Murine Transporter Associated with Antigen Presentation (TAP) Preferences Influence Class I–restricted T Cell Responses
Murine Transporter Associated with Antigen Presentation (TAP) Preferences Influence Class I–restricted T Cell Responses
复制标题
与抗原呈递 (TAP) 偏好相关的鼠转运蛋白影响 I 类限制性 T 细胞反应
DOI：
--
复制
发表时间：
1997
影响因子：
15.3
通讯作者：
L. Eisenlohr
中科院分区：
文献类型：
--
作者：
A. Yellen;Carol E. Laughlin;R. M. Metrione;L. Eisenlohr
与抗原呈递相关的转运蛋白（TAP）复合物将胞质肽穿梭到胞外室，与新生的主要组织相容性复合物I类分子结合。小鼠和人类TAP的生化研究已经确定底物长度和cooh末端残基的身份是运输效率的重要决定因素。然而，这些特异性在完整细胞中的存在及其对T细胞反应的影响尚未得到证实。我们设计了一种方法来研究完整细胞中TAP介导的转运，使用T细胞活化作为读数。该方法利用一组表达含有kd限制性非特异性流感核蛋白残基147-155的肽的重组痘苗病毒。每个结构的COOH末端都附加了一个由内部苏氨酸残基组成的二肽，然后是一个不同的氨基酸。这些11-mers的合成肽版本在溶血素o渗透细胞中表现出截然不同的运输能力，这与cooh末端残基的预测影响一致。每种结构的内源性表达版本的呈现需要tap介导的运输和与vacc编码的胞外cooh末端二肽酶（血管紧张素转换酶）的协同表达，以允许最小表位的解放。因此，表位特异性ctl的识别意味着tap介导的靶细胞内完整11-mer的转运。在正常检测条件下，羧基末端残基未受影响。然而，当T细胞识别受到限制时，无论是通过阻断CD8辅助受体的相互作用，还是通过减少运输底物的合成量，cooh末端效应就会显现出来。在这种条件下，那些在生化分析中运输不良的肽被低效地呈现。因此，TAP特异性在完整细胞中起作用，似乎反映了关于cooh末端残基影响的先前定义的规则，并且可以强烈影响T细胞反应。
The transporter associated with antigen presentation (TAP) complex shuttles cytosolic peptides into the exocytic compartment for association with nascent major histocompatibility complex class I molecules. Biochemical studies of murine and human TAP have established that substrate length and COOH-terminal residue identity are strong determinants of transport efficiency. However, the existence of these specificities in the intact cell and their influences on T cell responses have not been demonstrated. We have devised a method for studying TAP- mediated transport in intact cells, using T cell activation as a readout. The approach makes use of a panel of recombinant vaccinia viruses expressing peptides containing the Kd-restricted nonamer influenza nucleoprotein residues 147–155. The COOH terminus of each construct was appended with a dipeptide composed of an internal threonine residue followed by a varying amino acid. Synthetic peptide versions of these 11-mers exhibit vastly different transport capabilities in streptolysin O–permeabilized cells, in accordance with the predicted influence of the COOH-terminal residues. Presentation of the endogenously expressed version of each construct requires TAP-mediated transport and cooexpression with a vac-encoded exocytic COOH-terminal dipeptidase, angiotensin converting enzyme, to allow liberation of the minimal epitope. Recognition by epitope-specific CTLs therefore signifies TAP-mediated transport of a complete 11-mer within the target cell. Under normal assay conditions no influences of the COOH-terminal residue were revealed. However, when T cell recognition was limited, either by blocking CD8 coreceptor interactions or by decreasing the amount of transport substrate synthesized, significant COOH-terminal effects were revealed. Under such conditions, those peptides that transported poorly in biochemical assays were less efficiently presented. Therefore, TAP specificity operates in the intact cell, appears to reflect previously defined rules with regard to the influence of the COOH-terminal residue, and can strongly influence T cell responses.
酵母甲硫氨酸氨肽酶的特异性和体内氨基末端甲硫氨酸的乙酰化。
DOI：
--
发表时间：
1990
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Moerschell,RP;Hosokawa,Y;Tsunasawa,S;Sherman,F
通讯作者：
Sherman,F