Molecular Determinants of AGRP Function

AGRP 功能的分子决定因素

• 批准号: 7065653
• 负责人: GLENN L MILLHAUSER
• 金额: $ 26.22万
• 依托单位: UNIVERSITY OF CALIFORNIA SANTA CRUZ
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-05-15 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7065653
• 关键词: cell surface receptors; chemical stability; chimeric proteins; crosslink; cystine; gene mutation; hormone inhibitor; hormone receptor; melanocyte stimulating hormone; neuropeptide receptor; nuclear magnetic resonance spectroscopy; peptide library; photoactivation; pigmentation; protein engineering; protein folding; protein isoforms; protein structure function; receptor binding; receptor sensitivity; syndecan; tissue /cell culture

DESCRIPTION (provided by applicant): Obesity is one of the greatest public health concerns facing Western society. The condition arises from an imbalance between energy intake and expenditure and contributes to diabetes, cardiovascular disease and cancer. In the brain, a key focal point for control of energy balance is melanocortin signaling, in which there are two ligands, alpha-melanocyte stimulating hormone and Agouti-related protein (AGRP). These molecules act in opposite ways through CNS melanocortin receptors (MCRs) to promote negative and positive energy balance, respectively. AGRP is a multi-domain protein with MCR activity concentrated in its unusual Cys-rich, C-terminal domain. The Pl's laboratory recently determined the structure of this domain and identified regions that are postulated to be essential for AGRP's ability to select MCRs of the central nervous system. The goal of this research program is to significantly broaden the understanding of MCR signaling by determining the molecular features of AGRP that confer its receptor selectivity and control over MCR function. Four Aims are proposed. 1) The structure of the homologous agouti protein that functions in pigmentation will be determined. Comparison of the AGRP and agouti structures will help to identify regions within these signaling molecules that control their respective MCR selectivity. 2) Protein design and photo crosslinking will be used to evaluate the MC receptor regions that make direct contact with AGRP. These studies will test the hypothesis that a specific loop in AGRP mediates MCR recognition. 3) The structure and function of the AGRP N-terminal domain will be determined. Recent findings suggest that this region potentiates MCR antagonism by binding to cell surface syndecans. This concept will be tested using structure-guided pharmacological and transgenic methodologies. 4) The stability and design potential of the novel AGRP cystine-knot structure will be evaluated. The specific scaffold of the AGRP C-terminus has not been previously identified in mammalian proteins. However, studies with plant and invertebrate cystineknots suggest that this scaffold is ideal for pharmacological design. Thermodynamic studies will examine stability and phage display will be used to develop a cystine-knot that selects for receptors outside of the MCR class.

描述（由申请人提供）： 肥胖是西方社会面临的最大公共卫生问题之一。这种情况源于能量摄入和支出之间的不平衡，并导致糖尿病，心血管疾病和癌症。在大脑中，控制能量平衡的关键焦点是黑色皮质素信号传导，其中有两个配体，α-甲状腺细胞刺激激素和与Agouti相关的蛋白（AGRP）。这些分子通过CNS黑色皮质素受体（MCR）以相反的方式作用，分别促进负能量平衡和正能量平衡。 AGRP是一种多域蛋白，其MCR活性集中在其不寻常的Cys富含C末端结构域中。 PL的实验室最近确定了该领域的结构，并确定了假定的区域，这些区域对于AGRP选择中枢神经系统的MCR的能力至关重要。该研究计划的目的是通过确定AGRP的分子特征来显着扩大对MCR信号传导的理解，从而赋予其受体选择性和对MCR功能的控制。提出了四个目标。 1）将确定在色素沉着中起作用的同源agouti蛋白的结构。 AGRP和Agouti结构的比较将有助于确定这些信号分子中控制其各自MCR选择性的区域。 2）蛋白质设计和照片交联将用于评估与AGRP直接接触的MC受体区域。这些研究将检验以下假设：AGRP中的特定循环介导MCR识别。 3）将确定AGRP N末端结构域的结构和功能。最近的发现表明，该区域通过与细胞表面联合体结合来增强MCR拮抗作用。该概念将使用结构引导的药理学和转基因方法进行测试。 4）将评估新型AGRP囊结结构的稳定性和设计潜力。 AGRP C末端的特定支架先前尚未在哺乳动物蛋白中鉴定。但是，对植物和无脊椎动物胱氨酸菌的研究表明，这种支架是药理学设计的理想选择。热力学研究将检查稳定性，噬菌体显示将用于开发胱氨酸结，该结对MCR类外的受体选择。