Gap Junction Protein Delta 4 (GJd4)

Connexins, such as GJD4, are involved in the formation of gap junctions, intercellular conduits that directly connect the cytoplasms of contacting cells. Each gap junction channel is formed by docking of 2 hemichannels, each of which contains 6 connexin subunits. By database analysis and PCR of human genomic DNA, Sohl et al. (2003) cloned GJD4, which they called CX40.1. CX40.1 shares 56% amino acid identity with its mouse ortholog, Cx39, with the differences primarily in the cytoplasmic loops and C termini. Northern blot analysis detected a 4.7-kb CX40.1 transcript in pancreas, kidney, skeletal muscle, liver, placenta, and heart. Cx39 was not expressed in any adult mouse tissues examined.