Actin cytoskeleton of resting bovine platelets.
Actin filaments in resting discoid bovine platelets were examined by fluorescence and electron microscopy. Rhodamine-phalloidin staining patterns showed a characteristic wheel-like structure which consisted of a central small circle connected by several radial spokes to a large peripheral circle. This wheel-like structure was composed of actin filaments forming a characteristic arrowhead structure with heavy meromyosin from muscle. Actin filaments were densely arrayed in parallel with a marginal microtubule band and radiated out from the center to the periphery. Platelets treated with colchicine lost their marginal microtubule band but retained their wheel-like structure and normal discoid form. Cytochalasin B disrupted the wheel-like structure but not the marginal microtubule band or the normal discoid form. After simultaneous treatment with both cytochalasin B and colchicine, platelets lost their discoid shape. These results suggest that actin filaments and microtubules both play important roles in the maintenance of the discoid shape of resting bovine platelets.
Takeuchi
K
K
Department of Biology, Faculty of Science, Osaka University, Japan.
Kuroda
K
K
Ishigami
M
M
Nakamura
T
T
D000199:Actins / Q000032:analysis*; D000818:Animals; D001792:Blood Platelets / Q000187:drug effects / Q000648:ultrastructure*; D002417:Cattle; D003078:Colchicine / Q000494:pharmacology; D003571:Cytochalasin B / Q000494:pharmacology; D003599:Cytoskeleton / Q000648:ultrastructure*; D016650:Fluorescein-5-isothiocyanate; D005452:Fluoresceins; D005455:Fluorescent Antibody Technique; D005456:Fluorescent Dyes; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D010590:Phalloidine; D012235:Rhodamines; D013861:Thiocyanates; D014404:Tubulin / Q000032:analysis
D000199:Actins; D005452:Fluoresceins; D005456:Fluorescent Dyes; D012235:Rhodamines; D013861:Thiocyanates; D014404:Tubulin; D010590:Phalloidine; D003571:Cytochalasin B; D016650:Fluorescein-5-isothiocyanate; D003078:Colchicine