuclear accumulation of rpS3.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • CDC2 Protein Kinase
  • Cell Division*
  • Cell Nucleus / metabolism
  • Cyclin B / metabolism*
  • Cyclin-Dependent Kinases
  • G2 Phase*
  • HEK293 Cells
  • Humans
  • Phosphorylation
  • Phosphothreonine / metabolism
  • Protein Binding
  • Ribosomal Proteins / metabolism*

Substances

  • Cyclin B
  • Ribosomal Proteins
  • ribosomal protein S3
  • Phosphothreonine
  • CDC2 Protein Kinase
  • CDK1 protein, human
  • Cyclin-Dependent Kinases