Roberts D D, Rao C N, Magnani J L, Spitalnik S L, Liotta L A, Ginsburg V
Proc Natl Acad Sci U S A. 1985 Mar;82(5):1306-10. doi: 10.1073/pnas.82.5.1306.
Previous studies of the agglutination of erythrocytes by the basement membrane glycoprotein laminin have suggested that laminin binds to gangliosides [Kennedy, D.W., Rohrbach, D.H., Martin, G.R., Momoi, T. & Yamada, K.M. (1983) J. Cell. Physiol. 114, 257-262]. Based on the following evidence, however, we find that laminin binds specifically to sulfatides, not gangliosides. Monogalactosyl sulfatides, purified from sheep erythrocytes with a yield of 4.3 mg/kg of packed cells, bound laminin with high affinity as did authentic bovine brain sulfatide (galactosylceramide-I3-sulfate). The binding activity of these lipids and of total erythrocyte lipids was stable to alkali and neuraminidase treatment but labile to dilute acid under conditions that destroy sulfatides but not gangliosides. Of various glycolipid and phospholipid standards tested, only sulfatides bound laminin with high affinity. Sulfatide binding and agglutinating activities of proteolytic fragments of laminin indicated that the globular end regions of the 200-kDa subunits are required for both activities. Thus, monogalactosylsulfatides, and possibly other more complex sulfated glycolipids, are probably involved in the agglutination of erythrocytes. These results also suggest a physiological function of sulfatides in cell adhesion. The agglutination of erythrocytes by fibronectin is also inhibited by gangliosides [Yamada, K.M., Kennedy, D.W., Grotendorst, G.R. & Momoi, T. (1981) J. Cell. Physiol. 109, 343-351]. Fibronectin, however, did not bind to sulfatides with high affinity but rather bound with low affinity to all anionic lipids tested, including phospholipids, gangliosides, and sulfatides.
以往关于基底膜糖蛋白层粘连蛋白对红细胞凝集作用的研究表明，层粘连蛋白与神经节苷脂结合[肯尼迪，D.W.，罗尔巴赫，D.H.，马丁，G.R.，莫莫伊，T. & 山田，K.M.（1983年）《细胞生理学杂志》114卷，257 - 262页]。然而，基于以下证据，我们发现层粘连蛋白特异性结合硫脂，而非神经节苷脂。从绵羊红细胞中纯化得到的单半乳糖基硫脂，每千克压实细胞的产量为4.3毫克，它与层粘连蛋白的结合亲和力很高，正宗的牛脑硫脂（半乳糖基神经酰胺 - I3 - 硫酸盐）也是如此。这些脂质以及总红细胞脂质的结合活性对碱和神经氨酸酶处理稳定，但在破坏硫脂而非神经节苷脂的条件下，对稀酸不稳定。在所测试的各种糖脂和磷脂标准品中，只有硫脂与层粘连蛋白有高亲和力结合。层粘连蛋白蛋白水解片段的硫脂结合和凝集活性表明，200 kDa亚基的球状末端区域对这两种活性都是必需的。因此，单半乳糖基硫脂，以及可能其他更复杂的硫酸化糖脂，可能参与了红细胞的凝集。这些结果也提示了硫脂在细胞黏附中的生理功能。纤连蛋白对红细胞的凝集作用也受到神经节苷脂的抑制[山田，K.M.，肯尼迪，D.W.，格罗滕多斯特，G.R. & 莫莫伊，T.（1981年）《细胞生理学杂志》109卷，343 - 351页]。然而，纤连蛋白与硫脂的结合亲和力不高，而是与所测试的所有阴离子脂质（包括磷脂、神经节苷脂和硫脂）有低亲和力结合。
