Reviewed, UniProtKB/Swiss-Prot P55808 (XG_HUMAN)

Names and origin

Protein names

Recommended name:
    Glycoprotein Xg
Alternative name(s):
    Protein PBDX

Gene names

Name:	XG
Synonyms:	PBDX

Organism

Homo sapiens (Human)

Taxonomic identifier

9606 [NCBI]

Taxonomic lineage

Eukaryota › Metazoa › Chordata › Craniata › Vertebrata › Euteleostomi › Mammalia › Eutheria › Euarchontoglires › Primates › Haplorrhini › Catarrhini › Hominidae › Homo

Protein attributes

Sequence length	180 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is further processed into a mature form.
Protein existence	Evidence at transcript level.

General annotation (Comments)

Subcellular location	Membrane; Single-pass type I membrane protein Potential.
Post-translational modification	O-glycosylated Probable.
Polymorphism	XG is responsible for the Xg blood group system.
Miscellaneous	The gene encoding for this protein is located in the pseudoautosomal region 1 (PAR1) of X and Y chromosomes.
Sequence similarities	Belongs to the CD99 family.
Caution	Ref.3 sequence incorrectly indicated as originating from mouse.

Ontologies

Keywords
Cellular component	Membrane
Coding sequence diversity	Alternative splicing Polymorphism
Domain	Signal Transmembrane
Molecular function	Blood group antigen
PTM	Glycoprotein
Gene Ontology (GO)
Cellular component	integral to membrane Inferred from electronic annotation. Source: UniProtKB-KW
Complete GO annotation...

Alternative products

This entry describes 3 isoforms produced by alternative splicing. [Align] [Select]

Isoform 1 (identifier: P55808-1)

This isoform has been chosen as the 'canonical' sequence. All positional information in this entry refers to it. This is also the sequence that appears in the downloadable versions of the entry.

Isoform 2 (identifier: P55808-2)

The sequence of this isoform differs from the canonical sequence as follows:
     85-85: G → GS

Note: No experimental confirmation available.

Isoform 3 (identifier: P55808-3)

The sequence of this isoform differs from the canonical sequence as follows:
     125-125: G → GRGGYRPNSRYGNTYG

Note: No experimental confirmation available.

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Signal peptide	1 – 21	21	Potential
	Chain	22 – 180	159	Glycoprotein Xg		PRO_0000022693
Regions
	Topological domain	22 – 142	121	Extracellular Potential
	Transmembrane	143 – 163	21	Potential
	Topological domain	164 – 180	17	Cytoplasmic Potential
Natural variations
	Alternative sequence	85	1	G → GS in isoform 2.		VSP_037319
	Alternative sequence	125	1	G → GRGGYRPNSRYGNTYG in isoform 3.		VSP_037320
	Natural variant	60	1	D → N: dbSNP rs5939319. Ref.4		VAR_054063

Sequences

	Sequence		Length	Mass (Da)
	Isoform 1 [UniParc]. Last modified November 1, 1997. Version 1. Checksum: DADAA9E6859C4530	FASTA	180	19,723
	10 20 30 40 50 60 MESWWGLPCL AFLCFLMHAR GQRDFDLADA LDDPEPTKKP NSDIYPKPKP PYYPQPENPD 70 80 90 100 110 120 SGGNIYPRPK PRPQPQPGNS GNSGGYFNDV DRDDGRYPPR PRPRPPAGGG GGGYSSYGNS 130 140 150 160 170 180 DNTHGGDHHS TYGNPEGNMV AKIVSPIVSV VVVTLLGAAA SYFKLNNRRN CFRTHEPENV
	Isoform 2. Checksum: 8B4531340686355C	FASTA	181	19,810
	10 20 30 40 50 60 MESWWGLPCL AFLCFLMHAR GQRDFDLADA LDDPEPTKKP NSDIYPKPKP PYYPQPENPD 70 80 90 100 110 120 SGGNIYPRPK PRPQPQPGNS GNSGGSYFND VDRDDGRYPP RPRPRPPAGG GGGGYSSYGN 130 140 150 160 170 180 SDNTHGGDHH STYGNPEGNM VAKIVSPIVS VVVVTLLGAA ASYFKLNNRR NCFRTHEPEN V
	Isoform 3. Checksum: A8738A12E7AEB8DF	FASTA	195	21,423
	10 20 30 40 50 60 MESWWGLPCL AFLCFLMHAR GQRDFDLADA LDDPEPTKKP NSDIYPKPKP PYYPQPENPD 70 80 90 100 110 120 SGGNIYPRPK PRPQPQPGNS GNSGGYFNDV DRDDGRYPPR PRPRPPAGGG GGGYSSYGNS 130 140 150 160 170 180 DNTHGRGGYR PNSRYGNTYG GDHHSTYGNP EGNMVAKIVS PIVSVVVVTL LGAAASYFKL 190 NNRRNCFRTH EPENV

References

	« Hide 'large scale' referencesShow 'large scale' references »
[1]	"Cloning of PBDX, an MIC2-related gene that spans the pseudoautosomal boundary on chromosome Xp." Ellis N.A., Ye T.Z., Patton S., German J., Goodfellow P.N., Weller P. Nat. Genet. 6:394-400(1994) [PubMed: 8054981] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA]. Tissue: Bone marrow.
[2]	"Identification of PBDX gene highly expressed in human cornea." Naoko S., Fujiki K., Kanai A., Tanaka Y., Iwata T. Submitted (MAY-2001) to the EMBL/GenBank/DDBJ databases Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 1).
[3]	"Molecular cloning and characterization of mouse PBDX." Naoko S., Tanaka Y., Iwata T. Submitted (AUG-2002) to the EMBL/GenBank/DDBJ databases Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 1).
[4]	"The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC)." The MGC Project Team Genome Res. 14:2121-2127(2004) [PubMed: 15489334] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA] (ISOFORMS 1; 2 AND 3), VARIANT ASN-60.
+	Additional computationally mapped references.

Web resources

dbRBC/BGMUT

Blood group antigen gene mutation database

Cross-references

Sequence databases
EMBLGenBankDDBJ	X96421 Genomic DNA. No translation available. AF380356 mRNA. Translation: AAL04055.1. AF534880 mRNA. Translation: AAN03481.1. BC100765 mRNA. Translation: AAI00766.1. BC100766 mRNA. Translation: AAI00767.1. BC100767 mRNA. Translation: AAI00768.1.
IPI	IPI00844291.
PIR	S43791.
RefSeq	NP_780778.1.
UniGene	Hs.179675
3D structure databases
ModBase	Search...
PTM databases
PhosphoSite	P55808.
Genome annotation databases
Ensembl	ENSG00000124343. Homo sapiens. [Contig view]
GeneID	7499.
KEGG	hsa:7499.
NMPDR	fig|9606.3.peg.32391.
Organism-specific databases
GeneCards	GC0XP002663.
H-InvDB	HIX0056172.
HGNC	HGNC:12806. XG.
MIM	314700. gene+phenotype.
PharmGKB	PA37405.
GenAtlas	Search...
Phylogenomic databases
HOVERGEN	P55808.
Gene expression databases
ArrayExpress	P55808.
Bgee	P55808.
CleanEx	HS_XG.
GermOnline	ENSG00000124343. Homo sapiens.
Family and domain databases
ProtoNet	Search...
Other Resources
NextBio	29368.
SOURCE	Search...

Entry information

Entry name

XG_HUMAN

Accession

Primary (citable) accession number: P55808
Secondary accession number(s): Q496N8 , Q496N9, Q496P0, Q71BZ5

Entry history

Integrated into UniProtKB/Swiss-Prot:	November 1, 1997
Last sequence update:	November 1, 1997
Last modified:	June 16, 2009
This is version 67 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

HPI (Human Proteome Initiative)