Integrin-linked tyrosine phosphorylation increases membrane association of protein kinase C alpha in pancreatic acinar cells.

Ligation of beta 1 integrin receptors resulted in increased tyrosine phosphorylation of at least five proteins (Mrest = 110, 85, 55, 30 and 24 kD) from rat pancreatic acinar cells. Increased protein kinase C (PKC) activity and elevated amounts of immunoreactive PKC alpha were demonstrated in membrane fractions from integrin-ligated acinar cells. Membrane translocation of PKC alpha was confirmed using scanning confocal laser microscopy in immunocytochemical preparations of acinar cells following beta 1 integrin ligation. These studies establish the presence of a beta 1 integrin-linked protein tyrosine phosphorylation system in exocrine pancreatic cells and provide evidence for integrative activity of this system with PKC, a primary signalling pathway of central importance in these cells.