Participation of a novel 88-kD protein in the biogenesis of murine class I histocompatibility molecules.
Participation of a novel 88-kD protein in the biogenesis of murine class I histocompatibility molecules.
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DOI：
10.1083/jcb.112.6.1099
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发表时间：
1991-03
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影响因子：
--
通讯作者：
Williams DB
中科院分区：
文献类型：
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作者：
Degen E;Williams DB
化学交联和凝胶渗透层析用于检测I类组织相容性分子生物发生的早期事件。我们发现，在三个小鼠肿瘤细胞系中，新合成的I类重链与一个88-kD的蛋白快速和定量地结合。该蛋白(P88)似乎不具有ASN连接的多糖，也不是丰富的ER蛋白GRP94。I-P88类复合体是瞬时存在的(t1/2=20-45min，取决于特定的I类重链)，多条证据表明，P88在内质网中时与复合体解离。当β2-微球蛋白与重链结合时不会触发解离(T1/2=2-5分钟)。然而，解离速率确实与所研究的特定I类分子的内质网到高尔基体转运的特征速率相关。因此，P88的解离可能是内质网向高尔基体转运的限速因素。I类分子结合抗原肽，显然是在内质网中，随后呈现给细胞表面的细胞毒性T淋巴细胞。P88在形成重链、β2-微球蛋白和多肽三元复合体的过程中，可促进多肽结合或保留内质网中的I类分子。
Chemical cross-linking and gel permeation chromatography were used to examine early events in the biogenesis of class I histocompatibility molecules. We show that newly synthesized class I heavy chains associate rapidly and quantitatively with an 88-kD protein in three murine tumor cell lines. This protein (p88) does not appear to possess Asn-linked glycans and it is not the abundant ER protein, GRP94. The class I-p88 complex exists transiently (t1/2 = 20-45 min depending on the specific class I heavy chain) and several lines of evidence suggest that p88 dissociates from the complex while still in the ER. Dissociation is not triggered upon binding of beta 2-microglobulin to the heavy chain (t1/2 = 2-5 min). However, the rate of dissociation does correlate with the characteristic rate of ER to Golgi transport for the particular class I molecule studied. Consequently, dissociation of p88 may be rate limiting for ER to Golgi transport. Class I molecules bind antigenic peptides, apparently in the ER, for subsequent presentation to cytotoxic T lymphocytes at the cell surface. p88 could promote peptide binding or it may retain class I molecules in the ER during formation of the ternary complex of heavy chain, beta 2- microglobulin, and peptide.