ARF is required for maintenance of yeast Golgi and endosome structure and function
ARF is required for maintenance of yeast Golgi and endosome structure and function
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DOI：
10.1091/mbc.9.3.653
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发表时间：
1998-03-01
影响因子：
3.3
通讯作者：
Graham, TR
中科院分区：
文献类型：
--
作者：
Gaynor, EC;Chen, CY;Graham, TR
ADP核糖基化因子（ARF）被认为在高尔基体膜募集外被体（COPI）以驱动运输囊泡出芽中起关键作用。携带突变COPI蛋白的酵母菌株表现出逆行高尔基体到内质网蛋白运输的缺陷和顺行内质网到高尔基体蛋白运输的显著货物选择性缺陷。为了确定arf突变体是否表现出相似的表型，在arf突变细胞中检查了多种货物蛋白的顺行运输动力学，令人惊讶的是，COPI依赖性和COPI非依赖性货物蛋白都表现出相当的缺陷。逆行二赖氨酸介导的运输似乎也是低效的arf突变体，和coatomer突变体没有检测到的顺行运输缺陷表现出合成的生长缺陷时，结合arf 1三角洲，支持ARF在逆行运输中的作用。值得注意的是，我们发现，早期和中期高尔基体糖基转移酶定位于异常大的环形结构。内吞标记FM 4 -64也染色类似，但一般较大的环形结构的路线从质膜的空泡在arf突变体。布雷菲德菌素A类似地扰乱内体形态，并且还抑制FM 4 -64从内体结构到液泡的运输。arf突变体细胞的电子显微镜显示了似乎是相互连接的膜小管的空心球的存在，这可能对应于荧光环结构。总之，这些观察结果表明，细胞器的形态是显着影响比运输的ARF突变体，这表明ARF在调节膜动力学的基本作用。产生这种戏剧性的细胞内细胞器的形态变化和它的关系ARF在外套组装功能的可能机制进行了讨论。
ADP ribosylation factor (ARF) is thought to play a critical role in recruiting coatomer (COPI) to Golgi membranes to drive transport vesicle budding. Yeast strains harboring mutant COPI proteins exhibit defects in retrograde Golgi to endoplasmic reticulum protein transport and striking cargo-selective defects in anterograde endoplasmic reticulum to Golgi protein transport. To determine whether arf mutants exhibit similar phenotypes, the anterograde transport kinetics of multiple cargo proteins were examined in arf mutant cells, and, surprisingly, both COPI-dependent and COPI-independent cargo proteins exhibited comparable defects. Retrograde dilysine-mediated transport also appeared to be inefficient in the arf mutants, and coatomer mutants with no detectable anterograde transport defect exhibited a synthetic growth defect when combined with arf1 Delta, supporting a role for ARF in retrograde transport. Remarkably, we found that early and medial Golgi glycosyltransferases localized to abnormally large ring-shaped structures. The endocytic marker FM4-64 also stained similar, but generally larger ring-shaped structures en route from the plasma membrane to the vacuole in arf mutants. Brefeldin A similarly perturbed endosome morphology and also inhibited transport of FM4-64 from endosomal structures to the vacuole. Electron microscopy of arf mutant cells revealed the presence of what appear to be hollow spheres of interconnected membrane tubules which likely correspond to the fluorescent ring structures. Together, these observations indicate that organelle morphology is significantly more affected than transport in the arf mutants, suggesting a fundamental role for ARF in regulating membrane dynamics. Possible mechanisms for producing this dramatic morphological change in intracellular organelles and its relation to the function of ARF in coat assembly are discussed.