Activation and Inhibition Mechanisms of Calcium-Activated Nonselective Cation Channels

项目摘要 钙激活的非选择性阳离子(CAN)通道是为数不多的转化为 与大多数离子相反，细胞内钙信号转导到膜电位的变化 直接或间接利用膜电位调节细胞内钙离子的通道 发信号。这一独特的特性使CAN通道在许多组织和 器官。虽然CAN通道的存在几十年来就已为人所知，但最近的证据表明 已经确定一价阳离子渗透性的TRPM4和TrPM5是长期寻找的 用于CAN频道。事实上，大量的TRPM4突变与严重的人类疾病有关， 例如，心脏传导阻滞、布拉加达综合征、PSEK(一种皮肤病)。尽管他们 功能意义，对控制TRPM4和5的分子机制知之甚少 渠道活动。Ca2是唯一已知的对它们的生理激活剂，尽管膜 电位也调节通道活动，但仅在有钙离子存在的情况下。然而，虽然 低温电子显微镜研究已经确定了钙结合部位，即钙和电压是如何激活的 TRPM4和5频道仍然未知。此外，虽然大多数已知的致病因素 TRPM4突变导致功能获得表型，没有有效的TRPM4&5抑制剂是 目前可用。基于我们对TRPM4、钙和电压的初步功能数据 激活，我们发现了导致人类皮肤病的新的TRPM4突变，一种新的 显示皮肤表型的致病突变通道CRISPR小鼠模型，以及我们的 最近发现了一种新的TRPM4抑制过程，我们计划使用多学科 旨在揭示TRPM4&5激活和激活的基本机制 抑制力。

Project Summary Ca2+-activated nonselective cation (CAN) channels are among a few ion channels that convert intracellular Ca2+ signaling into changes in membrane potential, in contrast to most ion channels that directly or indirectly use membrane potential to regulate intracellular Ca2+ signaling. This unique property allows CAN channels to play critical roles in many tissues and organs. While the existence of CAN channels has been known for decades, recent evidence has established that monovalent cation-permeable TRPM4 and TRPM5 are the long sought for CAN channels. Indeed, numerous TRPM4 mutations are linked to severe human diseases, e.g., cardiac conduction block, Bragada syndrome, PSEK (a skin disease). Despite their functional significance, little is known about the molecular mechanisms governing TRPM4&5 channels activity. Ca2+ is the only known physiological activator for them, though membrane potential also regulates channel activity but only in the presence of Ca2+. However, while the Ca2+-binding sites have been identified by cryo-EM studies, how Ca2+ and voltage activate TRPM4&5 channels remains unknown. Furthermore, while most known disease-causing TRPM4 mutations lead to a gain-of-function phenotype, no effective inhibitor for TRPM4&5 is currently available. Based on our preliminary functional data on TRPM4 Ca2+ and voltage activation, our discovery of novel TRPM4 mutations causing human skin disease, a new disease-causing mutant channel CRISPR mouse model exhibiting skin phenotypes, and our recent discovery of a novel TRPM4 inhibition process, we plan to use a multidisciplinary approach aiming at revealing the fundamental mechanisms of TRPM4&5 activation and inhibition.