The C-terminome

描述（由申请人提供）：c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（minimotifs），运输到特定细胞区室的zipcode基序，以及与其他蛋白质和分子结合的minimotifs。通过我们对Minimotif Miner数据库中100,000个minimotifs的注释，我们的实验室已经编目了bb1000个已知的针对蛋白质羧基(C)末端的功能性minimotifs。这些c端微小基序对多种生物功能至关重要。突变可以通过单点突变使微小基序失效，从而产生疾病状态，一些微小基序模拟物是fda批准用于治疗患者的药物。在这个提议中，我们试图识别新的微小基序，并将现有的信息整合到我们所创造的“功能性c端”中，即c端在所有人类蛋白质中的一般作用。我们首先要问的问题是：是否还有重要的c端微小基序有待发现？在我们的初步研究中，两名研究生进行了生物信息学分析，以确定与混乱的人类蛋白质组相比，在不同人类蛋白质的C端过度代表的许多可能的微小基序模式。接下来，我们选择了四个这样的微小基序，在一个试点筛选中，一个本科生使用亲和色谱法和质谱法来识别这些微小基序的潜在结合伙伴。我们建议通过以下方法来扩展这些发现：(1)确定pxp -羧基端微小基序与刺激胞外作用的相关性作为案例研究；(2)通过亲和力捕获和质谱（LC MS/MS）鉴定新型c -末端基序的相互作用；(3)整合所有已知的功能性c -末端基序的信息，并生成一个可搜索的网页，用于探索人类蛋白质组中所有c -末端微小基序。

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.