Calphostin C induces selective disassembly of the Golgi complex by a protein kinase C-independent mechanism.
Intact cells incubated with calphostin C, an inhibitor of the regulatory domain of protein kinase C, showed fragmentation and dispersal of the Golgi complex by a light-dependent mechanism. At the ultrastructural level Golgi stacks were replaced by clusters of vesicles and short tubules that resembled the Golgi remnants present in control mitotic cells. Vesicle-mediated transport processes along both the exocytic and endocytic routes were also inhibited by calphostin C treatment. Golgi disassembly, however, was not due to protein kinase C inhibition since several inhibitors of the catalytic domain did not cause a similar effect. In contrast, pretreatment with phorbol 12-myristate 13-acetate partly protected the Golgi complex from disassembly by calphostin C. The in vitro effect was shown to be reversible, required both cytosol and ATP and it was inhibited by pretreatment of the Golgi membranes with trypsin but not with high salt. These results suggest the interaction of calphostin C with a structural Golgi protein containing a phorbol ester-binding domain and necessary for the stability of this organelle during interphase.
Department of Cell Biology, Faculty of Biology, University of Seville, Spain.
M
M
Alonso
M
M
Muñiz
C
C
Hall
A
A
Velasco
J
J
Hidalgo
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002417:Cattle; D002460:Cell Line; D020848:Chimerin 1; D004721:Endoplasmic Reticulum / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006056:Golgi Apparatus / Q000187:drug effects* / Q000378:metabolism* / Q000648:ultrastructure; D066298:In Vitro Techniques; D008027:Light; D008854:Microscopy, Electron; D009281:Naphthalenes / Q000494:pharmacology*; D009419:Nerve Tissue Proteins / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D051381:Rats; D013755:Tetradecanoylphorbol Acetate / Q000378:metabolism / Q000494:pharmacology
D020848:Chimerin 1; D004791:Enzyme Inhibitors; D009281:Naphthalenes; D009419:Nerve Tissue Proteins; D000255:Adenosine Triphosphate; D011493:Protein Kinase C; C058819:calphostin C; D013755:Tetradecanoylphorbol Acetate