Q80IU5 (X_HBVE4) Reviewed, UniProtKB/Swiss-Prot
Last modified February 19, 2014. Version 43. History...
Names and origin
|Protein names||Recommended name:|
|Organism||Hepatitis B virus genotype E (isolate Cote d'Ivoire/ABI-212/2003) (HBV-E) [Complete proteome]|
|Taxonomic identifier||489498 [NCBI]|
|Taxonomic lineage||Viruses › Retro-transcribing viruses › Hepadnaviridae › Orthohepadnavirus ›|
|Virus host||Homo sapiens (Human) [TaxID: 9606]|
Pan troglodytes (Chimpanzee) [TaxID: 9598]
|Sequence length||154 AA.|
|Protein existence||Evidence at protein level|
General annotation (Comments)
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.
May form homodimer. May interact with human CEBPA, CFLAR, CREB1, DDB1, E4F1, HBXIP, HSPD1/HSP60, NFKBIA, POLR2E and SMAD4 By similarity.
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.
Belongs to the orthohepadnavirus protein X family.
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)
|||"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].
|||"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.
|||"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.|
Hepatitis virus B database
|AB091256 Genomic DNA. Translation: BAC65106.1.|
3D structure databases
Protocols and materials databases
Family and domain databases
|InterPro||IPR000236. Transactivation_prot_X. |
|Pfam||PF00739. X. 1 hit. |
|Accession||Primary (citable) accession number: Q80IU5|
|Entry status||Reviewed (UniProtKB/Swiss-Prot)|
|Annotation program||Viral Protein Annotation Program|