ORGANELLAR PROTEOMICS REVEALS GOLGI ARGININE DIMETHYLATION

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。高尔基复合体的功能是对新合成的蛋白质和脂类进行翻译后修饰，并将它们分类到各自的功能部位。在本研究中，通过经典的细胞分离方法分离了堆积的高尔基体组分，并利用多维蛋白质鉴定技术对其蛋白质补体(高尔基体蛋白质组)进行了鉴定。许多已鉴定的蛋白质是已知的高尔基体居民，而预测的这些蛋白质中有%是跨膜蛋白。定位于其他细胞器的蛋白质也被鉴定出来，加强了高尔基体与内质网和细胞骨架之间功能接口的报道。重要的是，共鉴定出41个功能未知的蛋白质。选择其中两个进行进一步分析，证实了高尔基体的定位。其中一个可能的甲基转移酶是精氨酸二甲基化，进一步的蛋白质组学分析表明，高尔基体蛋白质组中共有18个蛋白质发生精氨酸二甲基化。这项调查说明了蛋白质组学在发现新的细胞器功能方面的应用，并导致1)丰富的高尔基组分的蛋白质图谱；2)鉴定了41个以前未鉴定的蛋白质，其中两个已确认为高尔基体定位；3)鉴定了高尔基体蛋白质中的精氨酸二甲基化残基；以及4)证实了高尔基体组分中的甲基转移酶活性。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The Golgi complex functions to posttranslationally modify newly synthesized proteins and lipids and to sort them to their sites of function. In this study, a stacked Golgi fraction was isolated by classical cell fractionation, and the protein complement (the Golgi proteome) was characterized using multidimensional protein identification technology. Many of the proteins identified are known residents of the Golgi, and 64% of these are predicted transmembrane proteins. Proteins localized to other organelles also were identified, strengthening reports of functional interfacing between the Golgi and the endoplasmic reticulum and cytoskeleton. Importantly, 41 proteins of unknown function were identified. Two were selected for further analysis, and Golgi localization was confirmed. One of these, a putative methyltransferase, was shown to be arginine dimethylated, and upon further proteomic analysis, arginine dimethylation was identified on 18 total proteins in the Golgi proteome. This survey illustrates the utility of proteomics in the discovery of novel organellar functions and resulted in 1) a protein profile of an enriched Golgi fraction; 2) identification of 41 previously uncharacterized proteins, two with confirmed Golgi localization; 3) the identification of arginine dimethylated residues in Golgi proteins; and 4) a confirmation of methyltransferase activity within the Golgi fraction.