Increase in cytoskeletal actin induced by inositol 1,4-bisphosphate in saponin-permeated pig platelets.
Inositol 1,4-bisphosphate (IP2) which rapidly accumulates during cell activation, strongly stimulates an increase in cytoskeletal actin in saponin-permeated platelets, and the effect is insensitive to 5'-Chloro-5'-deoxyadenosine. Within 10 s, the amount of cytoskeletal actin in platelets rapidly increases by 41%, and then slowly increases further. IP2 induces the increase in cytoskeletal actin in a dose-dependent manner. The half-maximal effect requires approximately 2 microM of IP2. Inositol 1,4,5- triphosphate, the messenger for Ca2+ release, causes the increase in cytoskeletal actin, but is less effective than IP2. Inositol 1-monophosphate and inositol 2-monophosphate have no effect on cytoskeletal actin. Phorbol 12-myristate 13-acetate, which has been shown to activate IP3 5'-phosphatase through protein kinase C, stimulates the increase in cytoskeletal actin. Spermine, an inhibitor of IP3 5'-phosphatase, inhibits the thrombin stimulated increase in cytoskeletal actin. These results suggest that IP2 may be a messenger that controls the organization of actin filaments during cell activation. This study presents the first evidence for IP2 as a messenger during cell activation.
Huang
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Department of Medical Biochemistry, Guangdong Medical College, Zhanjiang, P.R. China.
Liang
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NC
D000199:Actins / Q000378:metabolism*; D000818:Animals; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D002463:Cell Membrane Permeability / Q000187:drug effects; D017338:Cladribine / Q000494:pharmacology; D003599:Cytoskeleton / Q000187:drug effects* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D007295:Inositol Phosphates / Q000494:pharmacology*; D015539:Platelet Activation / Q000187:drug effects*; D011108:Polymers; D012503:Saponins / Q000494:pharmacology; D015290:Second Messenger Systems; D013096:Spermine / Q000494:pharmacology; D013552:Swine; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013917:Thrombin / Q000494:pharmacology
D000199:Actins; D007295:Inositol Phosphates; D011108:Polymers; D012503:Saponins; D013096:Spermine; C044259:inositol 1,4-bis(phosphate); D017338:Cladribine; C044739:5'-chloro-5'-deoxyadenosine; D013917:Thrombin; D013755:Tetradecanoylphorbol Acetate