The cell-cell channel in the control of growth.

Several lines of evidence indicate that the cell-cell channels in gap junction are conduits for growth-regulating signals. Experimental upregulation of the channels by retinoids causes inhibition of cellular growth and, conversely, their downregulation by oncogenes, e.g. activated src, stimulates growth. In either direction, the extent of growth correlates tightly with the degree of communication. Cogent evidence of the channel's function in growth regulation is now on hand: incorporation of a channel-protein gene into the genome of a transformed communication-deficient cell line normalizes communication and growth. The current data conform to a model of growth control with discrete regulatory centers.