Evidence that the entire Golgi apparatus cycles in interphase HeLa cells: sensitivity of Golgi matrix proteins to an ER exit block
Evidence that the entire Golgi apparatus cycles in interphase HeLa cells: sensitivity of Golgi matrix proteins to an ER exit block
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DOI：
10.1083/jcb.200103104
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发表时间：
2001-11-12
影响因子：
7.8
通讯作者：
Storrie, B
中科院分区：
文献类型：
--
作者：
Miles, S;McManus, H;Storrie, B
我们通过评估12种不同的高尔基区蛋白对内质网出口阻断的反应来测试整个高尔基体在哺乳动物间期细胞中是否是一个动态结构。所选择的蛋白质跨越了高尔基体，包括高尔基糖基转移酶和假定的基质蛋白。在蛋白质合成抑制剂存在的情况下，通过显微注射gtp限制性Sar1p突变蛋白或通过质粒编码表达相同的显性阴性Sar1p来阻断内质网的蛋白质输出。所有高尔基区蛋白在内质网出口阻断的情况下，通过常规和共聚焦荧光显微镜对丢失的核旁高尔基体样分布进行了检测，尽管对Sar1p浓度有不同的依赖性。Ga1NAcT2的重分布对低Sar1p（dn）浓度比巨肽或GM130更敏感。p27、COPI和p115的再分配速度最快。Giantin， GM130和GaINAcT2以近似相等的动力学重新定位。所有的整体膜蛋白都有明显的内质网积累。er积累的高尔基区蛋白是功能性的。光漂白实验表明，高尔基到内质网蛋白循环发生在没有任何内质网出口阻断的情况下。我们得出结论，整个高尔基体是一个动态结构，并表明大多数（如果不是全部的话）高尔基区域积分膜蛋白在间期细胞中通过内质网循环。
We tested whether the entire Golgi apparatus is a dynamic structure in interphase mammalian cells by assessing the response of 12 different Golgi region proteins to an endoplasmic reticulum (ER) exit block. The proteins chosen spanned the Golgi apparatus and included both Golgi glycosyltransferases and putative matrix proteins. Protein exit from ER was blocked either by microinjection of a GTP-restricted Sar1p mutant protein in the presence of a protein synthesis inhibitor, or by plasmid-encoded expression of the same dominant negative Sar1p. All Golgi region proteins examined lost juxtanuclear Golgi apparatus-like distribution as scored by conventional and confocal fluorescence microscopy in response to an ER exit block, albeit with a differential dependence on Sar1p concentration. Redistribution of Ga1NAcT2 was more sensitive to low Sar1p(dn) concentrations than giantin or GM130. Redistribution was most rapid for p27, COPI, and p115. Giantin, GM130, and GaINAcT2 relocated with approximately equal kinetics. Distinct ER accumulation could be demonstrated for all integral membrane proteins. ER-accumulated Golgi region proteins were functional. Photobleaching experiments indicated that Golgi-to-ER protein cycling occurred in the absence of any ER exit block. We conclude that the entire Golgi apparatus is a dynamic structure and suggest that most, if not all, Golgi region-integral membrane proteins cycle through ER in interphase cells.