McEver R P
St. Francis Medical Research Institute, University of Oklahoma Health Sciences Center, Oklahoma City 73104.
Blood Cells. 1990;16(1):73-80; discussion 80-3.
GMP-140 is an integral membrane glycoprotein with an apparent Mr of 140,000 located in secretory granules of human platelets and endothelial cells. When these cells are stimulated, the protein is rapidly redistributed to the plasma membrane; therefore, monoclonal antibodies to GMP-140 are useful markers of activated platelets and endothelium. GMP-140 is cysteine-rich and heavily glycosylated. The cDNA-derived amino acid sequence indicates that it contains a number of modular domains that are likely to fold independently. Beginning at the N-terminus, these comprise a "lectin" domain, an "EGF" domain, nine tandem consensus repeats similar to those in complement-binding proteins, a transmembrane domain, and a cytoplasmic tail. Some cDNAs also predict variant forms of GMP-140, including a putative soluble form lacking the transmembrane domain that appears to arise from alternative splicing of mRNA. The domain organization of GMP-140 is strikingly similar to two other vascular cell surface structures: ELAM-1, a cytokine-inducible endothelial cell receptor that binds neutrophils, and a lymphocyte-homing receptor that mediates the adherence of lymphocytes to high endothelial venules of peripheral lymph nodes. These "selectins" constitute a new gene family of receptors with related structure and potentially related function.
GMP - 140是一种膜整合糖蛋白，表观分子量为140,000，存在于人类血小板和内皮细胞的分泌颗粒中。当这些细胞受到刺激时，该蛋白会迅速重新分布到质膜；因此，针对GMP - 140的单克隆抗体是活化血小板和内皮的有用标志物。GMP - 140富含半胱氨酸且高度糖基化。cDNA推导的氨基酸序列表明它包含许多可能独立折叠的模块化结构域。从N端开始，这些结构域包括一个“凝集素”结构域、一个“表皮生长因子”（EGF）结构域、九个与补体结合蛋白中的重复序列相似的串联共有重复序列、一个跨膜结构域和一个胞质尾。一些cDNA还预测了GMP - 140的变体形式，包括一种推测的缺乏跨膜结构域的可溶性形式，它似乎是由mRNA的可变剪接产生的。GMP - 140的结构域组织与另外两种血管细胞表面结构惊人地相似：ELAM - 1，一种可被细胞因子诱导的结合中性粒细胞的内皮细胞受体，以及一种介导淋巴细胞与外周淋巴结高内皮微静脉黏附的淋巴细胞归巢受体。这些“选择素”构成了一个具有相关结构和潜在相关功能的受体新基因家族。
