9qnd
From Proteopedia
Connexin-32 (Cx32) W3S mutant gap junction channel in POPC-containing MSP2N2 nanodiscs
Structural highlights
DiseaseCXB1_HUMAN X-linked Charcot-Marie-Tooth disease type 1;X-linked progressive cerebellar ataxia. The disease is caused by mutations affecting the gene represented in this entry. The gene represented in this entry may act as a disease modifier. FunctionCXB1_HUMAN One gap junction consists of a cluster of closely packed pairs of transmembrane channels, the connexons, through which materials of low MW diffuse from one cell to a neighboring cell. Publication Abstract from PubMedConnexin-32 (Cx32) gap junction channels (GJCs) mediate intercellular coupling in various tissues, including myelinating Schwann cells. Mutations in Cx32, such as W3S, are associated with X-linked Charcot-Marie-Tooth (CMT1X) disease. Lipids regulate Cx32 GJC permeation, although the regulatory mechanism is unclear. Here, we determine the cryo-EM structures of Cx32 GJCs reconstituted in nanodiscs, revealing that phospholipids block the Cx32 GJC pore by binding to the site formed by N-terminal gating helices. The phospholipid-bound state is contingent on the presence of a sterol molecule in a hydrophobic pocket formed by the N-terminus: the N-terminal helix of Cx32 fails to sustain a phospholipid binding site in the absence of cholesterol hemisuccinate. The CMT1X-linked W3S mutant which has an impaired sterol binding site adopts a conformation of the N-terminus incompatible with phospholipid binding. Our results indicate that different lipid species control connexin channel gating directly by influencing the conformation of the N-terminal gating helix. Lipid dependence of connexin-32 gap junction channel conformations.,Lavriha P, Fluri C, Hernandez Gonzalez JE, Korkhov VM Nat Commun. 2025 Dec 5. doi: 10.1038/s41467-025-67004-z. PMID:41350533[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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