G13alpha-mediated PYK2 activation. PYK2 is a mediator of G13alpha -induced serum response element-dependent transcription.
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.
Shi
C S
CS
BCell Molecular Immunology Section, Laboratory of Immunoregulation, NIAID, National Institutes of Health, Bethesda, Maryland 20892-1876, USA.
Sinnarajah
S
S
Cho
H
H
Kozasa
T
T
Kehrl
J H
JH
D019943:Amino Acid Substitution; D000818:Animals; D019556:COS Cells; D051418:Focal Adhesion Kinase 2; D020558:GTP Phosphohydrolases / Q000378:metabolism; D044365:GTP-Binding Protein alpha Subunits, G12-G13; D017930:Genes, Reporter; D006367:HeLa Cells; D020962:Heterotrimeric GTP-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D008156:Luciferases / Q000235:genetics; D016297:Mutagenesis, Site-Directed; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000235:genetics* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D017384:Sequence Deletion; D014158:Transcription, Genetic; D014162:Transfection; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
D011994:Recombinant Proteins; D008156:Luciferases; D011505:Protein-Tyrosine Kinases; D051418:Focal Adhesion Kinase 2; D020558:GTP Phosphohydrolases; D044365:GTP-Binding Protein alpha Subunits, G12-G13; D020962:Heterotrimeric GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein