The inhibitory effects of okadaic acid on platelet function

FEBS Letters

Higashihara, Masaaki²  Ikebe, Mitsuo³  Kurokawa, Kiyoshi²  Takahata, Kyoya¹ 

[1] Kureha Chemical Industry Co. Ltd., Shinjuku-ku, Tokyo 113, Japan;First Department of Internal Medicine, Faculty of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku 113, Japan;Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44187, USA

关键词: Platelet;    Phosphatase;    Okadaic acid;    Myosin light chain;   

DOI  :  10.1016/0014-5793(92)80768-C

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Okadaic acid (OA), a potent inhibitor of protein phosphatases type 1 and type 2A, inhibited thrombin-induced platelet aggregation (IC₅₀ = 0.8 μM), [¹⁴C]serotonin release and increase in intracellular Ca²⁺ ([Ca²⁺]_i) in the same dose dependence. In the absence of thrombin OA increased the phosphorylation of 50-kDa protein and 20-kDa myosin light chain (MLC20). The 50-kDa protein phosphorylation was accomplished within a shorter time period and at a lower concentration than was the MLC20, OA decreased the thrombin-induced phosphorylation of 47-kDa protein and MLC20, although phosphorylation of MLC20 reincreased at higher concentrations of OA (5−10 μM). Since type 2A phosphatase is more sensitive to OA than type 1, these results suggest that type 2A phosphatases are involved in the regulation of Ca²⁺ signaling in thrombin-induced platelet activation.

【 授权许可】

Unknown