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Structural basis of KATP channel gating

KATP通道门控的结构基础

基本信息

批准号：
10549857
负责人：
Show-Ling Shyng
金额：
$ 43.82万
依托单位：
OREGON HEALTH & SCIENCE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-02-07 至 2025-01-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10549857
关键词：
ATP-Binding Cassette Transporters Affect Antidiabetic Drugs Binding Biochemical Biogenesis Blood Vessels Brain CRSP3 gene Carbamazepine Cells Cellular Metabolic Process Chemicals Complex Cryoelectron Microscopy Data Defect Detergents Developmental Delay Disorders Dimerization Disease Distal Drug Design Epilepsy Functional disorder Funding Genes Genetic Polymorphism Glucose Glyburide Goals Grant Health Heart Hormone secretion Human Hypoglycemia Impairment Ion Channel Knowledge Lead Ligands Mediating Membrane Membrane Proteins Methods MgADP MgATP Molecular Molecular Chaperones Monitor Mutation N-terminal Non-Insulin-Dependent Diabetes Mellitus Nucleotides Outcome Persistent Hyperinsulinemia Hypoglycemia of Infancy Pharmaceutical Preparations Phosphatidylinositol 4,5-Diphosphate Physiological Positioning Attribute Potassium Potassium Channel Publishing Regulation Resolution Review Literature Risk Structure Structure of beta Cell of islet Structure-Activity Relationship Surface Syndrome Testing Therapeutic Transmembrane Domain biochemical tools biophysical tools conformational conversion crosslink design gain of function mutation glucose metabolism hormone regulation human disease improved inhibitor innovation insulin secretion inward rectifier potassium channel ischemic injury loss of function mutation molecular dynamics mutant nanodisk neonatal diabetes mellitus novel particle pharmacologic preservation protein complex reconstitution repaglinide sulfonylurea receptor trafficking

项目摘要

PROJECT SUMMARY ATP-sensitive potassium (KATP) channels couple cell metabolism to membrane excitability and are critical for many physiological functions. They are unique membrane protein complexes formed by four inwardly rectifying K+ channel (Kir6.1 or Kir6.2) subunits and four sulfonylurea receptor (SUR1 or SUR2) subunits. This grant is focused on KATP channels consisting of Kir6.2 and SUR1, which have a key role in glucose-stimulated insulin secretion in pancreatic β-cells. Loss-of-function mutations in these channels cause congenital hyperinsulinism and hypoglycemia, whereas gain-of-function mutations cause neonatal diabetes and in severe cases DEND (Developmental delay, Epilepsy, and Neonatal Diabetes) syndrome. In addition, KATP gene polymorphisms increase risk for type 2 diabetes. Our long-term goal is to understand the structure-function relationship of KATP channels in order to develop mechanism-based therapies for disease caused by KATP dysfunction. Over the past three funding cycles, we have made significant progress towards this goal. Most particularly, using single-particle cryo-electron microscopy (cryoEM) we recently obtained high-resolution structures of the channel bound with the physiological inhibitor ATP and the anti-diabetic drug glibenclamide (glyburide). This opened a new chapter for the field, enabling us to understand the structural basis of KATP channel assembly and gating in health and disease, at near atomic detail and in the context of full channel structure. Our group is uniquely positioned to help lead this effort by integrating our cryoEM capability with the extensive molecular, biochemical, and biophysical tools and knowledge we have amassed over the course of this grant. In this renewal application, we propose to tackle the most important yet challenging problems remaining in the field. Our overarching hypothesis is that SUR1 assembles with and regulates the function of Kir6.2 through specific structural interactions that are regulated by physiological and pharmacological ligands. We will use a combination of structural, molecular dynamics simulation and functional approaches to test the hypothesis in three interwoven but independent Specific Aims. (1) Elucidate KATP channel assembly mechanisms guided by our cryoEM structures. (2) Identify and monitor interactions between SUR1, Kir6.2, and ligands that are critical for channel opening and closure to understand the structural mechanisms governing channel gating. (3) Determine open state structures of KATP channels by cryoEM to understand the conformational transition during gating. The proposal has a strong scientific premise built on our rigorous preliminary and published studies as well as a careful review of the literature. The proposal is innovative as it will generate new structures and test conceptually novel mechanistic hypotheses on channel gating and assembly emanated from the recent cryoEM structures. Successful outcome will have significant impact on advancing our structural knowledge of channel regulation to facilitate mechanistic drug design for disease caused by KATP channel dysfunction. Further, the outcome will have broad implications for many other ABC transporters and ion channels important for human health.

项目总结