The domain within your query sequence starts at position 10 and ends at position 393; the E-value for the PIG-U domain shown below is 1.7e-116.

VVAVTVRAALFRSSLAEFISERVEVVSPLSSWKRVVEGLALLDLGVSPYSGAVFHETPLI
IYLFHFLIDYAELVFMITDALTAIALYFAIQDFNKVVFKKQKLLLELDQYAPDVAELIRT
PMEMRYIPLKVALYLLNPYTILSCVAKSTCAINNTLIAFFILTTIKGSVFLSAVFLALAT
YQSLYPVTLFAPGLLYLLQRQYIPVKVKSKAFWIFSWEYAMMYTGSLVVIVCLSFFLLSS
WDFIPAVYGFILSVPDLTPNIGLFWYFFAEMFEHFSLFFVCVFQINVFFYTVPLAIKLKE
HPIFFMFIQIAIISIFKSYPTVGDVALYMAFFPVWNHLYRFLRNIFVLTCIIIVCSLLFP
VLWHLWIYAGSANSNFFYAITLTF

PIG-U

PIG-U
PFAM accession number:PF06728
Interpro abstract (IPR009600):

Many eukaryotic proteins are anchored to the cell surface via glycosylphosphatidylinositol (GPI), which is posttranslationally attached to the C terminus by GPI transamidase. The mammalian GPI transamidase is a complex of at least four subunits, GPI8, GAA1, PIG-S, and PIG-T. PIG-U is thought to represent a fifth subunit in this complex and may be involved in the recognition of either the GPI attachment signal or the lipid portion of GPI [(PUBMED:12802054)].

GO process:attachment of GPI anchor to protein (GO:0016255)
GO component:GPI-anchor transamidase complex (GO:0042765), integral component of membrane (GO:0016021)

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