Learning the language of cell-cell communication through connexin channels

Abstract

A report on the Ninth International Gap Junction Conference, Honolulu, USA, 4-9 August 2001.

Figure 1

A molecular phylogenetic tree for human connexin protein sequences (HCx) and rat connexin 33 (rCx33). The divergent sequence portions (the intracellular loop and the carboxy-terminal domain) were removed from the multiple alignments. The distance matrices were then analyzed by the neighbor-joining method of Saitou and Nei (Mol Biol Evol 1987, 4:406-425), producing an unrooted molecular phylogenetic tree. The connexin family can be broadly separated into three main subgroups, the historical α (green) and β (blue) and a more divergent non-α non-β branch. A sequence divergence of 10% is indicated by the scale bar. The tree is provided courtesy of Daniele Condorelli (University of Catania, Italy).

Figure 2

The mammalian retina uses electrical synapses in the vertical pathway from rod photoreceptors to ON-ganglion cells. In scotopic view, rod bipolar cells send signals to rod bipolar cells to excite AII amacrine cells through conventional synapses (green arrows). The AII cell forms electrical synapses (blue jagged line) with ON-cone bipolar cells, thus parasitizing the cone pathway. This pathway is lost in Cx36 knockout animals. Red arrows denote chemical inhibitory synapses. The diagram is modified from Strettoi, Dacheux and Raviola (J Comp Neurol 1994, 347:139-149).