GOLGI TRANSPORT 1B Regulates Protein Export from the Endoplasmic Reticulum in Rice Endosperm Cells
GOLGI TRANSPORT 1B Regulates Protein Export from the Endoplasmic Reticulum in Rice Endosperm Cells
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高尔基转运 1B 调节水稻胚乳细胞内质网的蛋白质输出。
DOI：
10.1105/tpc.16.00717
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发表时间：
2016-11-01
期刊：
影响因子：
11.6
通讯作者：
Wan, Jianmin
中科院分区：
文献类型：
--
作者：
Wang, Yihua;Liu, Feng;Wan, Jianmin
在真核生物中，外壳蛋白复合物II（COPII）介导新合成的蛋白质从内质网（ER）向其他内膜隔室顺行运输的第一步。一组进化上保守的蛋白质（Sar 1，Sec 23，Sec 24，Sec 13和Sec 31）构成了基本的COPII外壳机器;然而，COPII外壳组装如何调节的细节仍然不清楚。在这里，我们报告了一个蛋白质转运突变体水稻（Oryza sativa），命名为谷蛋白前体积累4（gpa 4），积累57 kD谷蛋白前体，并形成两种类型的ER衍生的异常结构。GPA 4编码进化上保守的膜蛋白GOT 1B（也称为GLUP 2），与酿酒酵母GOT 1 p同源。水稻GOT 1B蛋白与拟南芥Sar 1b共定位在高尔基体相关的内质网出口位点（ERES）时，他们在烟草本塞曼共表达。此外，GOT 1B与水稻Sec 23物理相互作用，并且这两种蛋白质与水稻Sar 1b存在于相同的复合物中。gpa 4突变体中水稻Sar 1在内膜系统中的分布、与水稻Sec 23 c的结合以及ERES组织模式发生了显着改变。两者合计，我们的研究结果表明，GOT 1B在介导COPII囊泡形成ERES中起着重要的作用，从而促进植物细胞中分泌蛋白的顺行运输。
Coat protein complex II (COPII) mediates the first step of anterograde transport of newly synthesized proteins from the endoplasmic reticulum (ER) to other endomembrane compartments in eukaryotes. A group of evolutionarily conserved proteins (Sar1, Sec23, Sec24, Sec13, and Sec31) constitutes the basic COPII coat machinery; however, the details of how the COPII coat assembly is regulated remain unclear. Here, we report a protein transport mutant of rice (Oryza sativa), named glutelin precursor accumulation4 (gpa4), which accumulates 57-kD glutelin precursors and forms two types of ER-derived abnormal structures. GPA4 encodes the evolutionarily conserved membrane protein GOT1B (also known as GLUP2), homologous to the Saccharomyces cerevisiae GOT1p. The rice GOT1B protein colocalizes with Arabidopsis thaliana Sar1b at Golgi-associated ER exit sites (ERESs) when they are coexpressed in Nicotiana benthamiana. Moreover, GOT1B physically interacts with rice Sec23, and both proteins are present in the same complex(es) with rice Sar1b. The distribution of rice Sar1 in the endomembrane system, its association with rice Sec23c, and the ERES organization pattern are significantly altered in the gpa4 mutant. Taken together, our results suggest that GOT1B plays an important role in mediating COPII vesicle formation at ERESs, thus facilitating anterograde transport of secretory proteins in plant cells.