Peptide-receptive major histocompatibility complex class I molecules cycle between endoplasmic reticulum and cis-golgi in wild-type lymphocytes
Peptide-receptive major histocompatibility complex class I molecules cycle between endoplasmic reticulum and cis-golgi in wild-type lymphocytes
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DOI：
10.1074/jbc.m701721200
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发表时间：
2007-10-19
影响因子：
4.8
通讯作者：
Springer, Sebastian
中科院分区：
文献类型：
--
作者：
Garstka, Malgorzata;Borchert, Britta;Springer, Sebastian
在与高亲和力肽结合并将其转运至细胞表面之前，主要组织相容性复合物 I 类分子通过保留在内质网 (ER) 中、通过 ER-高尔基体中间室和/或顺式高尔基体再循环而保留在细胞内。使用荧光显微镜和新型体外 COPII（ER 至 ER-高尔基中间室）囊泡形成测定，我们发现在缺乏与抗原呈递相关的功能转运蛋白的淋巴细胞和成纤维细胞中，I 类分子离开 ER 并到达顺式高尔基体。有趣的是，在野生型 T1 淋巴瘤细胞中，肽占据和肽接受的 I 类分子同时从 ER 膜输出，效率相似。我们的结果表明，高亲和力肽的结合和从 ER 的退出并不耦合，主要组织相容性复合物 I 类质量控制区室在标准条件下延伸到高尔基体中，并且肽加载到 I 类分子上可能发生在 ER 后区室中。
Prior to binding to a high affinity peptide and transporting it to the cell surface, major histocompatibility complex class I molecules are retained inside the cell by retention in the endoplasmic reticulum ( ER), recycling through the ER-Golgi intermediate compartment and possibly the cis-Golgi, or both. Using fluorescence microscopy and a novel in vitro COPII ( ER-to-ER-Golgi intermediate compartment) vesicle formation assay, we find that in both lymphocytes and fibroblasts that lack the functional transporter associated with antigen presentation, class I molecules exit the ER and reach the cis-Golgi. Intriguingly, in wild-type T1 lymphoma cells, peptide-occupied and peptide-receptive class I molecules are simultaneously exported from ER membranes with similar efficiencies. Our results suggest that binding of high affinity peptide and exit from the ER are not coupled, that the major histocompatibility complex class I quality control compartment extends into the Golgi apparatus under standard conditions, and that peptide loading onto class I molecules may occur in post-ER compartments.