title: Lens connexins alpha3Cx46 and alpha8Cx50 interact with zonula occludens protein-1 (ZO-1).
abstract: Connexin alpha1Cx43 has previously been shown to bind to the PDZ domain-containing protein ZO-1. The similarity of the carboxyl termini of this connexin and the lens fiber connexins alpha3Cx46 and alpha8Cx50 suggested that these connexins may also interact with ZO-1. ZO-1 was shown to be highly expressed in mouse lenses. Colocalization of ZO-1 with alpha3Cx46 and alpha8Cx50 connexins in fiber cells was demonstrated by immunofluorescence and by fracture-labeling electron microscopy but showed regional variations throughout the lens. ZO-1 was found to coimmunoprecipitate with alpha3Cx46 and alpha8Cx50, and pull-down experiments showed that the second PDZ domain of ZO-1 was involved in this interaction. Transiently expressed alpha3Cx46 and alpha8Cx50 connexins lacking the COOH-terminal residues did not bind to the second PDZ domain but still formed structures resembling gap junctions by immunofluorescence. These results indicate that ZO-1 interacts with lens fiber connexins alpha3Cx46 and alpha8Cx50 in a manner similar to that previously described for alpha1Cx43. The spatial variation in the interaction of ZO-1 with lens gap junctions is intriguing and is suggestive of multiple dynamic roles for this association.
authors.affiliation: Department of Cell Biology, The Scripps Research Institute, La Jolla, California 92037, USA.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Nielsen
authors.forename: Amos
authors.initials: A
authors.lastname: Baruch
authors.forename: Valery I
authors.initials: VI
authors.lastname: Shestopalov
authors.forename: Ben N G
authors.initials: BN
authors.lastname: Giepmans
authors.forename: Irene
authors.initials: I
authors.lastname: Dunia
authors.forename: E Lucio
authors.initials: EL
authors.lastname: Benedetti
authors.forename: Nalin M
authors.initials: NM
authors.lastname: Kumar
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D017630:Connexins / Q000378:metabolism*; D007908:Lens, Crystalline / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D011233:Precipitin Tests; D017434:Protein Structure, Tertiary; D062826:Zonula Occludens-1 Protein
chemical_list: D017630:Connexins; D008565:Membrane Proteins; D010750:Phosphoproteins; C569043:Tjp1 protein, mouse; D062826:Zonula Occludens-1 Protein