Sphingosine 1-phosphate is released from the cytosol of rat platelets in a carrier-mediated manner

Journal of Lipid Research

Takahiro Hirata¹  Takamitsu Sano²  Tsuyoshi Nishi³  Akihito Yamaguchi³  Akio Kihara⁴  Yasuyuki Igarashi⁵  Nobuyoshi Kobayashi⁵ 

[1] Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Corporation, Saitama, Japan;Department of Biomembrane and Biofunctional Chemistry, Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita 12-jo, Nishi 6-choume, Kita-ku, Sapporo, Hokkaido 060-0812, Japan;Graduate School of Pharmaceutical Sciences, Osaka University, Suita-shi, Osaka 565-0871, Japan;Precursory Research for Embryonic Science and Technology(PRESTO), Japan Science and Technology Corporation, Saitama, Japan;Department of Cell Membrane Biology, Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki-shi, Osaka 567-0047, Japan;

关键词: ATP binding cassette transporter;    flip-flop;    lipid mediator;    streptolysin O;    α-toxin;   

DOI  :  

来源: DOAJ

【 摘 要 】

Sphingosine 1-phosphate (S1P) is accumulated in platelets and released on stimulation by thrombin or Ca2+. Thrombin-stimulated S1P release was inhibited by staurosporin, whereas Ca2+-stimulated release was not. When the platelet plasma membrane was permeabilized with streptolysin O (SLO), S1P leaked out with cytosol markers, whereas granular markers remained in the platelets. The SLO-induced S1P leakage required BSA, probably for solubilization of S1P in the medium. These results indicate that S1P is localized in the inner leaflet of the plasma membrane and that its release is a carrier-mediated process. We also used alpha-toxin (ATX), which makes smaller pores in the plasma membrane than SLO and depletes cytosolic ATP without BSA-dependent S1P leakage. The addition of ATP drove S1P release from ATX platelets. The ATP-driven S1P release from ATX platelets was greatly enhanced by thrombin. An ATP binding cassette transporter inhibitor, glyburide, prevents ATP- and thrombin-induced S1P release from platelets. Ca2+ also stimulated S1P release from ATX platelets without ATP, whereas the Ca2+-induced release was not inhibited by glyburide. Our results indicate that two independent S1P release systems might exist in the platelet plasma membrane, an ATP-dependent system stimulated by thrombin and an ATP-independent system stimulated by Ca2+.

【 授权许可】

Unknown