The domain within your query sequence starts at position 510 and ends at position 886; the E-value for the REJ domain shown below is 1.8e-13.

HVAVPAEGTFLVTVHVRNAFSELSLDIGNITVTASSSLQELSGINAEAKSGHKQDMKVFT
EPELYVDPFTEVTLGWPDDDPGLNFHWSCGRCWAQWNACVGRQLLHTDQRLLVLHTFCLP
PLNSAVTLHLAILRGQELEKETEQCLYVSAPLNLGPQISCEKNCRPVKADQDVLLTVTVG
DETSVAVFSWYLDDTVPEEAEPLPAACRLRGFWPRSLTLLHSNSSVLLLNSSFLQTWGPV
IPIRVTALTSHAYGEDTYMISMLPRPEVPACTIDPEEGSVLTSFTVSCSTPATLGPVEYC
FCLPSGFCLHCGPEPALPAVYLPLGEEKDGFVLPVVISVTNRAGDIEQTQVAVKVGHSYT
GVEDVTFQEMVSERIAT

REJ

REJ
PFAM accession number:PF02010
Interpro abstract (IPR002859):

The REJ (Receptor for Egg Jelly) domain is found in PKD1 P98161 and the sperm receptor for egg jelly Q26627. The exact 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.

Sequence similarity between a region of the autosomal dominant polycystic kidney disease (ADPKD) protein, polycystin-1 and a sea urchin sperm glycoprotein involved in fertilization, the receptor for egg jelly (suREJ) has been known for some time. The suREJ protein binds the glycoprotein coat of the egg (egg jelly), triggering the acrosome reaction, which transforms the sperm into a fusogenic cell. The sequence similarity and expression pattern suggests that the predicted human PKDREJ protein is a mammalian equivalent of the suREJ protein and therefore may have a central role in human fertilization [(PUBMED:9949214)].

This is a PFAM domain. For full annotation and more information, please see the PFAM entry REJ