Synaptic membrane glycoproteins gp65 and gp55 are new members of the immunoglobulin superfamily
Synaptic membrane glycoproteins gp65 and gp55 are new members of the immunoglobulin superfamily
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DOI：
10.1074/jbc.272.2.821
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发表时间：
1997-01-10
影响因子：
4.8
通讯作者：
Gundelfinger, ED
中科院分区：
文献类型：
--
作者：
Langnaese, K;Beesley, PW;Gundelfinger, ED
糖蛋白gp 65和gp 55是大鼠前脑突触膜的主要成分。两者均被单克隆抗体SMgp 65识别。我们用SMgp 65筛选了大鼠脑cDNA表达文库。分离出两组重叠cDNA，它们含有397和281个氨基酸的开放阅读框。推导的蛋白质是免疫球蛋白（IG）超家族的成员，分别含有三个和两个IG结构域。共同部分与神经皮素/basigin具有约40%的序列同一性。通过产生针对共同重组蛋白片段的新抗血清来确认蛋白质为gp 65和gp 55的身份。这些抗血清免疫沉淀gp 65和gp 55。此外，在用衣霉素处理的人293细胞中gp 65和gp 55 cDNA的表达导致产生与去糖基化gp 65和gp 55大小相同的非糖基化核心蛋白。北方分析表明，gp 65的成绩单是脑特异性的，而gp 55在大多数组织和细胞系的检查。在蛋白质水平上确认了组织分布，尽管不同组织之间gp 55的糖基化模式不同。原位杂交实验表明，一个共同的和一个gp 65特异性探针gp 65和gp 55转录在大鼠大脑中的差异表达。
Glycoproteins gp65 and gp55 are major components of synaptic membranes prepared from rat forebrain. Both are recognized by the monoclonal antibody SMgp65. We have used SMgp65 to screen a rat brain cDNA expression library. Two sets of overlapping cDNAs that contain open reading frames of 397 and 281 amino acids were isolated. The deduced proteins are members of the immunoglobulin (Ig) superfamily containing three and two Ig domains, respectively. The common part has similar to 40% sequence identity with neurothelin/basigin. The identity of the proteins as gp65 and gp55 was confirmed by production of new antisera against a common recombinant protein fragment. These antisera immunoprecipitate gp65 and gp55. Furthermore, expression of gp65 and gp55 cDNAs in human 293 cells treated with tunicamycin results in the production of unglycosylated core proteins of identical size to deglycosylated gp65 and gp55. Northern analysis revealed that gp65 transcripts are brain-specific, whereas gp55 is expressed in most tissues and cell lines examined. The tissue distribution was confirmed at the protein level though the pattern of glycosylation of gp55 varies between tissues. In situ hybridization experiments with a common and a gp65 specific probe suggest differential expression of gp65 and gp55 transcripts in the rat brain.