The C-terminome

描述(申请人提供)：C-末端通常对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(最小核苷酸)，用于运输到特定细胞室的Zipcode基序，以及用于与其他蛋白质和分子结合的最小核苷酸。通过我们在Minimotf Miner数据库中对100,000个最小核苷酸的注释，我们的实验室已经编目了1000个特定于蛋白质的羧基(C)末端的已知功能最小核苷酸。这些C-末端最小核苷酸对于广泛的生物功能是关键的。突变可以通过单点突变使最小莫替夫失效，从而产生疾病状态，一些最小莫替夫模拟物是FDA批准的用于治疗患者的药物。在这项建议中，我们试图确定新的最小核苷酸，并将现有信息整合到我们所称的“功能C-末端组”中，即C-末端在所有人类蛋白质中的一般作用。我们首先问这个问题：有没有重要的C-末端最小信号有待发现？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-末端过度表达的许多可能的最小核苷酸模式。接下来，我们选择了四个这些最小核苷酸，并在试点筛选中，本科学生使用亲和层析和质谱分析来确定这些最小核苷酸的潜在结合伙伴。我们建议通过(1)确定PxP-羧基末端最小核苷酸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学(LC-MS/MS)识别新的C-末端基序的相互作用，以及(3)整合关于功能C-末端组的所有已知信息，并生成一个可搜索的网页来探索人类蛋白质组中的所有C-末端最小核苷酸，以扩展这些发现。

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.