Polyamines regulate gap junction communication in connexin 43-expressing cells

The control of cell–cell communication through gap junctions is thought to be crucial in normal tissue function and during various stages of tumorigenesis. However, few natural regulators of gap junctions have been found. We show here that increasing the activity of ornithine decarboxylase, or adding polyamines to the outside of cells, increases the level of gap junction communication between various epithelial cells. Conversely, reduction of ornithine decarboxylase activity decreases the level of gap junction communication. This regulation is dependent upon the expression of connexin 43 (Cx43 or Cxa1), which is a major connexin expressed in many different cell types, and involves an increase in Cx43 and its cellular re-distribution.