The domain within your query sequence starts at position 273 and ends at position 498; the E-value for the Nicastrin domain shown below is 1.6e-94.

RVVVAATRLDSRSFFWNVAPGAESAVASFVTQLAAAEALHKAPDVTTLSRNVMFVFFQGE
TFDYIGSSRMVYDMENGKFPVRLENIDSFVELGQVALRTSLDLWMHTDPMSQKNESVKNQ
VEDLLATLEKSGAGVPEVVLRRLAQSQALPPSSLQRFLRARNISGVVLADHSGSFHNRYY
QSIYDTAENINVTYPEWQSPEEDLNFVTDTAKALANVATVLARALY

Nicastrin

Nicastrin
PFAM accession number:PF05450
Interpro abstract (IPR008710): Nicastrin and presenilin are two major components of the gamma-secretase complex, which executes the intramembrane proteolysis of type I integral membrane proteins such as the amyloid precursor protein (APP) and Notch. Nicastrin is synthesised in fibroblasts and neurons as an endoglycosidase-H-sensitive glycosylated precursor protein (immature nicastrin) and is then modified by complex glycosylation in the Golgi apparatus and by sialylation in the trans-Golgi network (mature nicastrin) [(PUBMED:12584255)].
GO process:protein processing (GO:0016485)
GO component:integral component of membrane (GO:0016021)

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