The Saccharomyces cerevisiae protein Mnn10p/Bed1p is a subunit of a Golgi mannosyltransferase complex
The Saccharomyces cerevisiae protein Mnn10p/Bed1p is a subunit of a Golgi mannosyltransferase complex
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DOI：
10.1074/jbc.274.10.6579
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发表时间：
1999-03-05
影响因子：
4.8
通讯作者：
Munro, S
中科院分区：
文献类型：
--
作者：
Jungmann, J;Rayner, JC;Munro, S
在酵母酿酒酵母中，细胞壁和周质蛋白上的许多N-连接聚糖通过添加甘露聚糖（一种含有大量甘露糖的多糖）而被修饰。甘露聚糖包含约50个α-1，6-连接的甘露糖的主链，其上连接有许多由α-1，2-连接和α-1，3-连接的甘露糖组成的支链。甘露聚糖主链的起始和随后的延伸由顺式高尔基体中的两种蛋白质复合物进行。在这项研究中，我们表明MNN 10/BED 1基因的产物是这些复合物之一的组成部分，该复合物延长了骨架。对该复合物中蛋白质之间相互作用的分析表明，Mnn 10 p和四种先前表征的蛋白质（Anp 1 p、Mnn 9 p、Mnn 11 p和Hoc 1 p）实际上都是相同大结构的组分，缺失Mnn 10 p或其同源物Mnn 11 p，导致体内甘露聚糖合成缺陷，对从突变菌株分离的复合物的酶活性的分析表明，Mnn 10 p和Mnn 11 p负责该复合物的大部分α-1，6-聚合活性。
In the yeast Saccharomyces cerevisiae many of the N-linked glycans on cell wall and periplasmic proteins are modified by the addition of mannan, a large mannose-containing polysaccharide. Mannan comprises a backbone of approximately 50 alpha-1,6-linked mannoses to which are attached many branches consisting of alpha-1,2-linked and alpha-1,3-linked mannoses. The initiation and subsequent elongation of the mannan backbone is performed by two complexes of proteins in the cis Golgis. In this study we show that the product of the MNN10/BED1 gene is a component of one of these complexes, that which elongates the backbone. Analysis of interactions between the proteins in this complex shows that Mnn10p, and four previously characterized proteins (Anp1p, Mnn9p, Mnn11p, and Hoc1p) are indeed all components of the same large structure, Deletion of either Mnn10p, or its homologue Mnn11p, results in defects in mannan synthesis in vivo, and analysis of the enzymatic activity of the complexes isolated from mutant strains suggests that Mnn10p and Mnn11p are responsible for the majority of the alpha-1,6-polymerizing activity of the complex.