Gap junction protein, alpha 1 is a member of the connexin gene family and a component of gap junctions. Gap junctions are composed of arrays of intercellular channels and provide a route for the diffusion of materials of low molecular weight from cell to cell. Connexin 43 is the major protein of gap junctions in the heart, and gap junctions are thought to have a crucial role in the synchronized contraction of the heart and in embryonic development. Connexin 43 is targeted by several protein kinases that regulate myocardial cell-cell coupling. A related intron-less connexin 43 pseudogene, GJA1P, has been mapped to chromosome 5.