Gap junctions are comprised of proteinaceous, plasma membrane channels that link the
interiors of adjacent cells and permit cells to directly exchange small (< 1,000 Daltons)
molecules and ions. This exchange, termed gap junctional intercellular communication
(GJIC), appears to be involved in growth regulation. Growth controlling factors may pass
between cells through the junctions. The loss of gap junctions or impairment of their
permeability has been observed in many neoplastic cells and cells treated with growth …

Gap junctions consist of clusters of channels embedded in the plasma membranes of
adjacent cells that directly link the two cell interiors and that permit the cell-to-cell exchange
of small (< 1,000 Da) cytoplasmic molecules and ions. This transfer has been called gap
junctional intercellular communication (GJIC). The proteins forming the channels are known
as connexins. Many connexin genes have been cloned, but the regulation of their
expression is poorly understood. The proposed roles of GJIC include tissue homeostasis …