Nitric Oxide Stimulates Tyrosine Phosphorylation of p125FAK and Paxillin in Rat Pancreatic Acini

Abstract

Some of the effects of several oncogenes, integrins, growth factors, and neuropeptides are mediated by tyrosine phosphorylation of the non-receptor tyrosine kinase p125FAK and the cytoskeletal protein paxillin. We have demonstrated that different stimuli cause tyrosine phosphorylation of p125FAK and paxillin in rat pancreatic acini. The aim of the present study was to determine whether exogenous NO activates this pathway. We demonstrate that in isolated rat pancreatic acini, a NO donor, sodium nitroprusside (SNP) stimulates, in a dose- and time-dependent way, tyrosine phosphorylation of p125FAK and paxillin. The same effects could be observed after incubating acini with 8-Br-cGMP. Moreover, the stimulation caused by SNP was completely abolished by two different guanylyl cyclase inhibitors, methylene blue, and LY-83583. These inhibitors also diminished unstimulated phosphorylation of p125FAK and paxillin. We conclude that in rat pancreatic acini exogenous NO causes p125FAK and paxillin tyrosine phosphorylation that is mediated by a guanylyl cyclase-dependent pathway.