Effect of Insulin and phorbol esters on MARKS phosphorylation in rat adipocytes, rat soleus muscle and BC3H-1 myocytes

membrane-associated protein kinase C (PKC) in rat adipocytes [1,2]. These increases appear to be due to translocation of PKC from cytosol to the membrane fraction, a process that may reflect activation of the enzyme. Insulin-induced increases in membraneassociated PKC-dependent phosphorylation of histone Ills [1] and a synthetic peptide fragment of glycogen synthase [2] have been observed in the above-cited adipocyte studies, but these enzyme assays do not provide insight into which PKC isoform(s) is (are) translocated. We have previously reported [1] that immunoreactive PKC-? is translocated in response to treatment of rat adipocytes with insulin and phorbol 12-myristate 13- acetate (PMA). In the present paper, we have characterized the PKC profile in rat adipocytes and report on the effects of insulin and PMA on the subcellular distribution of PKC isoforms, namely ax, fi, y, 8, e a