Synthetic Probes of Protein Prenylation

描述(由申请人提供)：异戊二烯类脂的共价修饰(异戊二烯基化)对于参与细胞信号和癌症的许多蛋白质来说是一个关键的翻译后事件。这项研究计划的主要目标是设计和测试戊烯功能抑制剂，并鉴定和表征体内法尼化的蛋白质。这项建议中概述的研究将导致准备新的工具来探索异丙烯基转移酶蛋白-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，使异丙烯基功能抑制剂的进一步开发成为可能，并确定新的异丙烯基化蛋白作为潜在的治疗干预靶点。通过改变戊烯基脂的化学结构，我们正在开发试剂来探索翻译后修饰的生物学功能。利用戊烯基基在戊烯基转移酶中形成了相当一部分的肽底物结合部位这一事实，我们可以开发出戊烯基功能的多肽选择性抑制剂。这些非天然类似物可能允许选择性干扰特定的预烯基化靶标，并可能提供先导化合物来减轻与完全抑制蛋白质预烯基化相关的潜在毒性。特别是，非天然类似物可能有助于更全面地了解交替预烯基化在K-RAS等癌基因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体内FTase和GGTase-I底物的鉴定。我们的创新策略是使用非天然的、可转移的戊烯类似物和类似的特异性单抗来鉴定预烯基化的细胞蛋白，这将为预烯基化抑制剂的细胞靶标提供有价值的信息。我们期望这些研究能够鉴定出以前未知的前烯基化蛋白。本项目的具体目标是：1)合成法尼基和香叶基二磷酸类似物，研究蛋白质的戊烯基化反应。2)对这些化合物进行FTase和GGTase-I底物专一性筛选及戊烯功能抑制剂的开发。3)细胞内预烯基化蛋白质的鉴定。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，通常由戊烯基团修饰的蛋白质在癌症进展中起着中心作用。我们建议设计和测试戊烯基功能抑制剂，并鉴定和表征被戊烯基修饰的蛋白质。这些研究的结果可能会为治疗癌症的新分子提供线索，并为开发未来的抗癌疗法确定新的分子靶点。

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.