7mbu

Cryo-EM structure of zebrafish TRPM5 E337A mutant in the presence of 5 mM calcium (high calcium occupancy in the transmembrane domain)

spinqualitylabelsall models 7mbu Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy Ligands: CA, NAG, YUV, YUY Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed The Ca(2+)-activated TRPM5 channel plays essential roles in taste perception and insulin secretion. However, the mechanism by which Ca(2+) regulates TRPM5 activity remains elusive. We report cryo-EM structures of the zebrafish TRPM5 in an apo closed state, a Ca(2+)-bound open state, and an antagonist-bound inhibited state. We define two novel ligand binding sites: a Ca(2+) site (CaICD) in the intracellular domain and an antagonist site in the transmembrane domain (TMD). The CaICD site is unique to TRPM5 and has two roles: modulating the voltage dependence and promoting Ca(2+) binding to the CaTMD site, which is conserved throughout TRPM channels. Conformational changes initialized from both Ca(2+) sites cooperatively open the ion-conducting pore. The antagonist NDNA wedges into the space between the S1-S4 domain and pore domain, stabilizing the transmembrane domain in an apo-like closed state. Our results lay the foundation for understanding the voltage-dependent TRPM channels and developing new therapeutic agents. Structures of the TRPM5 channel elucidate mechanisms of activation and inhibition.,Ruan Z, Haley E, Orozco IJ, Sabat M, Myers R, Roth R, Du J, Lu W Nat Struct Mol Biol. 2021 Jun 24. pii: 10.1038/s41594-021-00607-4. doi:, 10.1038/s41594-021-00607-4. PMID:34168372 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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