Mobility of Lower MA-Helices for Ion Conduction through Lateral Portals in 5-HT_3A Receptors.

ABSTRACT: The intracellular domain of the serotonin type 3A receptor, a pentameric ligand-gated ion channel, is crucial for regulating conductance. Ion permeation through the extracellular vestibule and the transmembrane channel is well understood, whereas the specific ion conduction pathway through the intracellular domain is less clear. The intracellular domain starts with a short loop after the third transmembrane segment, followed by a short α-helical segment, a large unstructured loop, and finally, the membrane-associated MA-helix that continues into the last transmembrane segment. The MA-helices from all five subunits form the extension of the transmembrane ion channel and shape what has been described as a "closed vestibule," with their lateral portals obstructed by loops and their cytosolic

SUBMITTER: Stuebler AG 

PROVIDER: S-EPMC7822733 | biostudies-literature | 2020 Dec

REPOSITORIES: biostudies-literature