Vasopressin stimulates tyrosine phosphorylation by activation of pkc in the rat smooth muscle cell line, a-10

• Published in: Cell biology international Vol. 23; no. 3; pp. 195 - 201
• Main Authors: Gonzalez, CARLOS B, Reyes, Carlos E, Figueroa, Carlos D, Barra, Valeria, Troncoso, Silvia
• Format: Journal Article
• Language: English
• Published: Oxford, UK Elsevier Ltd 01.03.1999; Blackwell Publishing Ltd
• Subjects: Animals; Cell Line; Enzyme Activation - drug effects; Muscle, Smooth, Vascular - metabolism; peptide hormones; Phosphorylation; protein kinase C; Protein Kinase C - metabolism; protein phosphorylation; Rats; receptors; Signal Transduction - drug effects; Tyrosine - metabolism; vascular smooth muscle; Vasoconstrictor Agents - pharmacology; vasopressin; Vasopressins - pharmacology; vascular smooth muscle; peptide hormones; protein phosphorylation; receptors; protein kinase C; vasopressin
• ISSN: 1065-6995; 1095-8355
• DOI: 10.1006/cbir.1999.0343

Arginine vasopressin (AVP)-induced tyrosine phosphorylation was studied in a rat smooth muscle cell line, A-10, by western blotting, using a monoclonal antibody against phosphotyrosine. AVP stimulated the phosphorylation of several cellular proteins of molecular mass 60–130kDa in a time- and dose-dependent manner. Phosphorylation was mediated largely by V1receptor subtype since it was inhibited by selective V1antagonist and was only partially elicited by the V2agonist, desmopressin. Heterotrimeric G-proteins seemed to be involved in the phosphorylation mechanism because fluoraluminates, an activator of heterotrimeric G-proteins (and thus an uncoupler of the receptor–G-protein interaction) inhibited the AVP-induced phosphorylation. The protein kinase C (PKC) inhibitors: staurosporine, H7 and GF109203X are able to block the AVP-stimulated phosphorylation. The last of these has been shown to be one of the most selective inhibitors of PKC. These results indicate that PKC is upstream of the phosphorylation, a motion which is supported by the fact that the AVP-stimulated phosphorylation was downregulated by phorbol esters.