The REJ (Receptor for Egg Jelly) domain is found in PKD1 Swiss:P98161, and the sperm receptor for egg jelly Swiss:Q26627. The function of this domain is unknown. The domain is 600 amino acids long so is probably composed of multiple structural domains. There are six completely conserved cysteine residues that may form disulphide bridges. This region contains tandem PKD-like domains.

1: The sea urchin sperm receptor for egg jelly is a modular protein with extensive homology to the human polycystic kidney disease protein, PKD1. Moy GW, Mendoza LM, Schulz JR, Swanson WJ, Glabe CG, Vacquier VD; J Cell Biol 1996;133:809-817. PMID:8666666

2: Identification of a human homologue of the sea urchin receptor for egg jelly: a polycystic kidney disease-like protein. Hughes J, Ward CJ, Aspinwall R, Butler R, Harris PC; Hum Mol Genet 1999;8:543-549. PMID:9949214