Activation and Inhibition Mechanisms of Calcium-Activated Nonselective Cation Channels

项目摘要 Ca 2+激活的非选择性阳离子（CAN）通道是少数几个离子通道， 细胞内Ca 2+信号传导转化为膜电位变化，与大多数离子相反， 直接或间接利用膜电位调节细胞内Ca 2+的通道 信号这种独特的性质使CAN通道在许多组织中发挥关键作用， 机关虽然CAN通道的存在已经知道了几十年，但最近的证据表明， 已经确定单价阳离子可渗透的TRPM 4和TRPM 5是长期以来寻求的 CAN通道事实上，许多TRPM 4突变与严重的人类疾病有关， 例如，在一个实施例中，心脏传导阻滞、Bragada综合征、PSEK（一种皮肤病）。尽管他们 功能的重要性，很少有人知道的分子机制，管理TRPM 4和5 渠道活动。Ca ~（2+）是它们唯一已知的生理激活剂， 电位也调节通道活性，但仅在Ca 2+存在下。然而，虽然 Ca 2+结合位点已通过冷冻EM研究确定，Ca 2+和电压如何激活 TRPM4&5通道仍然未知。此外，虽然大多数已知的致病 TRPM 4突变导致功能获得性表型，没有有效的TRPM 4和5抑制剂。 目前可用。基于我们对TRPM 4 Ca 2+和电压的初步功能数据， 激活，我们发现新的TRPM 4突变导致人类皮肤病，一个新的 显示皮肤表型的致病突变通道CRISPR小鼠模型， 最近发现了一种新的TRPM 4抑制过程，我们计划使用多学科 旨在揭示TRPM 4和5激活的基本机制， 抑制作用

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.