Protein Domain : Gap junction alpha-3 protein (Cx46) IPR002262

Type	Family
Description	Gap junction alpha-3 protein (also called connexin46, or Cx46) is a connexin of ~415 amino acid residues. The bovine form is slightly shorter (401residues) and is hence known as Cx44, having a molecular mass of ~44 kD. Cx46 (together with Cx50) is a connexin isoform expressed in the lens fibresof the eye. Here, gap junctions join the cells into a functional syncytium, and also couple the fibres to the epithelial cells on the anterior surfaceof the lens. The lens fibres depend on this epithelium for their metabolic support, since they lose their intra-cellular organelles, and accumulatehigh concentrations of crystallins, in order to produce their optical transparency. Genetically-engineered mice deficient in Cx46 demonstrate theimportance of Cx46 in forming lens fibre gap junctions; these mice develop normal lenses, but subsequently develop early onset senile-type cataractsthat resemble human nuclear cataracts. Aberrant proteolysis of crystallin proteins was observed in the lenses of Cx46-null mice [ ]. A Cx46 mutant in a highly conserved threonine has been linked toautosomal dominant cataracts. This mutation causes loss of gap junction function and alters hemi-channel gating [ ].
Short Name	Connexin46