Characterization of the association of connexins and ZO-1 in the lens.
ZO-1 (Zona Occludens protein 1) has previously been shown to bind Cx43alpha1. This interaction involves the most C-terminal residues of Cx43alpha1 and the second PDZ-domain of ZO-1. The biological significance of this interaction is not well understood. The similarity of the C-terminal residues of the lens connexins Cx46alpha3 and Cx50alpha8 to Cx43alpha1 prompted us to examine if ZO-1 is expressed in the lens, and if ZO-1 interacts with lens connexins. A high level of ZO-1 expression was detected in the mouse lens. Lens connexins were shown to co-immunoprecipitate with ZO-1, and the interaction was found to involve similar domains as those previously demonstrated for the Cx43alpha1/ZO-1 interaction (Nielsen et al. manuscript in preparation). Futhermore, transient expression of Cx46alpha3 and Cx50alpha8 in cell culture showed colocalization of gap junction plaques with ZO-1, further suggesting that lens connexins interact with ZO-1. Sequence comparison suggests that a large number of connexins of the alpha subclass may interact with ZO-1. Using the lens as a system to study connexin/ZO-1 interactions may further our understanding of their biological significance in the lens, as well as in other organs.
Nielsen
P A
PA
Department of Cell Biology, The Scripps Research Institute, La Jolla, CA 92037, USA. nalin@uic.edu
Baruch
A
A
Giepmans
B N
BN
Kumar
N M
NM
D000818:Animals; D002460:Cell Line; D017630:Connexins / Q000378:metabolism*; D030561:Databases, Nucleic Acid; D017629:Gap Junctions / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D007908:Lens, Crystalline / Q000737:chemistry* / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D010750:Phosphoproteins / Q000378:metabolism*; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D016415:Sequence Alignment; D062826:Zonula Occludens-1 Protein
D017630:Connexins; D008565:Membrane Proteins; D010750:Phosphoproteins; D011993:Recombinant Fusion Proteins; C569042:TJP1 protein, human; C569043:Tjp1 protein, mouse; D062826:Zonula Occludens-1 Protein