Deverson E V, Powis S J, Morrice N A, Herberg J A, Trowsdale J, Butcher G W
Molecular Immunology Programme, The Babraham Institute, Cambridge, UK.
Genes Immun. 2001 Feb;2(1):48-51. doi: 10.1038/sj.gene.6363727.
During the assembly of major histocompatibility complex (MHC) class I molecules transient associations are formed with the endoplasmic reticulum resident chaperones calnexin and calreticulin, ERp57 oxidoreductase, and also with tapasin, the latter mediating binding of the class I molecules to the transporter associated with antigen processing (TAP). We report here the isolation of a cDNA encoding rat tapasin from a DA (RT1av1) library. The cDNA encodes a proline-rich (11.3%) polypeptide of 464 residues with a potential ER-retention KK motif at its COOH-terminus, and a predicted molecular mass of 48 kDa. Matrix-assisted laser-desorption ionisation (MALDI) mass spectrometry of peptides derived from in-gel tryptic digestion of a TAP-associated protein match regions of the predicted translation product. A species of the correct molecular mass and predicted pl was also identified in association with radiolabelled immunoprecipitates of the rat TAP complex analysed by two-dimensional gel electrophoresis. This confirms rat tapasin as a component of the rat MHC class I assembly complex.
在主要组织相容性复合体（MHC）I类分子组装过程中，会与内质网驻留伴侣钙连蛋白和钙网蛋白、ERp57氧化还原酶形成短暂关联，还会与塔帕辛形成短暂关联，后者介导I类分子与抗原加工相关转运体（TAP）的结合。我们在此报告从DA（RT1av1）文库中分离出编码大鼠塔帕辛的cDNA。该cDNA编码一个富含脯氨酸（11.3%）的464个残基的多肽，在其COOH末端有一个潜在的内质网滞留KK基序，预测分子量为48 kDa。对源自TAP相关蛋白凝胶内胰蛋白酶消化的肽段进行基质辅助激光解吸电离（MALDI）质谱分析，与预测翻译产物的区域匹配。在通过二维凝胶电泳分析的大鼠TAP复合物的放射性标记免疫沉淀物中，也鉴定出了具有正确分子量和预测pI的一种物质。这证实大鼠塔帕辛是大鼠MHC I类组装复合物的一个组成部分。
