Protocadherin-8: Proteins and Enzymes

Protocadherin 8 (PCDH-8, Arcadlin) is a 110-115 kDa group F member of the protocadherin family of molecules. It is expressed in breast epithelium, the synaptic membranes of neurons, and presumably forms Ca⁺⁺-dependent homophilic complexes. In breast, it is believed to contribute to a stable epithelial architecture, while in brain, it impacts LTP. Mature human PCDH-8 is a type I transmembrane protein that is 1041 amino acids (aa) in length. It contains a 720aa extracellular domain (ECD) (aa 30-749) plus a 300 aa cytoplasmic region. There are six cadherin domains in the ECD (aa 30-723). Multiple splice variants exist. Two show deletions of aa 134-607 and 781-877, respectively, while a third shows a six aa substitution for aa 365-527. Over aa 30-689, human PCDH-8 shares 93% aa identity with mouse PCDH-8.