Influence of various domains of protein kinase C ∈ on its PMA-induced translocation from the golgi to the plasma membrane

Subcellular redistribution (translocation) was initiated by treatment of NIH 3T3 cells overexpressing different epitope-tagged fragments of PKC∈ with PMA, and was analyzed by immunocytochemistry. The PMA-induced translocation of holo PKC∈, as well as fragments ∈2 (zinc finger domain + pseudosubstrate domain) and ∈7 (zinc finger domain + hinge region) from the Golgi to the plasma membrane was rapid (<10 min), while translocation of fragment ∈3 (zinc finger domain) was much slower (30-60 min). These results, combined with results of studies carried out at 20°C to inhibit exocytotic vesicle traffic, indicated that PMA-induced translocation from the Golgi to the plasma membrane may proceed by two distinct mechanisms: a rapid, vesicle independent process noted with holo PKC∈ (which requires the presence of the pseudosubstrate and/or hinge regions), and a slow, vesicle-dependent pathway observed with the zinc finger fragment.