An isoform of the Golgi t-SNARE, syntaxin 5, with an endoplasmic reticulum retrieval signal
An isoform of the Golgi t-SNARE, syntaxin 5, with an endoplasmic reticulum retrieval signal
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DOI：
10.1091/mbc.8.9.1777
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发表时间：
1997-09-01
影响因子：
3.3
通讯作者：
Warren, G
中科院分区：
文献类型：
--
作者：
Hui, N;Nakamura, N;Warren, G
早期高尔基体 t-SNARE（靶膜相关可溶性 N-乙基马来酰亚胺敏感因子附着蛋白受体）突触蛋白 5 被认为指定了源自内质网 (ER) 的 COPI 和 COPII 包被囊泡以及逆行途径上的 COPI 囊泡的对接位点。我们现在表明，有两种形式的突触融合蛋白 5 似乎是通过不同的翻译起始从相同的 mRNA 生成的。简短形式 (35 kDa) 对应于已发布的序列。长形式 (42 kDa) 具有 N 末端细胞质延伸，其中包含预测的 II 型 ER 修复信号。当移植到报告分子上时，该信号将构建体定位到内质网。生化分级分离和免疫荧光显微镜显示，高尔基体中的长形结构较少，而周围的点状结构较多，其中一些与中间室的标记物共定位。预计芽殖酵母中不存在长形式，这表明其具有高等生物特有的功能。
The early Golgi t-SNARE (target-membrane-associated soluble-N-ethylmaleimide-sensitive factor attachment protein receptor) syntaxin 5 is thought to specify the docking site for both COPI and COPII coated vesicles originating from the endoplasmic reticulum (ER) and COPI vesicles on the retrograde pathway. We now show that there are two forms of syntaxin 5 that appear to be generated from the same mRNA by alternative initiation of translation. The short form (35 kDa) corresponds to the published sequence. The long form (42 kDa) has an N-terminal cytoplasmic extension containing a predicted type II ER retrieval signal. When grafted onto a reporter molecule, this signal localized the construct to the ER. Biochemical fractionation and immunofluorescence microscopy showed that there was less of the long form in the Golgi apparatus and more in peripheral punctate structures, some of which colocalized with markers of the intermediate compartment. The predicted absence of the long form in budding yeast points to a function unique to higher organisms.