Localization of TGN38 to the trans-Golgi network: involvement of a cytoplasmic tyrosine-containing sequence.
Localization of TGN38 to the trans-Golgi network: involvement of a cytoplasmic tyrosine-containing sequence.
复制标题
DOI：
10.1083/jcb.120.5.1123
复制
发表时间：
1993-03
期刊：
影响因子：
--
通讯作者：
Bonifacino JS
中科院分区：
文献类型：
--
作者：
Humphrey JS;Peters PJ;Yuan LC;Bonifacino JS
通过检查嵌合蛋白的亚细胞分布来研究蛋白定位于TGN，其中TGN蛋白TGN 38的胞质和/或跨膜结构域被质膜蛋白Tac的类似结构域取代。使用免疫荧光和免疫电子显微镜，发现TGN 38的COOH末端胞质结构域足以将嵌合蛋白定位于TGN。缺失分析确定了一个包含关键序列YQRL的11个氨基酸的片段，足以用于TGN定位。TGN本地化被废除的突变的酪氨酸或亮氨酸残基在这个序列中的丙氨酸，或精氨酸残基的天冬氨酸。除了指定TGN定位外，11个氨基酸的片段作为内化信号是有活性的，尽管单独内化的性质不足以赋予TGN定位。过表达的嵌合蛋白含有TGN定位决定簇导致其检测在质膜和细胞内囊泡，并取消检测内源性TGN 38。这些结果表明，离散的细胞质决定簇可以介导蛋白质定位到TGN，并揭示了一个新的作用，酪氨酸基序在这个过程中。
Protein localization to the TGN was investigated by examining the subcellular distribution of chimeric proteins in which the cytoplasmic and/or transmembrane domains of the TGN protein, TGN38, were substituted for the analogous domains of the plasma membrane protein, Tac. Using immunofluorescence and immunoelectron microscopy, the COOH- terminal cytoplasmic domain of TGN38 was found to be sufficient for localization of the chimeric proteins to the TGN. Deletion analysis identified an 11-amino acid segment containing the critical sequence, YQRL, as being sufficient for TGN localization. TGN localization was abrogated by mutation of the tyrosine or leucine residues in this sequence to alanine, or of the arginine residue to aspartate. In addition to specifying TGN localization, the 11-amino acid segment was active as an internalization signal, although the property of internalization alone was insufficient to confer TGN localization. Overexpression of chimeric proteins containing TGN localization determinants resulted in their detection at the plasma membrane and in intracellular vesicles, and abolished detection of endogenous TGN38. These results suggest that discrete cytoplasmic determinants can mediate protein localization to the TGN, and reveal a novel role for tyrosine-based motifs in this process.