| Primary Identifier | IPR002262 | Type | Family |
| Short Name | Connexin46 |
| description | Gap junction alpha-3 protein (also called connexin46, or Cx46) is a connexinof ~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 metabolicsupport, since they lose their intra-cellular organelles, and accumulatehigh concentrations of crystallins, in order to produce their opticaltransparency. Genetically-engineered mice deficient in Cx46 demonstrate theimportance of Cx46 in forming lens fibre gap junctions; these mice developnormal 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 []. |
