AR COBRE: PROTEIN TARGETING

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 信号识别颗粒(SRP)及其受体在生命的各个领域发挥作用。它们是一个复杂的蛋白质靶向系统的组成部分，该系统将新合成的蛋白质输送到三种不同的膜系统中的转运蛋白(蛋白转运酶)：细菌细胞质膜、内质网和叶绿体类囊体膜。人类中SRP靶向/易位系统的故障与特发性炎症性肌病、糖尿病和结肠癌有关。在细菌中，SRP功能是细菌病原体成功的核心。SRP靶向的复杂性继续拖慢了SRP如何靶向并将蛋白质转移到位于靶膜上的转位机制的详细机制模型。新近发现的叶绿体SRP的独特结构和功能特征为研究SRP靶向机制提供了前所未有的机会，使用其他基于SRP的靶向模型无法获得或不易应用的工具和分析。戈福斯领导和亨利指导下的一个跨学科团队将应用先进的蛋白质组学和蛋白质结构分析以及更传统的分子和生化方法，以(1)确定SRP/受体/转位酶复合体组件之间的蛋白质相互作用，(2)确定对SRP与受体和转位酶通信至关重要的蛋白质的结构，以及(3)确定特定蛋白质/蛋白质相互作用在重建靶向/转位机制的每一步骤的分析中的功能。拟议工作的完成将有助于理解以下相互作用：(I)靶向成分参与适当和可用的转位机制，(Ii)调节底物从SRP到转位酶的释放，以及(Iii)从转位酶控制靶向成分的释放。我们的结果将广泛影响我们对蛋白质靶向和插入功能的分子机器的理解。此外，通过这种跨学科方法获得的洞察力将提供必要的比较信息，以确定以可持续发展战略为基础的目标确定的共同机制原则。正是这些共同的特征无疑确保了忠实的蛋白质靶向和插入，尽管进化力量改变了SRP靶向/插入机制，使其在各种生物体和细胞环境中高效运行。

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. Signal recognition particles (SRPs) and their receptors function in every domain of life. They are components of an elaborate protein targeting system that delivers newly synthesized proteins to transporters (protein translocases) present in three different membrane systems; the bacterial cytoplasmic membrane, the endoplasmic reticulum, and the chloroplast thylakoid membrane. Malfunction of the SRP targeting/translocation system in humans is implicated in idiopathic inflammatory myopathies, diabetes mellitus, and colon cancer. In bacteria, SRP function is central to the success of bacterial pathogens. Complexities of SRP targeting continue to slow a detailed mechanistic model for how SRP targets and transfers proteins to translocation machinery located in the target membrane. Unique structural and functional features of the more recently discovered chloroplast SRP provide an unprecedented opportunity to examine the SRP targeting mechanism using tools and assays not available or not easily applied to other SRP-based targeting models. A transdisciplinary team led by Goforth and under the mentorship of Henry will apply advanced proteomics and protein structure analysis with more traditional molecular and biochemical approaches in order to (1) identify protein interactions between components of a SRP/receptor/translocase complex, (2) determine the structure of proteins critical for SRP to communicate with receptor and translocase, and (3) determine the function of specific protein/protein interactions in assays that reconstitute each step of the targeting/translocation mechanism. Completion of the proposed work will provide understanding of interactions that (i) are needed for targeting components to engage appropriate and available translocation machinery, (ii) regulate substrate release from SRP to the translocase, and (iii) control release of targeting components from the translocase. Our resulsts will broadly impact our understanding of the molecular machines that function in protein targeting and insertion. Moreover, insight gained through this transdisciplinary approach will provide needed comparative information to identify common mechanistic principals of SRP-based targeting. It is these common features that undoubtedly ensure faithful protein targeting and insertion despite evolutionary forces that have altered the SRP targeting/insertion machinery for efficient operation in a diverse array of organisms and cellular environments.