Electroporation of pp60c-src antibodies inhibits the angiotensin II activation of phospholipase C-gamma 1 in rat aortic smooth muscle cells.
Our previous study has shown that angiotensin II induces the rapid tyrosine phosphorylation and activation of phospholipase C-gamma 1 in cultured rat aortic smooth muscle (RASM) cells (Marrero, M.B., Paxton, W.G., Duff, J. L., Berk, B. C., and Bernstein, K. E. (1994) J. Biol. Chem, 269, 10935-10939). This signaling pathway is initiated by ligand binding to the AT1 receptor, a cell surface G protein-coupled receptor. Antibodies to pp60c-src were introduced into RASM cells by electroporation. Angiotensin II-stimulated tyrosine phosphorylation of phospholipase C-gamma 1 was eliminated by the anti-pp60c-src antibodies but not by anti-mouse IgG or bovine serum albumin. Angiotensin II also induced the rapid tyrosine phosphorylation of pp120, a known pp60c-src kinase substrate, and this phosphorylation was also specifically inhibited by anti-pp60c-src antibodies. Electroporation of RASM cells with anti-pp60c-src antibodies had no effect on platelet-derived growth factor-stimulated tyrosine phosphorylation of PLC-gamma 1. Anti-pp60c-src also reduced the angiotensin II-stimulated inositol 1,4,5-trisphosphate production by 78%, while it had no effect on the platelet-derived growth factor-stimulated inositol 1,4,5-trisphosphate production. These data provide the first evidence for a direct involvement of pp60c-src kinase in angiotensin II-mediated PLC-gamma 1 phosphorylation and activation. Furthermore, it also describes a pathway in which a seven-transmembrane receptor can stimulate an intracellular tyrosine kinase.
Marrero
M B
MB
Department of Pathology, Emory University, Atlanta, Georgia 30322, USA.
Schieffer
B
B
Paxton
W G
WG
Schieffer
E
E
Bernstein
K E
KE
D000804:Angiotensin II / Q000037:antagonists & inhibitors*; D000818:Animals; D000906:Antibodies / Q000276:immunology*; D001011:Aorta / Q000201:enzymology; D002478:Cells, Cultured; D018274:Electroporation; D005434:Flow Cytometry; D015544:Inositol 1,4,5-Trisphosphate / Q000096:biosynthesis; D009131:Muscle, Smooth, Vascular / Q000201:enzymology*; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000276:immunology / Q000502:physiology*; D051381:Rats; D010738:Type C Phospholipases / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism
D000906:Antibodies; D010982:Platelet-Derived Growth Factor; D000804:Angiotensin II; D014443:Tyrosine; D015544:Inositol 1,4,5-Trisphosphate; D016392:Proto-Oncogene Proteins pp60(c-src); D010738:Type C Phospholipases