A conserved mechanism couples cytosolic domain movements to pore gating in the TRPM2 channel

• 成果类型: Article
• 署名作者: Toth, Balazs; Jiang, Yuefeng; Szollosi, Andras; Zhang, Zhe; Csanady, Laszlo
• 署名单位: Semmelweis University; Semmelweis University; Semmelweis University; Peking University; Peking University
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-9043
• DOI: 10.1073/pnas.2415548121
• 发表日期: 2024-11-12
• 关键词: peroxide-induced toxicity; hydrogen-peroxide; ion-channel; adp-ribose; temperature; activation; sensor

摘要

Transient Receptor Potential Melastatin 2 (TRPM2) cation channels contribute to immunocyte activation, insulin secretion, and central thermoregulation. TRPM2 opens upon binding cytosolic Ca2+ and ADP ribose (ADPR). We present here the 2.5 & Aring; cryo- electronmicroscopy structure of TRPM2 from Nematostella vectensis (nvTRPM2) in a lipid nanodisc, complexed with Ca2+ and ADPR-2 '- phosphate. Comparison with nvTRPM2 without nucleotide reveals that nucleotide binding- induced movements in the protein's three core layers deconvolve into a set of rigid- body rotations conserved from cnidarians to man. By covalently crosslinking engineered cysteine pairs we systematically trap the cytosolic layers in specific conformations and study effects on gate opening/closure. The data show that nucleotide binding in Layer 3 disrupts inhibitory intersubunit interactions, allowing rotation of Layer 2 which in turn expands the gate located in Layer 1. Channels trapped in that activated state are no longer nucleotide dependent, but are opened by binding of Ca2+ alone.