Martini F, Riondino S, Pignatelli P, Gazzaniga P P, Ferroni P, Lenti L
Laboratory of Platelet Pathophysiology, Department of Experimental Medicine and Pathology, University of Rome La Sapienza, Viale Regina Elena 324, 00161 Rome, Italy.
Biochim Biophys Acta. 2002 Aug 8;1583(3):297-304. doi: 10.1016/s1388-1981(02)00250-0.
Gangliosides are sialic acid-containing glycosphingolipids present in the outer leaflet of the plasma membrane of many cell types where they modulate adhesive processes. The main population of glycolipids in resting platelets is represented by ganglioside M3 (GM3). It has been demonstrated that following platelet activation ganglioside D3 (GD3) is rapidly formed from the GM3 pool. The present study was designed to evaluate the link between platelet activation and GD3 expression and to verify whether this ganglioside might play a role in modulating signal transduction events. Our results suggest that following platelet activation, GD3 is rapidly expressed on the platelet surface and internalised to the cytoskeleton where it transiently associates first with the Src family tyrosine kinase Lyn then with the Fc receptor gamma chain. This sequence of events ultimately leads to an enhanced CD32 (the Fc receptor isoform present in platelets) expression on the platelet membrane. These data drive us to speculate that GD3 might act as second messenger in the activatory cascade, which leads to CD32 expression and triggers platelet adhesion and spreading to the subendothelial matrix.
神经节苷脂是一类含唾液酸的糖鞘脂，存在于许多细胞类型质膜的外层小叶中，在那里它们调节黏附过程。静息血小板中糖脂的主要成分是神经节苷脂M3（GM3）。已经证明，血小板激活后，神经节苷脂D3（GD3）会迅速从GM3库中形成。本研究旨在评估血小板激活与GD3表达之间的联系，并验证这种神经节苷脂是否可能在调节信号转导事件中发挥作用。我们的结果表明，血小板激活后，GD3迅速在血小板表面表达并内化到细胞骨架中，在那里它首先与Src家族酪氨酸激酶Lyn短暂结合，然后与Fc受体γ链结合。这一系列事件最终导致血小板膜上CD32（血小板中存在的Fc受体异构体）表达增强。这些数据促使我们推测，GD3可能作为激活级联反应中的第二信使，导致CD32表达，并触发血小板黏附并铺展到内皮下基质。
