Is protein kinase C alpha (PKC alpha) involved in vasopressin-induced effects on LLC-PK1 pig kidney cells?

Abstract

The involvement of protein kinase C (PKC) in vasopressin-induced effects on renal water reabsorption is still unresolved. Activation of PKC can be detected by its translocation from the cytosol (C) to the plasma membrane (PM). In LLC-PK1 cells, the redistribution of PKC alpha, a predominant isoform of PKC detected, was studied utilizing western blotting after stimulation with vasopressin. Vasopressin (100 mU/ml) failed to induce a translocation of PKC alpha from the C to the PM. By contrast, phorbol myristate acetate (PMA, 200 nM), a potent activator of PKC, induced a relocalization of PKC alpha from the C to the PM. After 2 hours of treatment of cells with PMA, PKC alpha was predominantly detected in the PM and absent from the C. These results suggest that the signal transduction pathway of vasopressin in LLC-PK1 cells does not involve PKC alpha activation and translocation.