Structural basis for the selective permeability of channels made of communicating junction proteins

► Multiple connexin regions define permeability and selectivity of gap junctions. ► Gating, electrostatic interactions and phosphorylation modify channel function. ► Junctional molecular and ionic permeability may change in non-parallel fashion. ► Multiple mechanisms of channel gating have been proposed. ► Naturally existing junctional permeants are not broadly known.