G13alpha-mediated PYK2 activation. PYK2 is a mediator of G13alpha -induced serum response element-dependent transcription

J Biol Chem. 2000 Aug 11;275(32):24470-6. doi: 10.1074/jbc.M908449199.

Abstract

G(12)alpha/G(13)alpha transduces signals from G-protein-coupled receptors to stimulate growth-promoting pathways and the early response gene c-fos. Within the c-fos promoter lies a key regulatory site, the serum response element (SRE). Here we show a critical role for the tyrosine kinase PYK2 in muscarinic receptor type 1 and G(12)alpha/G(13)alpha signaling to an SRE reporter gene. A kinase-inactivate form of PYK2 (PYK2 KD) inhibits muscarinic receptor type 1 signaling to the SRE and PYK2 itself triggers SRE reporter gene activation through a RhoA-dependent pathway. Placing PYK2 downstream of G-protein activation but upstream of RhoA, the expression of PYK2 KD blocks the activation of an SRE reporter gene by GTPase-deficient forms of G(12)alpha or G(13)alpha but not by RhoA. The GTPase-deficient form of G(13)alpha triggers PYK2 kinase activity and PYK2 tyrosine phosphorylation, and co-expression of the RGS domain of p115 RhoGEF inhibits both responses. Finally, we show that in vivo G(13)alpha, although not G(12)alpha, readily associates with PYK2. Thus, G-protein-coupled receptors via G(13)alpha activation can use PYK2 to link to SRE-dependent gene expression.

MeSH terms

  • Amino Acid Substitution
  • Animals
  • COS Cells
  • Focal Adhesion Kinase 2
  • GTP Phosphohydrolases / metabolism
  • GTP-Binding Protein alpha Subunits, G12-G13
  • Genes, Reporter
  • HeLa Cells
  • Heterotrimeric GTP-Binding Proteins / chemistry
  • Heterotrimeric GTP-Binding Proteins / metabolism*
  • Humans
  • Luciferases / genetics
  • Mutagenesis, Site-Directed
  • Phosphorylation
  • Protein-Tyrosine Kinases / genetics*
  • Protein-Tyrosine Kinases / metabolism*
  • Recombinant Proteins / metabolism
  • Sequence Deletion
  • Transcription, Genetic
  • Transfection
  • rhoA GTP-Binding Protein / metabolism

Substances

  • Recombinant Proteins
  • Luciferases
  • Protein-Tyrosine Kinases
  • Focal Adhesion Kinase 2
  • GTP Phosphohydrolases
  • GTP-Binding Protein alpha Subunits, G12-G13
  • Heterotrimeric GTP-Binding Proteins
  • rhoA GTP-Binding Protein