GMx33:: A novel family of trans-Golgi proteins identified by proteomics
GMx33:: A novel family of trans-Golgi proteins identified by proteomics
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DOI：
10.1034/j.1600-0854.2000.011206.x
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发表时间：
2000-12-01
期刊：
影响因子：
4.5
通讯作者：
Howell, KE
中科院分区：
文献类型：
--
作者：
Wu, CC;Taylor, RS;Howell, KE
高尔基复合体的已知功能包括分泌蛋白、膜蛋白和脂质的分类、包装、翻译后修饰和运输。其他功能对细胞生物学家来说仍然难以捉摸。为了鉴定新的高尔基体蛋白，我们开展了一个蛋白质组学项目，利用二维高尔基体绘制细胞器的主要蛋白质图谱，利用串联质谱法鉴定未知蛋白，并利用 GFP 融合结构筛选高尔基体居民。鉴定了多个未知物，并在此报告了其中一种蛋白质的初步表征。 GMx33 α 是胞质高尔基体相关蛋白保守家族的成员，与任何已知的功能域或蛋白没有同源性。生化分析表明，GMx33 α 差异性地分配到多种去污剂提取的所有相中，二维免疫印迹显示，存在与高尔基体相关的 GMx33 α 的多种差异修饰形式，其中一些被磷酸化。有证据表明这些翻译后修饰调节其与高尔基体的关联。在高尔基体芽泡上未发现 GMx33 α，免疫电子显微镜将 GMx33 α 共定位于与正常大鼠肾细胞中的 TGN38 相同的三个池的反面。这项工作代表了一个新的反式高尔基体相关蛋白家族的初步表征。
The known functions of the Golgi complex include the sorting, packaging, post-translational modification, and transport of secretory proteins, membrane proteins, and lipids. Other functions still remain elusive to cell biologists. With the goal of identifying novel Golgi proteins, a proteomics project was undertaken to map the major proteins of the organelle using two-dimensional golgis, to identify the unknowns using tandem mass spectrometry, and to screen for Golgi residents using GFP-fusion constructs. Multiple unknowns were identified, and the initial characterization of one of these proteins is reported here. GMx33 alpha is a member of a conserved family of cytosolic Golgi-associated proteins with no known homology to any known functional domain or protein. Biochemical analyses show that GMx33 alpha differentially partitions into all phases of multiple detergent extractions, and two-dimensional immunoblots reveal that there are multiple differentially modified forms of GMx33 alpha associated with the Golgi, several of which are phosphorylated. Evidence suggests that these post-translational modifications regulate its association with the Golgi. GMx33 alpha was not found on Golgi budded vesicles, and immune-electron microscopy co-localizes GMx33 alpha to the trans-face on the same three cisternae as TGN38 in normal rat kidney cells. This work represents the preliminary characterization of a novel family of trans-Golgi-associated proteins.