Protein-tyrosine phosphatase-alpha and Src functionally link focal adhesions to the endoplasmic reticulum to mediate interleukin-1-induced Ca2+ signaling

J Biol Chem. 2009 Jul 31;284(31):20763-72. doi: 10.1074/jbc.M808828200. Epub 2009 Jun 3.

Abstract

Calcium (Ca2+) signaling by the pro-inflammatory cytokine interleukin-1 (IL-1) is dependent on focal adhesions, which contain diverse structural and signaling proteins including protein phosphatases. We examined here the role of protein-tyrosine phosphatase (PTP) alpha in regulating IL-1-induced Ca2+ signaling in fibroblasts. IL-1 promoted recruitment of PTPalpha to focal adhesions and endoplasmic reticulum (ER) fractions, as well as tyrosine phosphorylation of the ER Ca2+ release channel IP3R. In response to IL-1, catalytically active PTPalpha was required for Ca2+ release from the ER, Src-dependent phosphorylation of IP3R1 and accumulation of IP3R1 in focal adhesions. In pulldown assays and immunoprecipitations PTPalpha was required for the association of PTPalpha with IP3R1 and c-Src, and this association was increased by IL-1. Collectively, these data indicate that PTPalpha acts as an adaptor to mediate functional links between focal adhesions and the ER that enable IL-1-induced Ca2+ signaling.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Calcium Signaling / drug effects*
  • Cells, Cultured
  • Endoplasmic Reticulum / drug effects
  • Endoplasmic Reticulum / enzymology*
  • Focal Adhesions / drug effects
  • Focal Adhesions / enzymology*
  • Humans
  • Inositol 1,4,5-Trisphosphate Receptors / metabolism
  • Interleukin-1 / pharmacology*
  • Mice
  • Phosphotyrosine / metabolism
  • Protein Binding / drug effects
  • Rats
  • Receptor-Like Protein Tyrosine Phosphatases, Class 4 / metabolism*
  • src-Family Kinases / metabolism*

Substances

  • Inositol 1,4,5-Trisphosphate Receptors
  • Interleukin-1
  • Phosphotyrosine
  • src-Family Kinases
  • Receptor-Like Protein Tyrosine Phosphatases, Class 4