LOCALIZATION OF COMPONENTS INVOLVED IN PROTEIN-TRANSPORT AND PROCESSING THROUGH THE YEAST GOLGI-APPARATUS
LOCALIZATION OF COMPONENTS INVOLVED IN PROTEIN-TRANSPORT AND PROCESSING THROUGH THE YEAST GOLGI-APPARATUS
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DOI：
10.1083/jcb.112.1.27
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发表时间：
1991-01-01
影响因子：
7.8
通讯作者：
SCHEKMAN, R
中科院分区：
文献类型：
--
作者：
FRANZUSOFF, A;REDDING, K;SCHEKMAN, R
酿酒酵母sec7突变体在蛋白质通过高尔基体的运输过程中表现出多效性缺陷，并在限制性生长温度(37摄氏度)下阐述了一系列高尔基体类池子。Sec7基因编码一种必需的高分子量蛋白质(227kD)，在体内被磷酸化。在细胞裂解产物中，Sec7蛋白(Sec7p)以可沉淀和可溶两种形式被回收。在SEC细胞中看到的Sec7p相关结构的点状免疫荧光图案在Sec14突变酵母中融合在一起，该突变酵母在37℃时积累了夸大的高尔基池。Sec7p可能作为一种外周膜蛋白，在可溶的胞液池和可沉积的膜相关复合体之间循环，因为它在囊泡通过高尔基体的运输中起着至关重要的作用。跨膜Kex2蛋白酶处理酵母分泌途径中分泌多肽的前体，也通过间接免疫荧光定位于酵母细胞中的多种结构(Redding，K.，和R.Fuller，提交发表的手稿)。在双重免疫荧光标记实验中，发现Sec7和Kex2蛋白有显著的共存。这两个抗原的共存，一个参与蛋白质通过高尔基体的运输，另一个参与后期高尔基体的加工，支持我们已经可视化了酵母高尔基体的结论。
Saccharomyces cerevisiae sec7 mutants exhibit pleiotropic deficiencies in the transit of proteins through the Golgi apparatus, and elaborate an array of Golgi-apparatus-like cisternae at a restrictive growth temperature (37-degrees-C). The SEC7 gene encodes an essential high-molecular weight protein (227 kD) that is phosphorylated in vivo. In cell lysates, Sec7 protein (Sec7p) is recovered in both sedimentable and soluble fractions. A punctate immunofluorescent pattern of Sec7p-associated structures seen in SEC cells coalesces in sec14 mutant yeast that accumulate exaggerated Golgi cisternae at 37-degrees-C. Sec7p may function as a peripheral membrane protein that cycles between a soluble, cytosolic pool and a sedimentable, membrane-associated complex for its essential role in vesicular traffic through the Golgi apparatus.The transmembrane Kex2 protease, which processes precursors of secreted peptides within the yeast secretory pathway, is also localized by indirect immunofluorescence to multiple structures in the yeast cell (Redding, K., and R. Fuller, manuscript submitted for publication). In double-immunofluorescence labeling experiments, significant colocalization of Sec7 and Kex2 proteins was found. Colocalization of the two antigens, one implicated in protein transport through the Golgi apparatus and the other in processing within a late Golgi compartment, supports the conclusion that we have visualized the yeast Golgi apparatus.