Gap junction alpha-3 protein (Cx46) (IPR002262)

Short name: Connexin46

Family relationships

  • Connexin (IPR000500)
    • Gap junction alpha-3 protein (Cx46) (IPR002262)


Gap junction alpha-3 protein (also called connexin46, or Cx46) is a connexin of ~415 amino acid residues. The bovine form is slightly shorter (401 residues) 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 fibres of the eye. Here, gap junctions join the cells into a functional syncytium, and also couple the fibres to the epithelial cells on the anterior surface of the lens. The lens fibres depend on this epithelium for their metabolic support, since they lose their intra-cellular organelles, and accumulate high concentrations of crystallins, in order to produce their optical transparency. Genetically-engineered mice deficient in Cx46 demonstrate the importance of Cx46 in forming lens fibre gap junctions; these mice develop normal lenses, but subsequently develop early onset senile-type cataracts that resemble human nuclear cataracts. Aberrant proteolysis of crystallin proteins has been observed in the lenses of Cx46-null mice.

GO terms

Biological Process

GO:0006810 transport

Molecular Function

GO:0005243 gap junction channel activity

Cellular Component

GO:0005921 gap junction

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.