Structure and Function of ICMT Methyltransferase

描述（由申请人提供）：CaaX基序的翻译后修饰提供了一种调节细胞信号传导蛋白（包括Ras）的方法。CaaX基序的加工涉及三种顺序作用的酶：蛋白质异戊二烯基转移酶、异戊二烯基-CaaX蛋白酶和异戊二烯基半胱氨酸羧基甲基转移酶（ICMT）。异戊烯基转移酶的药理学抑制已显示出作为抗癌疗法的效用。ICMT的生物化学抑制赋予Ras依赖性致癌转化抗性。ICMT的药理学抑制剂缺乏，但将为治疗开发提供途径。本研究旨在通过对ICMT结构和功能的研究，更好地了解其酶促机制、结构，并制定抑制策略。该过程将包括ICMT的纯化和溶解，伴随酶分析以确保活性并确定ICMT的作用机制。此外，人ICMT的结构将被确定用于帮助酶抑制剂的设计和进一步理解蛋白质的ICMT甲基化的分子机制。这些数据将提供ICMT的生物化学和结构特性的详细描述，重点是抑制。

DESCRIPTION (provided by applicant): Post-translational modification of CaaX motifs provides a means to regulate cell signaling proteins, including Ras. The processing of CaaX motifs involves three sequentially acting enzymes: protein prenyltransferases, prenyI-CaaX proteases, and isoprenylcysteine carboxyl methyltransferase (ICMT). Pharmacologic inhibition of prenyltransferase has shown utility as an anti-cancer therapy. Biochemical inhibition of ICMT confers resistance to Ras dependent oncogenic transformation. Pharmacologic inhibitors of ICMT are lacking but would provide an avenue for therapeutic development. This study proposes to study the structure and function of ICMT to better understand its enzymatic mechanism, structure, and to develop inhibition strategies. This process will include purification and solublization of ICMT, accompanied by enzymatic analysis to insure activity and determine the mechanism of action for ICMT. Additionally the structure of human ICMT will be determined for use in aiding enzyme inhibitor design and further understanding of the molecular mechanism of ICMT methylation of proteins. This data will provide a detailed description of the biochemical and structural properties of ICMT, with a focus on inhibition.