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 hole PKC epsilon, as well as fragments epsil on 2 (zinc finger domain + pseudosubstrate domain) and epsilon 7 (zinc finger domain + hinge region) from the Golgi to the plasma membrane w as rapid (<10 min), while translocation of fragment epsilon 3 (zinc fi nger 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 Gol gi to the plasma membrane may proceed by two distinct mechanisms: a ra pid, vesicle independent process noted with hole PKC epsilon (which re quires the presence of the pseudosubstrate and/or hinge regions), and a slow, vesicle-dependent pathway observed with the zinc finger fragme nt. (C) 1996 Academic Press, Inc.