Reticulocalbin 3 (RCN3) belongs to the CREC (cab45/reticulocalbin/ ERC45/calumenin) family. RCN3 contains 5 Arg-Xaa-Xaa-Arg motifs, which function as target sequences of SPCs (subtilisin-like proprotein convertases), which is a family of serine endoproteases that proteolytically activate proproteins. The synthesis of PACE4 is induced by association and coexpression with RCN3.