The C-terminome

描述（由申请人提供）：C 末端通常对于蛋白质功能非常重要，通常包含编码翻译后修饰的短连续肽序列（小基序）、用于运输到特定细胞区室的邮政编码基序以及用于与其他蛋白质和分子结合的小基序。通过对 Minimotif Miner 数据库中 100,000 个小基序的注释，我们的实验室已对超过 1000 个特定于蛋白质羧基 (C) 末端的已知功能性小基序进行了编目。这些 C 末端小基序对于多种生物学功能至关重要。突变可以通过产生疾病状态的单点突变来禁用小基序，并且一些小基序模拟物是 FDA 批准的用于治疗患者的药物。在本提案中，我们寻求识别新的小基序，并将现有信息整合到我们创造的“功能性 C 末端组”中，即 C 末端在所有人类蛋白质中的一般作用。我们首先问一个问题：是否还有重要的 C 端小基序有待发现？在我们的初步研究中，两名研究生进行了生物信息学分析，以确定与杂乱的人类蛋白质组相比，在不同人类蛋白质的 C 末端上过度表达的许多可能的小基序模式。接下来，我们选择了其中的四个小基序，并在试点筛选中，一名本科生使用亲和色谱法和质谱分析法来识别这些小基序的潜在结合伴侣。我们建议通过以下方式扩展这些发现：（1）确定PxP-羧基末端小基序在刺激胞吐作用中的相关性作为案例研究，（2）通过亲和捕获和质谱（LC MS/MS）识别新型C端基序的相互作用子，以及（3）巩固有关功能性C端组的所有已知信息并生成可搜索的网页，用于探索人类蛋白质组中的所有C端小基序。

DESCRIPTION (provided by applicant): The C-termini are often very important for protein function, often containing short contiguous peptide sequences (minimotifs) that encode post-translational modification, zipcode motifs for trafficking to specific cell compartments, and minimotifs for binding to other proteins and molecules. Through our annotation of 100,000s of minimotifs in the Minimotif Miner database our lab has catalogued >1000 known functional minimotifs specific to the carboxy (C)-termini of proteins. These C-terminal minimotifs are critica for a wide array of biological functions. Mutations can disable minimotifs by a single point mutation producing disease states and some minimotif mimetics are FDA-approved drugs used to treat patients. In this proposal we seek to identify new minimotifs and consolidate existing information into what we coin the "functional C-terminome", the general role of the C-terminus in all human proteins. We first ask the question: Are there important C-terminal minimotifs that remain to be discovered? In our preliminary studies two graduate students performed a bioinformatic analysis to identify many possible minimotif patterns that overrepresented on the C- termini of different human proteins when compared to a scrambled human proteome. We next selected four of these minimotifs and in a pilot screen an undergraduate used affinity chromatography followed by mass spectrometry to identify potential binding partners for these minimotifs. We propose to expand upon these findings by (1) determining the relevance of the PxP-carboxy terminal minimotif in stimulate exocytosis as a case study, (2) identify interactors of novel C-terminal motifs by affinity capture and mass spectrometry (LC MS/MS), and (3) to consolidate all known information about the functional C-terminome and generate a searchable webpage for exploring all C-terminal minimotifs in the human proteome.