人类抗原加工相关转运体结构和功能的研究进展

Recent advances on the structure and function of the transporter associated with antigen processing

在人类获得性免疫中，为了有效的激活细胞毒T淋巴细胞，MHC-Ⅰ抗原肽复合体在细胞表面的表达甚为关健。这一过程涉及到多种蛋白的共同参与，如MHC-Ⅰ、抗原加工相关转运体（TAP）、蛋白酶体和各种分子伴侣如Tapasin，ERp57，钙网蛋白等等。而负责运输抗原肽，并把它负载到MHC-Ⅰ分子上的是TAP，这一步受阻，将导致细胞表面MHC-Ⅰ类分子的低表达或不表达，严重影响免疫监视。

It is pivotal to express of the MHC- Ⅰ -peptide complexes on the cell surface for effective activating cytotoxic T lymphocytes （CTLs） in the process of adaptive immune response. There are several components working together during this process including major histocompatibility complex class Ⅰ molecules （MHC- Ⅰ ）, the transporter associated with antigen processing （TAP）, proteasome, ERp57, tapasin and calreticulin, etc. The most important component is TAP by which antigen peptides are translocated into endoplasmic reticulum （ER） lumen from cytosol and then loaded onto MHC- Ⅰ . If this step was obstructed, it would cause MHC-Ⅰ- peptide deficiency and failed immune surveillance. The structure and function of TAP and the relationship between TAP and diseases are reviewed here.