Fig. 1
From: Bridging the gap to therapeutic strategies based on connexin/pannexin biology
Figure contributed by Dr. M. Le Vasseur, University of British Columbia, Canada
Connexin and pannexin topology. Connexin and pannexin share a common structural topology despite the absence of sequence homology. Both are transmembrane proteins with four transmembrane domains, two extracellular loops, one cytoplasmic loop, and cytoplasmic N– and C–terminal domains (a, c). Connexin and pannexin monomers both oligomerize to form a functional ‘connexon’ and ‘pannexon’ channel, respectively. However, only connexin channels can assemble into a gap junction that allows intercellular communication. Pannexin is glycosylated and large glycan residues prevent the docking of pannexin channels from adjacent cells (b, d). The amino acid sequences in a and c represent human Cx43 and Panx1 respectively. PTMs post-translational modifications.