Influence of various domains of protein kinase C epsilon 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 epsilon with PMA, and was analyzed by immunocytochemistry. The PMA-induced translocation of holo PKC epsilon, as well as fragments epsilon 2 (zinc finger domain + pseudosubstrate domain) and epsilon 7 (zinc finger domain + hinge region) from the Golgi to the plasma membrane was rapid (<10 min), while translocation of fragment epsilon 3 (zinc finger domain) was much slower (30-60 min). These results, combined with results of studies carried out at 20 degrees 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 epsilon (which requires the presence of the pseudosubstrate and/or hinge regions), and a slow, vesicle-dependent pathway observed with the zinc finger fragment.