Localization of GDP-mannose transporter in the Golgi requires retrieval to the endoplasmic reticulum depending on its cytoplasmic tail and coatomer
Localization of GDP-mannose transporter in the Golgi requires retrieval to the endoplasmic reticulum depending on its cytoplasmic tail and coatomer
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DOI：
10.1242/jcs.01491
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发表时间：
2004-11-01
影响因子：
4
通讯作者：
Yoda, K
中科院分区：
文献类型：
--
作者：
Abe, M;Noda, Y;Yoda, K
酿酒酵母（Saccharomyces cerevisiae） gdp -甘露糖转运蛋白（GMT）是高尔基体中核苷酸-糖转运蛋白家族的一员，由必需基因VRG4/VIG4编码。我们在分泌突变细胞中检测了GMT，以研究其在高尔基体中的定位机制。在非允许温度下，大多数GMT出现在具有缺陷COPII的sec23（ts）细胞的内质网和具有缺陷COPI的sec21（ts）细胞的液泡中。暴露于细胞质的GMT的c端亲水性肽与COPI外壳的一个亚基Ret2p结合。在跨膜结构域附近失去一簇赖氨酸的突变肽衍生物与Ret2p的结合活性降低，具有该序列的GMT被传递到液泡中。我们的研究结果表明，GMT通过再循环到内质网而从液泡中逃逸，而回收需要富含赖氨酸的c端尾部，该末端尾部可以结合到COPI外壳上。
The Saccharomyces cerevisiae GDP-mannose transporter (GMT) encoded by the essential gene VRG4/VIG4 is a member of the nucleotide-sugar transporter family in the Golgi apparatus. We examined GMT in the secretory mutant cells to investigate the mechanism of its localization in the Golgi. At the nonpermissive temperature, most GMT was found in the endoplasmic reticulum of sec23(ts) cells, which have defective COPII, and in the vacuole of sec21(ts) cells, which have defective COPI. The C-terminal hydrophilic peptide of GMT that is exposed to the cytosol binds to Ret2p, a subunit of the COPI coat. Mutant peptide derivatives that have lost a cluster of lysine in the vicinity of the transmembrane domain had reduced binding activity to Ret2p and the GMT with this sequence was delivered to the vacuole. Our results indicate that GMT escapes from delivery to the vacuole by recycling to the endoplasmic reticulum and retrieval requires the lysine-rich C-terminal tail that can bind to the COPI coat.