The transmembrane domain of a carboxyl-terminal anchored protein determines localization to the endoplasmic reticulum
The transmembrane domain of a carboxyl-terminal anchored protein determines localization to the endoplasmic reticulum
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DOI：
10.1074/jbc.272.3.1970
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发表时间：
1997-01-17
影响因子：
4.8
通讯作者：
Weissman, AM
中科院分区：
文献类型：
--
作者：
Yang, M;Ellenberg, J;Weissman, AM
UBC6是一种C-末端膜锚定(IV型)蛋白，产于酿酒酵母体内，存在于内质网中。当在哺乳动物细胞中表达时，这种新的泛素结合酶也定位于内质网。UBC6缺乏管腔结构域，并且不包含已知的内质网滞留信号。对UBC的胞液结构域与异源跨膜结构域相连或UBC6跨膜结构域与无关的可溶性蛋白相连的嵌合蛋白的分析表明，UBC6的跨膜结构域在其间隔定位中起主导作用。通过将野生型UBC6疏水片段从17个氨基酸延长到21个氨基酸，从而重新靶向高尔基复合体，评估了跨膜区介导的UBC6亚细胞靶向的基础。长度进一步增加到26个氨基酸后，这种修饰的蛋白质就可以穿过分泌途径，在质膜上获得表达。这些发现与模型一致，在没有主要的胞浆或管腔靶向决定因素的情况下，蛋白质可以根据其跨膜结构域与周围脂双层之间的相互作用在分泌途径中进行分类。
UBC6 is a C-terminal membrane-anchored (type IV) protein, native to Saccharomyces cerevisiae, where it is found in the endoplasmic reticulum. When expressed in mammalian cells, this novel ubiquitin-conjugating enzyme also localizes to the endoplasmic reticulum. UBC6 lacks a lumenal domain and contains no known endoplasmic reticulum retention signals. Analysis of chimeric proteins in which the cytosolic domain of UBC is linked to a heterologous transmembrane domain, or in which the UBC6 transmembrane domain is appended to an unrelated soluble protein, led to the determination that the transmembrane domain of UBC6 plays a dominant role in its compartmental localization. The basis for the transmembrane domain-mediated subcellular targeting of UBC6 was evaluated by lengthening the wild type UBC6 hydrophobic segment from 17 to 21 amino acids, which resulted in re-targeting to the Golgi complex. A further increase in length to 26 amino acids allowed this modified protein to traverse the secretory pathway and gain expression at the plasma membrane. These findings are consistent with models in which, in the absence of dominant cytosolic or lumenal targeting determinants, proteins may be sorted within the secretory pathway based on interactions between their trans membrane domains and the surrounding lipid bilayer.