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Mechanisms of Gamma-Secretase

γ-分泌酶的机制

基本信息

批准号：
9566224
负责人：
Michael S Wolfe
金额：
$ 29.16万
依托单位：
UNIVERSITY OF KANSAS LAWRENCE
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-09-20 至 2021-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9566224
关键词：
Active Sites Address Affinity Alanine Alzheimer&apos s Disease Amino Acids Amyloid beta-Protein Amyloid beta-Protein Precursor Architecture Aspartate Binding Biochemical Biology C-terminal Carboxypeptidase Chemicals Cleaved cell Collaborations Complex Crystallization Cysteine Disease Dissociation Disulfides Docking Enzymes Goals Homologous Gene Hybrids Integral Membrane Protein Laboratories Length Lipid Bilayers Malignant Neoplasms Medicine Membrane Membrane Proteins Molecular Conformation Multienzyme Complexes Mutagenesis Pathogenesis Peptide Hydrolases Peptides Play Proteins Proteolysis Resolution Role Series Signal Transduction Site Structure Structure-Activity Relationship Substrate Domain Surface Plasmon Resonance Techniques Testing Time Transmembrane Domain Universities Water Work analog design experimental study gamma secretase inhibitor/antagonist notch protein presenilin rhomboid structural biology

项目摘要

Project Summary γ-Secretase is a membrane-embedded protease complex with presenilin as its catalytic component. This complex cleaves the transmembrane domains (TMDs) of a wide variety of type I integral membrane proteins after their ectodomain release by sheddases. Among these substrates are Notch and the amyloid β-protein precursor (APP). TMD cleavage of Notch receptors is part of cell signaling mechanisms essential to metazoan biology and dysregulated in cancer, and TMD cleavage of APP to amyloid β-protein (Aβ) is essential to the pathogenesis of Alzheimer's disease (AD). The overarching goal of this proposal is to elucidate how intramembrane proteolysis is accomplished by γ-secretase. Toward this end, we will address three central open questions regarding the mechanism of this complex enzyme that is so critical in biology and medicine. (1) How does γ-secretase recognize substrates? As the enzyme cleaves the TMD of substrate, we seek to understand the role of helicity in substrate recognition. In addition, we have used a recent high-resolution structure of the protease complex to design experiments to identify the gate on presenilin that allows access of substrate TMD into the active site. (2) How does γ-secretase carry out processive proteolysis? γ-Secretase initially cleaves substrates within their TMDs close to the cytosolic interface, followed by processive carboxypeptidase trimming resulting in secreted peptides. We will address whether the longer Aβ peptide intermediates have higher affinity for the enzyme, allowing more time for trimming, than shorter Aβ peptides. We will also address whether peptide product intermediates remain bound or dissociate from the enzyme prior to further trimming. (3) How does γ-secretase unwind helical TMD substrates for proteolysis? We have designed a series of hybrid helical peptide/transition-state analog inhibitors to mimic the TMD substrate bound to the enzyme in the transition state. In collaboration with a leading structural biology lab, structure elucidation of the most potent hybrid inhibitor bound to active γ-secretase will be determined to understand the structural basis of the γ-secretase mechanism of action.

项目总结