TRIM proteins and the SUMO pathway: a systematic and functional analysis

TRIM蛋白是一个具有共同基本结构的蛋白大家族，但其功能和亚细胞定位非常不同。它们含有一个被称为无名指的结构域，它具有“E3泛素连接酶”的活性，这意味着它指导被称为泛素化的蛋白质修饰过程。泛素化是一种小蛋白质泛素与其他蛋白质的连接。人们认为它们的泛素连接酶活性是TRIM蛋白功能的核心。一些TRIM蛋白本身也受到另一种称为SUMOylation的蛋白质修饰过程的影响。summoylation也包括一个小蛋白质SUMO与另一个蛋白质的连接，并发生在共识位点。SUMOylation通常调节修饰蛋白的细胞内定位、稳定性和/或功能。有趣的是，泛素化和sumo酰化是相互依赖的过程。我们实验室的工作表明，人类的一个TRIM，特别是TRIM5，拥有一个共识的sumo化位点，可以调节邻近环结构域的泛素连接酶活性。计算机搜索summoylation共识位点表明，大多数人类TRIM蛋白都含有这样的基序，这意味着summoylation在该家族蛋白的功能中起着重要而普遍的作用。***我们建议建立一个研究项目，长期目标是破译TRIM蛋白和SUMOylation之间的功能关系。我们将克隆、表达和纯化所有约80个人类TRIM蛋白，包括一些从未被研究过的蛋白。将研究它们结合SUMO和被SUMO修饰的能力。将在细胞和体外实验中测试SUMOylation，并确定SUMOylation位点。sumo化和sumo相关基序在TRIM蛋白行为中的作用将通过分析其对亚细胞定位、稳定性和E3泛素连接酶活性的影响来评估。该研究项目将首次详细描述TRIM蛋白的summoylation过程，并揭示summoylation在TRIM功能中的作用。我们的系统方法将使我们能够发现多种TRIM蛋白共同的调控途径，并表征研究较少的TRIM家族成员。除了显著推进科学知识外，该研究项目在蛋白质工程方面具有潜在的应用前景

TRIM proteins are a large family of proteins that share a common basic structure but are very diverse in their functions and subcellular localization. They harbor a domain called the RING finger which has an “E3 ubiquitin ligase” activity, meaning that it guides the protein modification process known as ubiquitination. Ubiquitination consists in the linkage of a small protein, ubiquitin, to other proteins. It is believed that their ubiquitin ligase activity is central to the function of TRIM proteins. Some TRIM proteins were found to be themselves subjected to another protein modification process known as SUMOylation. SUMOylation also consists in the linkage of a small protein, SUMO, to another protein and occurs at consensus sites. SUMOylation often modulates the intracellular localization, stability and/or function of the modified proteins. Interestingly, ubiquitination and SUMOylation are inter-dependent processes. Work in our laboratory showed that one human TRIM in particular, TRIM5, harbors a consensus SUMOylation site that modulates the ubiquitin ligase activity of the adjacent RING domain. Computer searches for SUMOylation consensus sites suggested that the majority of human TRIM proteins harbor such motifs, implying that SUMOylation plays an important and general role in the function of proteins of this family. ***We propose to establish a research program with the long-term goal of deciphering the functional relationships between TRIM proteins and SUMOylation. We will clone, express and purify all ~80 human TRIM proteins, including some that have never been studied. Their capacity to bind SUMO and to be SUMOylated will be investigated. SUMOylation will be tested in cells and using in vitro assays, and SUMOylation sites will be identified. The role of SUMOylation and SUMO-relevant motifs in the behavior of TRIM proteins will be assessed by analyzing their impact on the subcellular localization, stability and E3 ubiquitin ligase activity. This research program will yield the first detailed description of the TRIM proteins SUMOylation landscape and will uncover the role of SUMOylation in TRIM functions. Our systematic approach will allow us to uncover regulatory pathways common to multiple TRIM proteins and to characterize poorly studied members of the TRIM family. In addition to significantly advancing scientific knowledge, this research program has potential applications in protein engineering.**