神经鞘磷脂(SM)是哺乳动物细胞中的主要鞘脂。尽管SM富集在细胞质膜的外小叶中,在质膜和细胞内细胞器如内溶酶体的内小叶中也观察到脂质,高尔基体和原子核.假定SM与鞘糖脂(GSL)形成簇,胆固醇(Chol),和其他SM分子通过疏水相互作用和氢键键合。因此,由SM组成的不同集群,SM/Chol,生物膜中可能存在不同化学计量的SM/GSL和SM/GSL/Chol。此外,SM单体可以位于膜的富含甘油磷脂的区域中。最近开发的SM结合蛋白(SBP)区分了这些不同的SM组件。这里,我们总结了调节SBPs脂质结合特异性的内在因素和外在因素的影响,如脂质相和脂质密度,SBP对SM的识别。不同SBP的组合揭示了生物膜中SM结构域的异质性。
Sphingomyelin (SM) is a major sphingolipid in mammalian cells. Although SM is enriched in the outer leaflet of the cell plasma membrane, lipids are also observed in the inner leaflet of the plasma membrane and intracellular organelles such as endolysosomes, the Golgi apparatus and nuclei. SM is postulated to form clusters with glycosphingolipids (GSLs), cholesterol (Chol), and other SM molecules through hydrophobic interactions and hydrogen bonding. Thus, different clusters composed of SM, SM/Chol, SM/GSL and SM/GSL/Chol with different stoichiometries may exist in biomembranes. In addition, SM monomers may be located in the glycerophospholipid-rich areas of membranes. Recently developed SM-binding proteins (SBPs) distinguish these different SM assemblies. Here, we summarize the effects of intrinsic factors regulating the lipid-binding specificity of SBPs and extrinsic factors, such as the lipid phase and lipid density, on SM recognition by SBPs. The combination of different SBPs revealed the heterogeneity of SM domains in biomembranes.