Synthetic Probes of Protein Prenylation

描述（由申请人提供）：类异戊二烯脂质的共价修饰（异戊二烯化）是参与细胞信号传导和癌症的许多蛋白质的关键翻译后事件。这项研究计划的主要目标是设计和测试异戊二烯功能抑制剂，并确定和表征体内法尼基化的蛋白质。本提案中概述的研究将导致制备新的工具来探测异戊烯基转移酶蛋白-法尼基转移酶（FTase）和蛋白-香叶基香叶基转移酶（GGTase-I）的特异性，使异戊烯基功能抑制剂的进一步开发成为可能，并确定新的异戊烯化蛋白作为治疗干预的潜在靶点。通过改变异戊二烯基脂质的化学结构，我们正在开发试剂来探测翻译后修饰的生物学功能。利用异戊二烯基形成异戊二烯基转移酶中肽底物结合位点的实质部分的事实，使我们能够开发异戊二烯基功能的肽选择性抑制剂。这些非天然的类似物可以允许选择性干扰特定的异戊二烯化靶标，并且可以提供先导化合物以减轻与蛋白质异戊二烯化的完全抑制相关的潜在毒性。特别是，非天然的类似物可能是有用的，以获得一个更完整的理解的作用，替代异戊烯化法尼基转移酶抑制剂（FTI）逃避癌基因，如K-Ras。了解现有和未来FTIs和香叶基香叶基转移酶抑制剂（GGTI）的临床作用的关键是FTase和GGTase-I的体内底物的鉴定。我们的创新策略，使用非天然的，可转移的异戊二烯类似物和类似物特异性单克隆抗体，以确定异戊二烯化的细胞蛋白质将提供有价值的信息，异戊二烯化抑制剂的细胞目标。我们希望这些研究能够鉴定出以前未知的异戊二烯化蛋白质。本项目的具体目标是：1）合成法呢基和香叶基香叶基二磷酸类似物，研究蛋白质的异戊二烯化。2)筛选这些化合物的FTase和GGT酶-I的底物特异性和异戊二烯功能抑制剂的发展。3)细胞中异戊二烯化蛋白的鉴定。这些研究的结果可能为治疗癌症的新分子提供线索，并确定开发抗癌疗法的新分子靶点。 公共卫生相关性大量证据表明，通常由异戊二烯基修饰的蛋白质在癌症进展中起核心作用。我们建议设计和测试异戊烯基功能抑制剂，并确定和表征与异戊烯基基团修饰的蛋白质。这些研究的结果可能为治疗癌症的新分子提供线索，并确定新的分子靶点以开发未来的抗癌疗法。

DESCRIPTION (provided by applicant): Covalent modification by isoprenoid lipids (prenylation) is a critical post-translational event for many proteins involved in cellular signaling and cancer. The primary goal of this research program is to design and test prenyl function inhibitors and to identify and characterize proteins that are farnesylated in vivo. The studies outlined in this proposal will result in the preparation of new tools to probe the specificity of the prenyltransferases protein- farnesyltransferase (FTase) and protein-geranylgeranyltransferase (GGTase-I), enable further development of prenyl function inhibitors and identify new prenylated proteins as potential targets for therapeutic intervention. By varying the chemical structure of the prenyl lipid, we are developing reagents to probe the biological function of the posttranslational modification. Taking advantage of the fact that the prenyl group forms a substantial part of the peptide substrate binding site in the prenyltransferases has allowed us to develop peptide selective inhibitors of prenyl function. These unnatural analogues may allow for the selective interference with specific prenylation targets and may provide lead compounds to alleviate the potential toxicity associated with complete inhibition of protein prenylation. In particular, the unnatural analogues may be useful to obtain a more complete understanding of the role that alternative prenylation plays in Farnesyl transferase inhibitor (FTI) evasion by oncogenes such as K-Ras. Critical to understanding the clinical effects of existing and future FTIs and geranylgeranyl transferase inhibitors (GGTIs), is the identification of in vivo substrates of FTase and GGTase-I. Our innovative strategy of using unnatural, transferable prenyl analogues and analogue specific monoclonal antibodies to identify prenylated cellular proteins will provide valuable information on the cellular targets of inhibitors of prenylation. We expect these studies to result in the identification of previously unknown prenylated proteins. The specific aims of this project are: 1) Synthesis of farnesyl and geranylgeranyl diphosphate analogues to study protein prenylation. 2) Screening these compounds for substrate specificity of FTase and GGTase-I and development of prenyl function inhibitors. 3) Identification of prenylated proteins in cells. The results from these studies may provide leads to new molecules to treat cancer and also identify new molecular targets to develop anti-cancer therapies. PUBLIC HEALTH RELEVANCE Substantial evidence points to the central role of proteins normally modified by a prenyl group in cancer progression. We propose to design and test prenyl function inhibitors and to identify and characterize proteins that are modified with prenyl groups. The results from these studies may provide leads to new molecules to treat cancer and also identify new molecular targets to develop future anti-cancer therapies.