Cysteine-rich domain of carboxypeptidase Z, a member of the carboxypeptidase E family.
The cysteine-rich-domain (CRD) is an essential part of carboxypeptidase Z, a member of the carboxypeptidase E family of metallocarboxypeptidases. This is a group of Zn-dependent enzymes implicated in the intra- and extracellular processing of proteins. Carboxypeptidase Z removes C-terminal basic amino acid residues from its substrates, particularly arginine. The CRD acts as a ligand-binding domain for Wnts involved in developmental processes. CPZ binds and may process Wnt-4, CPZ has also been found to enhance the induction of the homeobox gene Cdx1. During vertebrate embryogenesis, the CRD of CPZ upregulates Pax3, a Wnt reporter gene essential for patterning of somites and limb development.