9QNT

Connexin-32 (Cx32) in MSP2N2 nanodiscs with liver polar lipids

Summary for 9QNT

• Entry DOI: 10.2210/pdb9qnt/pdb
• EMDB information: 53240 53244 53245 53250
• Descriptor: Gap junction beta-1 protein,Green fluorescent protein, (2S)-3-(hexadecanoyloxy)-2-[(9Z)-octadec-9-enoyloxy]propyl 2-(trimethylammonio)ethyl phosphate, CHOLESTEROL (3 entities in total)
• Functional Keywords: gap junction channel, membrane transport, lipids, membrane protein
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 12
• Total formula weight: 773689.82

Authors

Korkhov, V.M.,Lavriha, P. (deposition date: 2025-03-25, release date: 2025-12-17)

Primary citation

Lavriha, P.,Fluri, C.,Hernandez Gonzalez, J.E.,Korkhov, V.M.
Lipid dependence of connexin-32 gap junction channel conformations.
Nat Commun, 2025

PubMed Abstract: Connexin-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.

PubMed: 41350533
DOI: 10.1038/s41467-025-67004-z

Experimental method

ELECTRON MICROSCOPY (3.29 Å)