Synthetic Probes of Protein Prenylation

描述（由申请人提供）：类异戊二烯脂的共价修饰（戊烯酰化）是许多参与细胞信号传导和癌症的蛋白质的关键翻译后事件。本研究计划的主要目标是设计和测试戊烯基功能抑制剂，并鉴定和表征在体内被法炔基化的蛋白质。本提案中概述的研究将导致制备新的工具来探测烯丙基转移酶蛋白-法尼基转移酶（FTase）和蛋白-香叶基转移酶（GGTase-I）的特异性，从而进一步开发烯丙基功能抑制剂，并确定新的烯丙基化蛋白作为治疗干预的潜在靶点。通过改变烯丙基脂质的化学结构，我们正在开发试剂来探测翻译后修饰的生物学功能。在戊烯基转移酶中，戊烯基是肽底物结合位点的重要组成部分，利用这一事实，我们开发了戊烯基功能的肽选择性抑制剂。这些非天然类似物可能允许选择性干扰特定的烯酰化靶点，并可能提供先导化合物来减轻与完全抑制蛋白质烯酰化相关的潜在毒性。特别是，非自然类似物可能有助于更全面地了解替代戊烯酰化在癌基因（如K-Ras）逃避法尼基转移酶抑制剂（FTI）中所起的作用。了解现有和未来FTIs和香叶基香叶基转移酶抑制剂（GGTIs）的临床效果的关键是鉴定FTase和GGTase-I的体内底物。我们的创新策略是使用非天然的、可转移的戊烯基类似物和类似物特异性单克隆抗体来鉴定戊烯基化的细胞蛋白，这将为戊烯基化抑制剂的细胞靶点提供有价值的信息。我们期望这些研究能够鉴定出以前未知的烯丙基化蛋白。本课题的具体目的是：1)合成法尼基和香叶基二磷酸类似物，研究蛋白质烯酰化。2)筛选这些化合物对FTase和GGTase-I的底物特异性，开发戊烯基功能抑制剂。3)细胞中烯丙基化蛋白的鉴定。这些研究的结果可能为治疗癌症的新分子提供线索，也可能为开发抗癌疗法提供新的分子靶点。

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.