Phase specific association of heterotrimeric GTP-binding proteins with the actin-based cytoskeleton during thrombin receptor-mediated platelet activation.
Subcellular distribution of heterotrimeric GTP-binding proteins during thrombin receptor-mediated platelet activation was examined, revealing two phases of translocation to the cytoskeleton. A part of Gi2 alpha and Gs alpha shows first phase translocation to the low-speed pellet (15000 x g pellet) within 1 min after activation, suggesting involvement in platelet shape change or granule secretion. In the second phase, Gi2 alpha, Gs alpha, Gq alpha, and G beta translocate to the low-speed pellet, depending on platelet aggregation. These translocations correlated with the reorganization of the actin-cytoskeleton and were inhibited by cytochalasin D. Reconstitution experiments also revealed that G proteins are associated with the actin-cytoskeleton during platelet activation.
Ozawa
K
K
Department of Neurochemistry and Neuropharmacology, Biomedical Research Center, Osaka University Medical School, Japan.
Takahashi
M
M
Sobue
K
K
D000199:Actins / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D015638:Cytochalasin D / Q000494:pharmacology; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000494:pharmacology; D015539:Platelet Activation / Q000502:physiology*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000502:physiology; D018179:Receptors, Thrombin / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology
D000199:Actins; D009842:Oligopeptides; D010975:Platelet Aggregation Inhibitors; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D018179:Receptors, Thrombin; D015638:Cytochalasin D; C046617:arginyl-glycyl-aspartyl-serine; D019204:GTP-Binding Proteins