Sorting signals in the MHC class II invariant chain cytoplasmic tail and transmembrane region determine trafficking to an endocytic processing compartment.
Sorting signals in the MHC class II invariant chain cytoplasmic tail and transmembrane region determine trafficking to an endocytic processing compartment.
复制标题
在MHC II类不变链细胞质尾部和跨膜区域中分类信号决定了运输到内吞处理室的。
DOI：
10.1083/jcb.126.2.317
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发表时间：
1994-07
影响因子：
7.8
通讯作者：
Collawn, J F
中科院分区：
文献类型：
--
作者：
Odorizzi, C G;Trowbridge, I S;Xue, L;Hopkins, C R;Davis, C D;Collawn, J F
MHC II类分子的靶向是由不变链(II)决定的，在那里它们遇到处理的抗原的胞内室。通过对II-转铁蛋白受体嵌合体转运的分析，我们已经在II细胞质尾部和跨膜区确定了介导这一过程的分选信号。在II胞质尾部发现了两个非酪氨酸的分选信号，它们介导了胞膜蛋白包裹的凹坑的定位，并促进了快速内吞作用。Leu7和Ile8是细胞膜最远端信号活动所必需的，而Pro15、Met16、Leu17对于膜-近端信号是重要的。相同或重叠的非基于酪氨酸的分选信号对于将II-tR嵌合体通过细胞内途径或通过质膜传递到内细胞室是必不可少的，在那里它们被迅速降解。II跨膜区也是有效地运送到内吞加工室所必需的，并且包含与II细胞质尾部不同的信号。超过80%的包含II胞浆尾部和跨膜区的II-TR嵌合体通过细胞内途径直接传递到内胞途径，这意味着II分选信号可以被位于反高尔基体中的分选机械有效地识别。
Targeting of MHC class II molecules to the endocytic compartment where they encounter processed antigen is determined by the invariant chain (Ii). By analysis of Ii-transferrin receptor (TR) chimera trafficking, we have identified sorting signals in the Ii cytoplasmic tail and transmembrane region that mediate this process. Two non-tyrosine-based sorting signals in the Ii cytoplasmic tail were identified that mediate localization to plasma membrane clathrin-coated pits and promote rapid endocytosis. Leu7 and Ile8 were required for the activity of the signal most distal to the cell membrane whereas Pro15 Met16 Leu17 were important for the membrane-proximal signal. The same or overlapping non- tyrosine-based sorting signals are essential for delivery of Ii-TR chimeras, either by an intracellular route or via the plasma membrane, to an endocytic compartment where they are rapidly degraded. The Ii transmembrane region is also required for efficient delivery to this endocytic processing compartment and contains a signal distinct from the Ii cytoplasmic tail. More than 80% of the Ii-TR chimera containing the Ii cytoplasmic tail and transmembrane region is delivered directly to the endocytic pathway by an intracellular route, implying that the Ii sorting signals are efficiently recognized by sorting machinery located in the trans-Golgi.