CELL-SURFACE HLA-DR INVARIANT CHAIN COMPLEXES ARE TARGETED TO ENDOSOMES BY RAPID INTERNALIZATION
CELL-SURFACE HLA-DR INVARIANT CHAIN COMPLEXES ARE TARGETED TO ENDOSOMES BY RAPID INTERNALIZATION
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DOI：
10.1073/pnas.90.18.8581
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发表时间：
1993-09-15
影响因子：
11.1
通讯作者：
LONG, EO
中科院分区：
文献类型：
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作者：
ROCHE, PA;TELETSKI, CL;LONG, EO
主要组织相容性复合体（MHC）的II类分子结合来自递送到内吞隔室中的蛋白质抗原的肽，并将这些肽呈递给CD 4 + T细胞。负载肽的功能性MHC II类分子的前体是与II类α异二聚体相关的不变链的复合物。新合成的MHC II类分子靶向内体是由不变链介导的，但胞内转运途径尚不清楚。这项研究表明，在人类B细胞系中，大量的MHC II类不变链复合物通过从细胞表面快速内化而到达内体。细胞表面MHC II类不变链复合物及其表面半衰期的定量显示，每分钟有3000个复合物内化到内体中。这种高效的内吞作用是由不变链的胞质尾介导的。内化后，不变链从MHC II类-不变链复合物中解离。这一途径可能代表了一个重要的机制，加载II类分子与免疫原性肽从几个内吞隔室。
Class II molecules of the major histocompatibility complex (MHC) bind peptides derived from protein antigens delivered into endocytic compartments and present these peptides to CD4+ T cells. The precursors to functional MHC class II molecules loaded with peptides are complexes of the invariant chain associated with class II alphabeta heterodimers. Targeting of newly synthesized MHC class II molecules to endosomes is mediated by the invariant chain, but the intracellular transport route is not known. This study demonstrates that in a human B-cell line a large population of MHC class II-invariant chain complexes reaches endosomes by rapid internalization from the cell surface. Quantitation of cell surface MHC class II-invariant chain complexes and of their surface half-life revealed that 3000 complexes internalized per minute into endosomes. This highly efficient endocytosis was mediated by the cytoplasmic tail of the invariant chain. After internalization, the invariant chain dissociated from the MHC class II-invariant chain complexes. This pathway may represent an important mechanism for loading class II molecules with immunogenic peptides from several endocytic compartments.