Tapasin-related protein TAPBPR is an additional component of the MHC class I presentation pathway
Tapasin-related protein TAPBPR is an additional component of the MHC class I presentation pathway
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DOI：
10.1073/pnas.1222342110
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发表时间：
2013-02-26
影响因子：
11.1
通讯作者：
Trowsdale, John
中科院分区：
文献类型：
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作者：
Boyle, Louise H.;Hermann, Clemens;Trowsdale, John
Tapasin是肽加载复合物（PLC）的组成部分，对于有效地将肽加载到MHC I类分子上是重要的。我们研究了Tapasin相关蛋白TAPBPR的功能。与Tapasin一样，TAPBPR广泛表达，可由IFN-γ诱导，并与MHC类结合！与内质网中的β 2-微球蛋白偶联。与Tapasin相反，TAPBPR不结合ERp 57或钙网蛋白，并且不是PLC的组成部分。β 2-微球蛋白对于TAPBPR和MHC I类之间的关联是必需的。然而，TAPBPR和MHC I类之间的关联在没有功能PLC的情况下发生，这表明不需要肽。TAPBPR的表达通过分泌途径降低了MHC I类分子的成熟速率，并阻断了MHC I类分子与PLC的结合。TAPBPR：MHC I类复合体通过高尔基体，证明了TAPBPR超越内质网/顺式高尔基体的功能。TAPBPR作为MHC I类抗原呈递途径的额外组分的鉴定表明，控制MHC I类表达的机制仍不完全清楚。
Tapasin is an integral component of the peptide-loading complex (PLC) important for efficient peptide loading onto MHC class I molecules. We investigated the function of the tapasin-related protein, TAPBPR. Like tapasin, TAPBPR is widely expressed, IFN-gamma-inducible, and binds to MHC class! coupled with beta 2-microglobulin in the endoplasmic reticulum. In contrast to tapasin, TAPBPR does not bind ERp57 or calreticulin and is not an integral component of the PLC. beta 2-microglobulin is essential for the association between TAPBPR and MHC class I. However, the association between TAPBPR and MHC class I occurs in the absence of a functional PLC, suggesting peptide is not required. Expression of TAPBPR decreases the rate of MHC class I maturation through the secretory pathway and prolongs the association of MHC class Ion the PLC. The TAPBPR: MHC class I complex trafficks through the Golgi apparatus, demonstrating a function of TAPBPR beyond the endoplasmic reticulum/cis-Golgi. The identification of TAPBPR as an additional component of the MHC class I antigen-presentation pathway demonstrates that mechanisms controlling MHC class I expression remain incompletely understood.