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Q80IU5 (X_HBVE4) Reviewed, UniProtKB/Swiss-Prot

Last modified February 19, 2014. Version 43. Feed History...

Clusters with 100%, 90%, 50% identity | Documents (2) | Third-party data text xml rdf/xml gff fasta
to top of pageNames·Attributes·General annotation·Ontologies·Sequence annotation·Sequences·References·Web links·Cross-refs·Entry info·DocumentsCustomize order

Names and origin

Protein namesRecommended name:
Protein X
Alternative name(s):
HBx
Peptide X
pX
Gene names
Name:X
OrganismHepatitis B virus genotype E (isolate Cote d'Ivoire/ABI-212/2003) (HBV-E) [Complete proteome]
Taxonomic identifier489498 [NCBI]
Taxonomic lineageVirusesRetro-transcribing virusesHepadnaviridaeOrthohepadnavirus
Virus hostHomo sapiens (Human) [TaxID: 9606]
Pan troglodytes (Chimpanzee) [TaxID: 9598]

Protein attributes

Sequence length154 AA.
Sequence statusComplete.
Protein existenceEvidence at protein level

General annotation (Comments)

Function

Multifunctional protein that may modulate protein degradation pathways, apoptosis, transcription, signal transduction, cell cycle progress, and genetic stability by directly or indirectly interacting with hosts factors. Does not seem to be essential for HBV infection. May be directly involved in development of cirrhosis and liver cancer (hepatocellular carcinoma). Most of cytosolic activities involve modulation of cytosolic calcium. The effect on apoptosis is controversial depending on the cell types in which the studies have been conducted. By binding to human DDB1, may affect cell viability and stimulate genome replication. May induce apoptosis by localizing in mitochondria and causing loss of mitochondrial membrane potential. May also modulate apoptosis by binding human CFLAR, a key regulator of the death-inducing signaling complex (DISC). Moderately stimulates transcription of many different viral and cellular transcription elements. Promoters and enhancers stimulated by HBx contain DNA binding sites for NF-kappa-B, AP-1, AP-2, c-EBP, ATF/CREB, or the calcium-activated factor NF-AT. May bind bZIP transcription factors like CREB1 By similarity.

Subunit structure

May form homodimer. May interact with human CEBPA, CFLAR, CREB1, DDB1, E4F1, HBXIP, HSPD1/HSP60, NFKBIA, POLR2E and SMAD4 By similarity.

Subcellular location

Host cytoplasm. Host nucleus. Host mitochondrion. Note: Mainly cytoplasmic as only a fraction is detected in the nucleus. In cytoplasm, a minor fraction associates with mitochondria or proteasomes By similarity.

Sequence similarities

Belongs to the orthohepadnavirus protein X family.

Caution

Transcriptional activities should be taken with a grain of salt. As of 2007, all studies demonstrating in vivo interaction between protein X and transcriptional components were performed with significant overexpression of both proteins and in the absence of viral infection.

Sequence annotation (Features)

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifier

Molecule processing

Chain1 – 154154Protein X
PRO_0000319917

Regions

Region68 – 11750Mitochondrial targeting sequence By similarity

Secondary structure

... 154
Helix Strand Turn

Details...

Sequences

Sequence LengthMass (Da)Tools
Q80IU5 [UniParc].

Last modified June 1, 2003. Version 1.
Checksum: B542A553E99A333D

FASTA15416,471
        10         20         30         40         50         60 
MAARLCCQLD PARDVLCLRP VGAESCGRPV SGSLGGLSSP SPSAVPADHG AHLSLRGLPV 

        70         80         90        100        110        120 
CAFSSAGPCA LRFTSARRME TTVNAHQILP KVLHKRTLGL SAMSTTDLEA YFKDCLFKDW 

       130        140        150 
EELGEEIRLK VFVLGGCRHK LVCVPAPCNF FTSA 

« Hide

References

[1]"Distribution of Hepatitis B Virus (HBV) genotypes among HBV carriers in Cote d'Ivoire: complete genome sequence and phylogenetic relatedness of HBV genotype E."
Suzuki S., Sugauchi F., Orito E., Kato H., Usuda S., Siransy L., Arita I., Sakamoto Y., Yoshihara N., El-Gohary A., Ueda R., Mizokami M.
Submitted (SEP-2002) to the EMBL/GenBank/DDBJ databases
Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].
[2]"The enigmatic X gene of hepatitis B virus."
Bouchard M.J., Schneider R.J.
J. Virol. 78:12725-12734(2004) [PubMed] [Europe PMC] [Abstract]
Cited for: REVIEW.
[3]"Molecular functions and biological roles of hepatitis B virus x protein."
Tang H., Oishi N., Kaneko S., Murakami S.
Cancer Sci. 97:977-983(2006) [PubMed] [Europe PMC] [Abstract]
Cited for: REVIEW.
+Additional computationally mapped references.

Web resources

HepSEQ

Hepatitis virus B database

Cross-references

Sequence databases

EMBL
GenBank
DDBJ
AB091256 Genomic DNA. Translation: BAC65106.1.

3D structure databases

PDBe
RCSB PDB
PDBj
EntryMethodResolution (Å)ChainPositionsPDBsum
3I7HX-ray2.90B88-101[»]
ModBaseSearch...
MobiDBSearch...

Protocols and materials databases

StructuralBiologyKnowledgebaseSearch...

Family and domain databases

InterProIPR000236. Transactivation_prot_X.
[Graphical view]
PfamPF00739. X. 1 hit.
[Graphical view]
ProtoNetSearch...

Other

EvolutionaryTraceQ80IU5.

Entry information

Entry nameX_HBVE4
AccessionPrimary (citable) accession number: Q80IU5
Entry history
Integrated into UniProtKB/Swiss-Prot: February 26, 2008
Last sequence update: June 1, 2003
Last modified: February 19, 2014
This is version 43 of the entry and version 1 of the sequence. [Complete history]
Entry statusReviewed (UniProtKB/Swiss-Prot)
Annotation programViral Protein Annotation Program

Relevant documents

SIMILARITY comments

Index of protein domains and families

PDB cross-references

Index of Protein Data Bank (PDB) cross-references