ID   U21_HHV6U               Reviewed;         433 AA.
AC   Q69556; Q69045;
DT   01-MAR-2004, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1996, sequence version 1.
DT   03-AUG-2022, entry version 80.
DE   RecName: Full=Glycoprotein U21;
GN   Name=U21; Synonyms=EJLF2;
OS   Human herpesvirus 6A (strain Uganda-1102) (HHV-6 variant A) (Human B
OS   lymphotropic virus).
OC   Viruses; Duplodnaviria; Heunggongvirae; Peploviricota; Herviviricetes;
OC   Herpesvirales; Herpesviridae; Betaherpesvirinae; Roseolovirus.
OX   NCBI_TaxID=10370;
OH   NCBI_TaxID=9606; Homo sapiens (Human).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=8289364; DOI=10.1128/jvi.68.2.597-610.1994;
RA   Nicholas J., Martin M.E.D.;
RT   "Nucleotide sequence analysis of a 38.5-kilobase-pair region of the genome
RT   of human herpesvirus 6 encoding human cytomegalovirus immediate-early gene
RT   homologs and transactivating functions.";
RL   J. Virol. 68:597-610(1994).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RX   PubMed=7747482; DOI=10.1006/viro.1995.1228;
RA   Gompels U.A., Nicholas J., Lawrence G.L., Jones M., Thomson B.J.,
RA   Martin M.E.D., Efstathiou S., Craxton M.A., Macaulay H.A.;
RT   "The DNA sequence of human herpesvirus-6: structure, coding content, and
RT   genome evolution.";
RL   Virology 209:29-51(1995).
CC   -!- FUNCTION: Binds to MHC class I molecules in the endoplasmic reticulum
CC       and targets them from the Golgi directly to the lysosomes. Once in the
CC       lysosomes both proteins are degraded. In consequence, surface class I
CC       molecules are down-regulated and infected cells are masked for immune
CC       recognition by cytotoxic T lymphocytes (By similarity). {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Host endoplasmic reticulum membrane
CC       {ECO:0000250}; Single-pass type I membrane protein {ECO:0000250}.
CC   -!- DOMAIN: The ER-lumenal domain associates with class I MHC molecules and
CC       is responsible for lysosomal sorting. {ECO:0000250}.
CC   -!- SIMILARITY: Belongs to the herpesviruses U21 family. {ECO:0000305}.
CC   -!- SEQUENCE CAUTION:
CC       Sequence=AAA16728.1; Type=Erroneous initiation; Evidence={ECO:0000305};
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DR   EMBL; L25528; AAA16728.1; ALT_INIT; Genomic_DNA.
DR   EMBL; X83413; CAA58401.1; -; Genomic_DNA.
DR   PIR; T09315; T09315.
DR   RefSeq; NP_042914.1; NC_001664.2.
DR   PRIDE; Q69556; -.
DR   DNASU; 1487967; -.
DR   GeneID; 1487967; -.
DR   KEGG; vg:1487967; -.
DR   Proteomes; UP000009295; Genome.
DR   GO; GO:0044167; C:host cell endoplasmic reticulum membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
PE   3: Inferred from homology;
KW   Glycoprotein; Host endoplasmic reticulum; Host membrane;
KW   Host-virus interaction; Membrane; Reference proteome; Transmembrane;
KW   Transmembrane helix; Viral immunoevasion.
FT   CHAIN           1..433
FT                   /note="Glycoprotein U21"
FT                   /id="PRO_0000116355"
FT   TOPO_DOM        1..364
FT                   /note="Lumenal"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        365..385
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TOPO_DOM        386..433
FT                   /note="Cytoplasmic"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        164
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
SQ   SEQUENCE   433 AA;  49395 MW;  054834689F77A436 CRC64;
     MMICLVFLCV LTLARGEIYP PICPAPGVGN DEAVRAGELL LEISAYRNQR SGRVELWGSA
     AVNNQVFYGG MENSQIDYDF GKFLVFRCFQ VFNNVHKLLF NTVSSATMHL ARKRVQKCGH
     GKMTFISIQV QCSVNKKSIR LSRMSEASLK KQVLRVAFFL DRNNNSWIAD KNFQGEDRTM
     LRLWNELSTY QQYLISSCNN DVKILSELYG EFRQIALPYD EKLNLNFMPV IRSSSERLFR
     ADDLKCSFSR WLGAEGEFAV CEYSGWGVSR LGKIEIFAEK PLTFDMAWKT VKMRSSGAYT
     SLFRDDVTWG LIPLDKWVGD KYFCMCTNKE SGDNVIVTLP EKNVEKSIQI YDEGSAMLSF
     AEMTSIILNL MFMGAVAVSV GILGISCFVG LKEIIYFIFV SVDYMWPFCD TLLTTAVNCF
     FKGRTFLRRE LKI