title: Two-dimensional kinetics of inter-connexin interactions from single-molecule force spectroscopy.
abstract: Gap junction channels are intercellular channels that form by docking the extracellular loops of connexin protein subunits. While the structure and function of gap junctions as intercellular channels have been characterized using different techniques, the physics of the inter-connexin interaction remain unknown. Moreover, as far as we know, the capacity of gap junction channels to work as adhesion complexes supporting pulling forces has not yet been quantitatively addressed. We report the first quantitative characterization of the kinetics and binding strength of the interaction of a short peptide mimicking extracellular loop 2 of Cx26 with membrane-reconstituted Cx26, combining the imaging and force spectroscopy capabilities of atomic force microscopy. The fast dissociation rate inferred a dynamic bond, while the slow association rate reflected the reduced flexibility and small size of extracellular loops. Our results propose the gap junction channel as an adhesion complex that associates slowly and dissociates fast at low force but is able to support important pulling forces in its native, hexameric form.
authors.affiliation: Institut Curie, U1006 INSERM, 26 rue d'Ulm, 75005 Paris, France.
authors.forename: Felix
authors.initials: F
authors.lastname: Rico
authors.forename: Atsunori
authors.initials: A
authors.lastname: Oshima
authors.forename: Peter
authors.initials: P
authors.lastname: Hinterdorfer
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Fujiyoshi
authors.forename: Simon
authors.initials: S
authors.lastname: Scheuring
mesh_terms: D000072259:Connexin 26; D017630:Connexins / Q000737:chemistry* / Q000378:metabolism*; D017629:Gap Junctions / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D018625:Microscopy, Atomic Force / Q000379:methods*; D008958:Models, Molecular; D017433:Protein Structure, Secondary
chemical_list: D017630:Connexins; C000607042:GJB2 protein, human; D000072259:Connexin 26