Compact and scattered gap junctions in diffusion mediated cell-cell communication

Gap junctions have been thought of as prime sites for the passive communication of small molecules between two adjacent cells. The sizes of a gap junction plaque may range from a few junctional particles to several thousands particles on the interface of two cells, with little being known about the relative contribution of different patterns of junctional plaques on diffusion mediated cell-cell communication. In this paper, by constructing a simple cubic lattice model of a two-cell system, the effects on communication efficiency of two extreme distribution patterns of individual junctional particles are investigated. This model indicates that scattered gap junctions are an order of magnitude higher in communication efficiency than compact junctional plaques of equal number of total junctional particles. Thus, it is possible that modulation of cell-cell communication may rely on the interconversion of these two states with compact plaques existing as an inactive communication form. Any correlation of gap junctional membrane with cell-cell communication should therefore also take into account its configuration. It is possible that an increase in number and area of tightly packed gap junctional plaques may actually decrease, instead of increase, cell-cell communication.