Protein kinase C-dependent supply of secretory granules to the plasma membrane.
To elucidate the mechanism for supplying secretory granules to the cell membrane, chromaffin cells isolated from the bovine adrenal medulla were observed by the evanescent wave microscopy after staining their granules with acridine orange. The secretory granules showed only a very small fluctuation, indicating their docking to the plasma membrane. The rate and range of movement increased greatly by application of botulinum toxin A or C. The number of secretory granules docked to the plasma membrane significantly decreased by botulinum toxin C. Conversely, the number increased greatly by activation of protein kinase C with phorbol 12,13-dibutyrate (PDBu). In the presence of an anti-actin reagent cytochalasin D, no increasing effect of PDBu on the number of docked granules was observed. While in the presence of an anti-mitotic reagent, colchicine, a clear increasing effect of PDBu was observed. The final step for supplying granules to the plasma membrane in endocrine cells is concluded to be mediated by a phosphorylation-dependent and actin-based transport system.
Tsuboi
T
T
Photon Medical Research Center, Hamamatsu University School of Medicine, 3600 Handa, Hamamatsu, 431-3192, Japan.
Kikuta
T
T
Warashina
A
A
Terakawa
S
S
D000165:Acridine Orange; D000199:Actins / Q000378:metabolism; D000818:Animals; D001905:Botulinum Toxins / Q000494:pharmacology; D019274:Botulinum Toxins, Type A / Q000494:pharmacology; D002417:Cattle; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology* / Q000648:ultrastructure*; D019439:Chromaffin Cells / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure*; D003078:Colchicine / Q000494:pharmacology; D015638:Cytochalasin D / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D005456:Fluorescent Dyes; D066298:In Vitro Techniques; D008856:Microscopy, Fluorescence; D009068:Movement / Q000187:drug effects; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism*; D022142:Secretory Vesicles / Q000187:drug effects / Q000201:enzymology* / Q000648:ultrastructure*
D000199:Actins; D005456:Fluorescent Dyes; D015638:Cytochalasin D; D015240:Phorbol 12,13-Dibutyrate; D011493:Protein Kinase C; D001905:Botulinum Toxins; D019274:Botulinum Toxins, Type A; D000165:Acridine Orange; C096324:botulinum toxin type C; D003078:Colchicine