title: Different domains are critical for oligomerization compatibility of different connexins.
abstract: Oligomerization of connexins is a critical step in gap junction channel formation. Some members of the connexin family can oligomerize with other members and form functional heteromeric hemichannels [e.g. Cx43 (connexin 43) and Cx45], but others are incompatible (e.g. Cx43 and Cx26). To find connexin domains important for oligomerization, we constructed chimaeras between Cx43 and Cx26 and studied their ability to oligomerize with wild-type Cx43, Cx45 or Cx26. HeLa cells co-expressing Cx43, Cx45 or Cx26 and individual chimaeric constructs were analysed for interactions between the chimaeras and the wild-type connexins using cell biological (subcellular localization by immunofluorescence), functional (intercellular diffusion of microinjected Lucifer yellow) and biochemical (sedimentation velocity through sucrose gradients) assays. All of the chimaeras containing the third transmembrane domain of Cx43 interacted with wild-type Cx43 on the basis of co-localization, dominant-negative inhibition of intercellular communication, and altered sedimentation velocity. The same chimaeras also interacted with co-expressed Cx45. In contrast, immunofluorescence and intracellular diffusion of tracer suggested that other domains influenced oligomerization compatibility when chimaeras were co-expressed with Cx26. Taken together, these results suggest that amino acids in the third transmembrane domain are critical for oligomerization with Cx43 and Cx45. However, motifs in different domains may determine oligomerization compatibility in members of different connexin subfamilies.
authors.affiliation: Centro Interdisciplinario de Neurociencias de Valparaíso, Departamento de Neurociencias, Universidad de Vaparaíso, Valparaíso 2360102, Chile. agustin.martinez@uv.cl
authors.forename: Agustín D
authors.initials: AD
authors.lastname: Martínez
authors.forename: Jaime
authors.initials: J
authors.lastname: Maripillán
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Acuña
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Minogue
authors.forename: Viviana M
authors.initials: VM
authors.lastname: Berthoud
authors.forename: Eric C
authors.initials: EC
authors.lastname: Beyer
mesh_terms: D000818:Animals; D000072259:Connexin 26; D018031:Connexin 43 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017630:Connexins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D006367:HeLa Cells; D006801:Humans; D017434:Protein Structure, Tertiary; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
chemical_list: D018031:Connexin 43; D017630:Connexins; C000607042:GJB2 protein, human; C000607044:Gjb2 protein, rat; D011993:Recombinant Fusion Proteins; D000072259:Connexin 26