National Institutes of Health/National Heart, Lung, and Blood Institute (NIH/NHLBI)
R56HL144929
米国
National Institutes of Health/National Institute of Neurological Disorders and Stroke (NIH/NINDS)
R01NS111031
米国
American Heart Association
20POST35120556
米国
引用
ジャーナル: Nature / 年: 2020 タイトル: Structures of human pannexin 1 reveal ion pathways and mechanism of gating. 著者: Zheng Ruan / Ian J Orozco / Juan Du / Wei Lü / 要旨: Pannexin 1 (PANX1) is an ATP-permeable channel with critical roles in a variety of physiological functions such as blood pressure regulation, apoptotic cell clearance and human oocyte development. ...Pannexin 1 (PANX1) is an ATP-permeable channel with critical roles in a variety of physiological functions such as blood pressure regulation, apoptotic cell clearance and human oocyte development. Here we present several structures of human PANX1 in a heptameric assembly at resolutions of up to 2.8 angström, including an apo state, a caspase-7-cleaved state and a carbenoxolone-bound state. We reveal a gating mechanism that involves two ion-conducting pathways. Under normal cellular conditions, the intracellular entry of the wide main pore is physically plugged by the C-terminal tail. Small anions are conducted through narrow tunnels in the intracellular domain. These tunnels connect to the main pore and are gated by a long linker between the N-terminal helix and the first transmembrane helix. During apoptosis, the C-terminal tail is cleaved by caspase, allowing the release of ATP through the main pore. We identified a carbenoxolone-binding site embraced by W74 in the extracellular entrance and a role for carbenoxolone as a channel blocker. We identified a gap-junction-like structure using a glycosylation-deficient mutant, N255A. Our studies provide a solid foundation for understanding the molecular mechanisms underlying the channel gating and inhibition of PANX1 and related large-pore channels.