Structure of an open KATP channel reveals tandem PIP2 binding sites mediating the Kir6.2 and SUR1 regulatory interface

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: March 20, 2024

Abstract ATP-sensitive potassium (K ATP ) channels, composed of four pore-lining Kir6.2 subunits and regulatory sulfonylurea receptor 1 (SUR1) subunits, control insulin secretion in pancreatic β-cells. K channel opening is stimulated by PIP 2 inhibited ATP. Mutations that increase reduce inhibition cause neonatal diabetes. Although considerable evidence has implicated a role for function, previously solved open-channel structures have lacked bound , mechanisms which regulates channels remain unresolved. Here, we report the cryoEM structure harboring diabetes mutation Kir6.2-Q52R, open conformation, to amphipathic molecules consistent with natural C18:0/C20:4 long-chain PI(4,5)P at two adjacent binding sites between SUR1 Kir6.2. The canonical site conserved among -gated Kir channels. non-canonical forms interface SUR1. Functional studies demonstrate both determine activity. pore associated twist cytoplasmic domain rotation N-terminal transmembrane SUR1, widens inhibitory pocket disfavor binding. conformation particularly stabilized Kir6.2-Q52R residue through cation-π bonding SUR1-W51. Together, these results uncover cooperation gating, explain antagonistic regulation ATP, provide putative mechanism stabilizes an

Language: Английский

---

Mechanistic insights on KATP channel regulation from cryo-EM structures

The Journal of General Physiology, Journal Year: 2022, Volume and Issue: 155(1)

Published: Nov. 9, 2022

Gated by intracellular ATP and ADP, ATP-sensitive potassium (KATP) channels couple cell energetics with membrane excitability in many types, enabling them to control a wide range of physiological processes based on metabolic demands. The KATP channel is complex four subunits from the Kir family, Kir6.1 or Kir6.2, sulfonylurea receptor subunits, SUR1, SUR2A, SUR2B, ATP-binding cassette (ABC) transporter family. Dysfunction underlies several human diseases. importance these health disease has made attractive drug targets. How interact one another how ligands regulate activity have been long-standing questions field. In past 5 yr, steady stream high-resolution structures published using single-particle cryo-electron microscopy (cryo-EM). Here, we review advances bring our understanding regulation pharmacological ligands.

Language: Английский

---

Dynamic duo: Kir6 and SUR in K _ATP channel structure and function

Channels, Journal Year: 2024, Volume and Issue: 18(1)

Published: March 15, 2024

K

Language: Английский

---

KATP channels in focus: Progress toward a structural understanding of ligand regulation

Current Opinion in Structural Biology, Journal Year: 2023, Volume and Issue: 79, P. 102541 - 102541

Published: Feb. 20, 2023

Language: Английский

---

Non-radioactive Rb+ Efflux Assay for Screening KATP Channel Modulators

Methods in molecular biology, Journal Year: 2024, Volume and Issue: unknown, P. 191 - 210

Published: Jan. 1, 2024

---

AI-Based Discovery and CryoEM Structural Elucidation of a KATP Channel Pharmacochaperone

Published: March 11, 2025

Pancreatic K ATP channel trafficking defects underlie congenital hyperinsulinism (CHI) cases unresponsive to the opener diazoxide, mainstay medical therapy for CHI. Current clinically used inhibitors have been shown act as pharmacochaperones and restore surface expression of mutants; however, their therapeutic utility impaired CHI is hindered by high-affinity binding, which limits functional recovery rescued channels. Recent structural studies channels employing cryo-electron microscopy (cryoEM) revealed a promiscuous pocket where several known bind. The knowledge provides framework discovering with desired reversible inhibitory effects permit Using an AI-based virtual screening technology AtomNet® followed validation, we identified novel compound, termed Aekatperone, exhibits chaperoning on mutations. Aekatperone reversibly inhibits activity half-maximal concentration (IC 50 ) ∼ 9 μM. Mutant cell showed upon washout compound. CryoEM structure bound distinct binding features compared high affinity inhibitor pharmacochaperones. Our findings unveil pharmacochaperone enabling promising caused defects.

Language: Английский

---

AI-based discovery and cryoEM structural elucidation of a KATP channel pharmacochaperone

eLife, Journal Year: 2025, Volume and Issue: 13

Published: March 26, 2025

Pancreatic K ATP channel trafficking defects underlie congenital hyperinsulinism (CHI) cases unresponsive to the opener diazoxide, mainstay medical therapy for CHI. Current clinically used inhibitors have been shown act as pharmacochaperones and restore surface expression of mutants; however, their therapeutic utility trafficking-impaired CHI is hindered by high affinity binding, which limits functional recovery rescued channels. Recent structural studies channels employing cryo-electron microscopy (cryoEM) revealed a promiscuous pocket where several known bind. The knowledge provides framework discovering with desired reversible inhibitory effects permit Using an AI-based virtual screening technology AtomNet followed validation, we identified novel compound, termed Aekatperone, exhibits chaperoning on mutations. Aekatperone reversibly inhibits activity half-maximal concentration (IC 50 ) ~9 μM. Mutant cell showed upon washout compound. CryoEM structure bound distinct binding features compared inhibitor pharmacochaperones. Our findings unveil pharmacochaperone enabling promising caused defects.

Language: Английский

---

Cholesterol Concentration in Cell Membranes and its Impact on Receptor–Ligand Interaction: A Computational Study of ATP-Sensitive Potassium Channels and ATP Binding

The Journal of Membrane Biology, Journal Year: 2025, Volume and Issue: unknown

Published: March 26, 2025

Abstract This work describes a computer study that looks at how different amounts of cholesterol (0%, 25%, and 50%) in cell membranes change the relationship between ATP K channel. could explain why pancreatic beta-cells secrete insulin differently. We use simulations molecular dynamics, calculations binding free energy, an integrated oscillator model to look electrical activity beta-cells. There is need for this kind multiscale approach right now because plays part metabolic syndrome early type 2 diabetes. Our results showed increase concentration membrane affects electrostatic interactions channel, especially with charged residues site. Cholesterol can influence properties membrane, including its local charge distribution near environment around ATP-binding site, increasing affinity channel as our indicated from 0 25 50% (− 141 − 113 kJ/mol, respectively). Simulating channels beta-cell indicates even minimal produce hyperinsulism. The answers important research question about structure function and, turn, releases common feature stages Graphical

Language: Английский

---

Bayliss–Starling Prize Lecture: K_ATP channel pathophysiology – a whole‐body odyssey

The Journal of Physiology, Journal Year: 2025, Volume and Issue: unknown

Published: May 31, 2025

Abstract First identified 40 years ago in cardiac myocytes, ATP‐sensitive potassium (K ATP ) channels have been found almost all excitable tissues, with paradigmatic inhibition by and activation ADP underlying their physiological role coupling cellular metabolism to electrical activity. Cloning of the genes, 30 ago, revealed unique assembly as four Kir6.x pore‐forming subunit proteins sulfonylurea receptor (SURx) has since led discovery a spectrum monogenic diseases resulting from gain‐ (GOF) or loss‐of‐function (LOF) mutations, turn leading recognition novel roles pathophysiological consequences throughout body. With this perspective, lecture represents personal view these discoveries potential for future insights. image

Language: Английский

---

Structural Insights into ATP-Sensitive Potassium Channel Mechanics: A Role of Intrinsically Disordered Regions

Journal of Chemical Information and Modeling, Journal Year: 2023, Volume and Issue: 63(6), P. 1806 - 1818

Published: Feb. 6, 2023

Commonly used techniques, such as CryoEM or X-ray, are not able to capture the structural reorganizations of disordered regions proteins (IDR); therefore, it is difficult assess their functions in based exclusively on experiments. To fill this gap, we computational molecular dynamics (MD) simulation methods IDR and trace biological function-related interactions Kir6.2/SUR1 potassium channel. This ATP-sensitive octameric complex, one critical elements insulin secretion process human pancreatic β-cells, has four five large, fragments. Using unique MD simulations full channel present an in-depth analysis discuss possible they could have system. Our results confirmed crucial role N-terminus Kir6.2 fragment L0-loop SUR1 protein transfer mechanical signals between domains that trigger release. Moreover, show presence IDRs affects natural ligand binding. research takes us step further toward understanding action vital complex.

Language: Английский

---