Immunocytochemical expression and localization of protein kinase C in bovine aortic endothelial cells

Total PKC activity in BAEC incubated for 24 hrs in either 10% serum (FBS) or serum-deprived media (SDM) was similar. However, most of the activity (69%) in the FBS group was detected in the particulate fraction, while it was mainly in the cystosolic fraction (66%) in the SDM group. By confocal microscopy, there was diffuse cytoplasmic localization of the antibodies to the α and β PKC isoforms. γ PKC was not detected. Treatment of FBS or SDM cells with a phorbol ester resulted in an increase in PKC activity with translocation to the particulate fraction. PKC α immunofluorescence redistributed to the perinuclear region whereas PKC β staining remained mostly cytosolic. Calphostin C, a PKC inhibitor, prevented the phorbol ester-induced increase in PKC activity and translocation.