Figure 3.

The distribution of gap junction proteins across Metazoa. Pannexins (innexins) and connexins are two unrelated families of proteins [91] with similar transmembrane topology, which illustrate unique examples of convergent evolution of electrical synapses. Note multiple examples of gene gains and losses across Metazoa. Y-axis indicates the presence and the number of genes encoding connexins or pannexins in selected reference species. The two representative three-dimensional structures are shown at the top of the figure using examples from humans (model of connexin 7jkc) and the ctenophore Pleurobrachia bachei (model of pannexin 6wbi), respectively. The three-dimensional reconstruction was performed using Phyre2 modelling [93].