Electron microscopic analysis of lipid clusters and membrane proteins in plasma membrane.

我们使用最近开发的选择性结合特定脂类或脂簇的多肽/蛋白质来检测跨双层和横向脂膜中的脂类分布。脂质体实验表明，即使在膜浓度低至1mol%的情况下，探针也能有效地检测到脂质，并且探针与模拟叶内外脂肪环境的模型膜结合类似。接下来，我们检测了静息和凝血酶刺激的血小板以及高度促凝血的血小板微粒中神经鞘磷脂和磷脂酰丝氨酸的分布。我们的结果表明，在凝血酶激活的血小板中，被打乱的膜以微粒的形式被选择性地释放，这表明内部小叶中的磷脂酰丝氨酸暴露在外部触发了血小板的囊泡形成。

We examined transbilayer and lateral lipid distribution in plasma membrane using recently developed peptide/proteins that selectively bind specific lipids or lipid clusters. The liposome experiments demonstrated that the lipids were effectively detected by the probes even when the membrane concentration was as low as 1 mol%, and the probes bound similarly to the model membranes that mimic outer or inner leaflet lipid environment.Next, we examined the distribution of sphingomyelin and phosphatidylserine in resting and thrombin-stimulated platelets as well as platelet microparticles that are highly procoagulant. Our results indicate that the scrambled membranes are selectively released in the form of microparticles in thrombin-activated platelets and suggest the idea that the exposure of phosphatidylserine in inner leaflet to the outer triggers the vesiculation of platelets.