Immediate-early response 5 (IER5) interacts with protein phosphatase 2A and regulates the phosphorylation of ribosomal protein S6 kinase and heat shock factor 1

FEBS Lett. 2015 Nov 30;589(23):3679-85. doi: 10.1016/j.febslet.2015.10.013. Epub 2015 Oct 20.

Abstract

Immediate-early response 5 (IER5) is a growth factor-inducible protein with homology to the N-terminus of IER2. Deletion analysis shows that a large region of IER5, including the N-terminal region, is involved in cell growth and stress resistance. The N-terminal region mediates IER5 oligomerization and binding to the B55 regulatory subunit of protein phosphatase 2A (PP2A). IER5 physically interacts with the PP2A target proteins ribosomal protein S6 kinase (S6K) and heat shock factor 1 (HSF1), and the interactions are essential for the reduced phosphorylation of S6K and HSF1. Our data indicate that oligomeric IER5 regulates PP2A activity and cell growth.

Keywords: Heat shock factor 1; Immediate-early response 5; Phosphorylation; Protein phosphatase 2A; S6 kinase.

MeSH terms

  • Cell Proliferation
  • DNA-Binding Proteins / metabolism*
  • HeLa Cells
  • Heat Shock Transcription Factors
  • Humans
  • Immediate-Early Proteins / chemistry
  • Immediate-Early Proteins / metabolism*
  • Phosphorylation
  • Protein Binding
  • Protein Multimerization
  • Protein Phosphatase 2 / chemistry
  • Protein Phosphatase 2 / metabolism*
  • Protein Structure, Quaternary
  • Protein Subunits / metabolism
  • Ribosomal Protein S6 Kinases / metabolism*
  • Transcription Factors / metabolism*

Substances

  • DNA-Binding Proteins
  • HSF1 protein, human
  • Heat Shock Transcription Factors
  • Immediate-Early Proteins
  • Protein Subunits
  • Transcription Factors
  • Ribosomal Protein S6 Kinases
  • Protein Phosphatase 2