Hsp40 and Hsp70 in Membrane Protein Triage

膜蛋白分类中的 Hsp40 和 Hsp70

• 批准号: 10718226
• 负责人: DOUGLAS M CYR
• 金额: $ 42.23万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2027-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10718226
• 关键词: ATP phosphohydrolase; ATP-Binding Cassette Transporters; Adopted; Amyloid; Attention; Autophagocytosis; Autophagosome; Benign; Binding; Biochemical; Biogenesis; Biological Assay; Biosynthetic Proteins; Blindness; Cell Survival; Cell physiology; Cells; Client; Complex; Cystic Fibrosis; Cytoplasm; Cytosol; Data; Detergents; Diameter; Disease; Distal; Docking; Endoplasmic Reticulum; Ensure; Event; Exhibits; Experimental Designs; Face; G-Protein-Coupled Receptors; Goals; Health; Human; Image; Induction of Apoptosis; Inferior; Inherited; Intermediate resistance; Interstitial Lung Diseases; Kinetics; Klinefelter' s Syndrome; Length; Light; Location; Lysosomes; Maintenance; Membrane; Membrane Protein Traffic; Membrane Proteins; Microtubules; Missense Mutation; Molecular Chaperones; Movement; Mutate; Paint; Peptides; Phosphatidylinositols; Phosphotransferases; Poison; Process; Proteins; Proteome; Pulmonary Fibrosis; Quality Control; Resistance; Retinitis Pigmentosa; Role; Series; Shapes; Side; Site; Surface; System; Testing; Thermodynamics; Triage; Tubular formation; WD Repeat; Work; Yeasts; cell motility; conformer; experimental study; farnesylation; human disease; live cell imaging; lysosomal proteins; lysosome membrane; man; meter; misfolded protein; multicatalytic endopeptidase complex; mutant; non-Native; polypeptide; premature; prevent; protein aggregation; protein degradation; protein folding; protein misfolding; proteotoxicity; receptor; receptor function; recruit; restraint; screening; therapy development; ubiquitin-protein ligase

Project Summary: Membrane protein (MP) biogenesis begins in the endoplasmic reticulum (ER) and is a complex process, as domains on both sides of the ER membrane, and within the membrane bilayer, must fold and assemble. MPs understudy include ABC-Transporters, P-Type ATPases, G-protein coupled receptors, and BRICHOS proteins. Missense mutations that cause misfolding and premature degradation of MPs give rise to diseases such as cystic fibrosis, hypogonadotropic hypogonadism, retinitis pigmentosa and idiopathic lung fibrosis. In order to prevent toxic accumulation, misfolded MPs are targeted for ER-associated degradation (ERAD) by E3 ubiquitin ligase complexes. The ER transmembrane Hsp40 DNAJB12 (JB12) recruits cytosolic Hsp70 to the cytoplasmic face of the ER and together these chaperones deliver the misfolded MPs to ERAD machinery. In order for a misfolded protein to be a candidate for ERAD however, it must be competent for extraction from the confines of the ER membrane and delivered to the cytosolic proteasome. Misfolded proteins with structural restraints that prevent entrance into the proteasome necessitate an alternative quality control mechanism to ensure degradation. Misfolded MPs expose surfaces in the ER lumen, membrane, and the cytosol, so the coordinated action of ERQC factors in different locations manage this challenge. Mistakes in MP protein management are fatal when rogue clients adopt a toxic shape that enable rogues to damage membranes and dominantly poison essential cell functions. Hsp70 and Hsp40s act with folding and degradation machines to triage MPs. They shield against proteotoxicity through suppressing aggregation, refolding clients, selection of clients for degradation and regulating flux though protein biosynthetic systems. A major problem to ERQC systems are the MPs that accumulate in thermodynamically stable intermediate states that are non-native and self-associate to form oligomers, amorphous aggregates, and amyloid-like fibrils. Such misfolded conformers bury surfaces that are normally recognized by ERQC factors, and their thermodynamic stability hinders the unfolding events required for their extraction from membranes and degradation in the narrow central cavity of the proteasome. Thermodynamically stable MP intermediates are resistant to ERAD and we discovered that they are degraded by a JB12 dependent ER-phagy mechanism. The overall goal of the experiments included in this proposal is to define nodes of cross-talk between the Hsp70 chaperone system, ERAD and ER-phagy that are essential for cell viability and proteome maintenance.

项目概要： 膜蛋白 (MP) 的生物合成始于内质网 (ER)，是一个复杂的过程，如 内质网膜两侧和膜双层内的结构域必须折叠和组装。国会议员 待研究的蛋白包括 ABC 转运蛋白、P 型 ATP 酶、G 蛋白偶联受体和 BRICHOS 蛋白。 错义突变会导致 MP 错误折叠和过早降解，从而引发以下疾病： 囊性纤维化、低促性腺激素性性腺功能减退症、色素性视网膜炎和特发性肺纤维化。为了 防止毒性积累，错误折叠的 MP 被 E3 泛素靶向进行 ER 相关降解 (ERAD) 连接酶复合物。 ER 跨膜 Hsp40 DNAJB12 (JB12) 将胞质 Hsp70 招募到 ER 的细胞质表面和这些伴侣一起将错误折叠的 MP 传递到 ERAD 机器。在 然而，为了使错误折叠蛋白成为 ERAD 的候选蛋白，它必须能够从 内质网膜的限制并被递送至胞质蛋白酶体。具有结构错误折叠的蛋白质 阻止进入蛋白酶体的限制需要替代的质量控制机制 确保降解。错误折叠的 MP 会暴露 ER 腔、膜和细胞质的表面，因此 不同地点 ERQC 因素的协调行动应对这一挑战。 MP蛋白的错误 当流氓客户采用有毒的形状，使流氓能够破坏膜和 主要毒害基本细胞功能。 Hsp70 和 Hsp40s 与折叠和降解机器一起作用 对议员进行分类。它们通过抑制聚集、重折叠客户、选择 客户通过蛋白质生物合成系统进行降解和调节通量。 ERQC 的一个主要问题 系统是在热力学稳定的中间状态下积累的 MP，这些状态是非自然的和 自缔合形成低聚物、无定形聚集体和淀粉样原纤维。这种错误折叠的构象异构体 通常由 ERQC 因子识别的埋藏表面，其热力学稳定性阻碍了 它们从膜中提取并在狭窄的中央腔中降解所需的展开事件 蛋白酶体。热力学稳定的 MP 中间体能够抵抗 ERAD，我们发现 它们被 JB12 依赖性 ER 吞噬机制降解。实验的总体目标包括 该提案的目的是定义 Hsp70 伴侣系统、ERAD 和 ER-phagy 之间的串扰节点 这对于细胞活力和蛋白质组维持至关重要。