Desmocollins form a distinct subset of the cadherin family of cell adhesion molecules

Abstract

The desmosomal adhesive core is formed by four major components: desmoglein (Mr, 165,000), desmocollins I and II (Mr, 120,000 and 110,000, respectively), and a Mr 22,000 protein. Here, we report the cloning and sequencing of cDNAs encoding a bovine desmocollin. The open reading frame found in the longest cDNA, 5 kilobases, contains a region encoding a protein of 839 amino acids. The features of the deduced amino acid sequence imply that the mature 707-amino acid desmocollin is a type I transmembrane protein that is produced by proteolytic cleavage of an 810-amino acid precursor. The ectodomain of desmocollin contains repeats that show extensive sequence similarity to members of the cadherin family of calcium-dependent cell adhesion molecules. A comparison of the amino acid sequences of desmocollin, desmoglein, and the cadherins shows that although these intercellular junctional adhesion molecules share a consensus sequence in their adhesive domains that defines them as a family, several features, including the divergence in the sequence of their cytoplasmic tails, divide them into three distinct subtypes.