Phorbol myristic acetate (PMA) induced protein kinase C translocation in LLC-PK₁ PIG kidney cells

Activation of protein kinase C (PKC) is suggested to play an important regulatory role in the renal water reabsorption. However, the identity of isoform(s) of PKC nor the mechanism of action are fully elucidated. In LLC-PK₁ kidney cell-line, only the PKCα form but not the β or γ forms were detected by immunoblotting. Furthermore, the distribution of PKCα after stimulation with PMA (100 nM). a potent activator of PKC. in the cytosol and particulate fractions (CF and PF) was studied utilizing immunoblotting. Over a period of time (15-60 minutes), there was a relocalization of PKCα from the CF to the PF. At 60 minutes, PKCα was almost absent from the cytosol and predominantly in the particulate fraction. 4-α-didecanoyl phorbol acetate, an inactive form of PMA, tailed to induce translocation of PKCα. Thus, a translocation of the PKCα isoform from the cytosol to the plasma membrane appears to occur in these renal cells. These results suggest that the α-isoform of PKC is present in l.I.C-PK₁ ceils and it may play a role in regulating water reabsorption.