PKA regulates calcineurin function through the phosphorylation of RCAN1: identification of a novel phosphorylation site

Biochem Biophys Res Commun. 2015 Apr 17;459(4):604-9. doi: 10.1016/j.bbrc.2015.02.155. Epub 2015 Mar 7.

Abstract

Calcineurin is a calcium/calmodulin-dependent phosphatase that has been implicated in T cell activation through the induction of nuclear factors of activated T cells (NFAT). We have previously suggested that endogenous regulator of calcineurin (RCAN1, also known as DSCR1) is targeted by protein kinase A (PKA) for the control of calcineurin activity. In the present study, we characterized the PKA-mediated phosphorylation site in RCAN1 by mass spectrometric analysis and revealed that PKA directly phosphorylated RCAN1 at the Ser 93. PKA-induced phosphorylation and the increase in the half-life of the RCAN1 protein were prevented by the substitution of Ser 93 with Ala (S93A). Furthermore, the PKA-mediated phosphorylation of RCAN1 at Ser 93 potentiated the inhibition of calcineurin-dependent pro-inflammatory cytokine gene expression by RCAN1. Our results suggest the presence of a novel phosphorylation site in RCAN1 and that its phosphorylation influences calcineurin-dependent inflammatory target gene expression.

Keywords: Calcineurin; Inflammation; PKA; Phosphorylation; RCAN1.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Calcineurin / physiology*
  • Cyclic AMP-Dependent Protein Kinases / metabolism*
  • DNA-Binding Proteins
  • HEK293 Cells
  • Humans
  • Intracellular Signaling Peptides and Proteins / chemistry
  • Intracellular Signaling Peptides and Proteins / metabolism*
  • Molecular Sequence Data
  • Muscle Proteins / chemistry
  • Muscle Proteins / metabolism*
  • Phosphorylation

Substances

  • DNA-Binding Proteins
  • Intracellular Signaling Peptides and Proteins
  • Muscle Proteins
  • RCAN1 protein, human
  • Cyclic AMP-Dependent Protein Kinases
  • Calcineurin