title: Phorbol myristate acetate stimulates microtubule and 10-nm filament extension and lysosome redistribution in mouse macrophages.
abstract: Phorbol myristate acetate (PMA) stimulates cell spreading and fluid-phase pinocytosis in mouse peritoneal macrophages. Colchicine (10(-5) M) and cytochalasin B (10(-5) M) abolish PMA stimulated pinocytosis but have little effect on cellular spreading (Phaire-Washington et al., 1980, J. Cell Biol., 86:634-640). We report here that PMA also alters the organization of the cytoskeleton and the distrubution of organelles in these cells. Neither control nor PMA-treated macrophages contain actin cables. PMA-treated resident thioglycolate-elicited macrophages exhibit beneath their substrate-adherent membranes many randomly distributed punctate foci that stain brightly for actin. The appearance and distribution of these actin-containing foci are not altered by colchicine (10(-5) M) or cytochalasin B (10(-5) M). In thioglycolate-elicited macrophages PMA causes the extension and radial organization of microtubules and 10-nm filaments and promotes the movement of secondary lysosomes from their perinuclear location to the peripheral cytoplasm. Depending upon the concentration of PMA used, 45-71% of thioglycolate-elicited macrophages and 32-44% of proteose-peptone-elicited macrophages and numerous lysosomes, radiating from the centrosphere region, arranged linearly along microtubule and 10-nm filament bundles. Colchicine (10(-5) M) and podophyllotoxin (10(-5) M) prevent the radial redistribution of microtubules, 10-nm filaments, and lysosomes in these cells. Cytochalasins B and D (10(-5) M) have no inhibitory effects on these processes. These findings indicate that microtubules and 10-nm filaments respond in a coordinated fashion to PMA and to agents that inhibit microtubule function; they suggest that these cytoskeletal elements regulate the movement and distribution of lysosomes in the macrophage cytoplasm.
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000199:Actins / Q000378:metabolism; D000818:Animals; D003572:Cytochalasins / Q000494:pharmacology; D003599:Cytoskeleton / Q000187:drug effects*; D008247:Lysosomes / Q000187:drug effects*; D008264:Macrophages / Q000187:drug effects* / Q000648:ultrastructure; D051379:Mice; D008870:Microtubules / Q000187:drug effects*; D008928:Mitochondria / Q000648:ultrastructure; D010704:Phorbols / Q000494:pharmacology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014404:Tubulin / Q000378:metabolism
chemical_list: D000199:Actins; D003572:Cytochalasins; D010704:Phorbols; D014404:Tubulin; D000135:Acid Phosphatase; D013755:Tetradecanoylphorbol Acetate