Initiation and Regulation of Prophenoloxidase Activation

原酚氧化酶激活的启动和调节

• 批准号: 6871675
• 负责人: HAOBO JIANG
• 金额: $ 26.38万
• 依托单位: OKLAHOMA STATE UNIVERSITY STILLWATER
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-03-01 至 2009-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6871675
• 关键词: Manduca; cofactor; complementary DNA; endopeptidases; enzyme activity; enzyme induction /repression; hemolymph; microorganism immunology; molecular cloning; monophenol monooxygenase; protein sequence; recombinant proteins; serine proteinases

DESCRIPTION (provided by applicant): The prophenoloxidase activation pathway in insects is an integral component of the host immune system against microbial infection. Phenoloxidase (PO) catalyzes the production of quinones that are precursors for cuticle sclerotization, wound healing, and melanotic encapsulation of invading microorganisms. Due to high reactivity and cytotoxicity of quinones, proteolytic activation of prophenoloxidase (PPO) has to be tightly regulated as a potent, local reaction against nonself. In insect vectors of human diseases, initiation and control of this process may be interfered by proteins from pathogens or parasites. Knowledge of the activation process from biochemical model insects such as Manduca sexta will be useful for understanding and manipulating a similar system in blood-feeding insects that transmit human diseases. Three PPO-activating proteinases (PAPs) isolated from M. sexta require cleaved serine proteinase homologs (SPHs) for PPO activation. Molecular cloning and sequence comparison indicate that the PAPs and SPHs all contain regulatory clip domains. We plan to expand our current research on PAPs to acquire in-depth understandings of the molecular mechanisms that trigger and regulate the PPO activation in M. sexta. The specific aims of this project are: 1) Characterization of HP14, an initiation proteinase of the PPO activation cascade; 2) Isolation and cDNA cloning of an activating enzyme for proSPH-1 and proSPH-2; 3) Functional analysis of the clip domains in PAP-2.

描述（由申请人提供）：昆虫中的预防烯氧化酶激活途径是针对微生物感染的宿主免疫系统的组成部分。苯酚氧化酶（PO）催化了奎因酮的产生，这是表皮硬化，伤口愈合和入侵微生物的黑色素封装的前体。由于奎因酮的反应性高和细胞毒性，必须严格调节预防酶（PPO）的蛋白水解活化，作为对非sef的有效的局部反应。在人类疾病的昆虫载体中，病原体或寄生虫的蛋白质可能会干扰该过程的启动和控制。了解来自生化模型昆虫（例如甘达·塞克斯塔）的激活过程将有助于理解和操纵传播人类疾病的喂食昆虫中的类似系统。从M. sexta分离出的三个PPO激活蛋白酶（PAP）需要裂解的丝氨酸蛋白酶同源物（SPH）进行PPO激活。分子克隆和序列比较表明，PAP和SPH都包含调节夹域。我们计划扩大目前对PAP的研究，以获取对触发和调节M. Sexta中PPO激活的分子机制的深入理解。该项目的具体目的是：1）HP14的表征，HP14是PPO激活级联的启动蛋白酶； 2）对Plissph-1和Prosph-2的激活酶的分离和cDNA克隆； 3）PAP-2中夹域的功能分析。