ID O11883_HBV Unreviewed; 154 AA. AC O11883; DT 01-JUL-1997, integrated into UniProtKB/TrEMBL. DT 01-JUL-1997, sequence version 1. DT 05-JUN-2019, entry version 82. DE RecName: Full=Protein X {ECO:0000256|HAMAP-Rule:MF_04074, ECO:0000256|RuleBase:RU361181}; DE AltName: Full=HBx {ECO:0000256|HAMAP-Rule:MF_04074, ECO:0000256|RuleBase:RU361181}; DE AltName: Full=Peptide X {ECO:0000256|HAMAP-Rule:MF_04074, ECO:0000256|RuleBase:RU361181}; DE AltName: Full=pX {ECO:0000256|HAMAP-Rule:MF_04074, ECO:0000256|RuleBase:RU361181}; GN Name=X {ECO:0000256|HAMAP-Rule:MF_04074, GN ECO:0000256|RuleBase:RU361181, ECO:0000313|EMBL:AGA16743.1}; OS Hepatitis B virus (HBV). OC Viruses; Hepadnaviridae; Orthohepadnavirus. OX NCBI_TaxID=10407 {ECO:0000313|EMBL:AAB59970.1, ECO:0000313|Proteomes:UP000152046}; OH NCBI_TaxID=9606; Homo sapiens (Human). OH NCBI_TaxID=9598; Pan troglodytes (Chimpanzee). RN [1] {ECO:0000313|EMBL:AAB59970.1, ECO:0000313|Proteomes:UP000152046} RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. RA Rao B.S., Casey J.L., Rinaudo J.S., Korba B.E.; RT "Complete nucleotide sequence of a molecular clone of hepatitis B RT virus from the 2.2.15 cell line."; RL Submitted (MAR-1997) to the EMBL/GenBank/DDBJ databases. RN [2] {ECO:0000313|EMBL:BAE93198.1, ECO:0000313|Proteomes:UP000133680} RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. RC STRAIN=Toshima 1 {ECO:0000313|EMBL:BAE93198.1}; RX PubMed=17191017; DOI=10.1159/000098241; RA Michitaka K., Horiike N., Duong T.N., Yagura M., Harada H., RA Shibayama T., Inui A., Fujisawa T., Matsuura K., Hiasa Y., Onji M.; RT "Heterogeneity of hepatitis B virus genotype D in Japan."; RL Intervirology 50:150-155(2007). RN [3] {ECO:0000313|Proteomes:UP000100826, ECO:0000313|Proteomes:UP000123655, ECO:0000313|Proteomes:UP000130756} RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. RC STRAIN=P11 {ECO:0000313|EMBL:AGA16743.1}, P16 RC {ECO:0000313|EMBL:AGA16771.1}, P17 {ECO:0000313|EMBL:AGA16778.1}, P19 RC {ECO:0000313|EMBL:AGA16785.1}, P24 {ECO:0000313|EMBL:AGA16799.1}, and RC P29 {ECO:0000313|EMBL:AGA16764.1}; RA Alestig E.; RT "Genetic diversity of genotype D3 in acute hepatitis B."; RL Submitted (OCT-2012) to the EMBL/GenBank/DDBJ databases. RN [4] {ECO:0000313|EMBL:AUG90794.1} RP NUCLEOTIDE SEQUENCE. RC STRAIN=AD38 {ECO:0000313|EMBL:AUG90794.1}; RA Burwitz B.J., Wettengel J.M., Muck-Hausl M.A., Ringelhan M., Ko C., RA Festag M.M., Hammond K.B., Northrup M., Bimber B.N., Jacob T., RA Reed J.S., Norris R., Park B., Moller-Tank S., Esser K., Greene J.M., RA Wu H.L., Abdulhaqq S., Webb G., Sutton W.F., Klug A., Swanson T., RA Legasse A.W., Vu T.Q., Asokan A., Haigwood N.L., Protzer U., RA Sacha J.B.; RT "Hepatocytic Expression of Human Sodium-Taurocholate Cotransporting RT Polypeptide Enables Hepatitis B Virus Infection of Macaques."; RL Submitted (SEP-2017) to the EMBL/GenBank/DDBJ databases. CC -!- FUNCTION: Multifunctional protein that may modulate protein CC degradation pathways, apoptosis, transcription, signal CC transduction, cell cycle progress, and genetic stability by CC directly or indirectly interacting with host factors. CC {ECO:0000256|RuleBase:RU361181}. CC -!- FUNCTION: Multifunctional protein that plays a role in silencing CC host antiviral defenses and promoting viral transcription. Does CC not seem to be essential for HBV infection. May be directly CC involved in development of cirrhosis and liver cancer CC (hepatocellular carcinoma). Most of cytosolic activities involve CC modulation of cytosolic calcium. The effect on apoptosis is CC controversial depending on the cell types in which the studies CC have been conducted. May induce apoptosis by localizing in CC mitochondria and causing loss of mitochondrial membrane potential. CC May also modulate apoptosis by binding host CFLAR, a key regulator CC of the death-inducing signaling complex (DISC). Promotes viral CC transcription by using the host E3 ubiquitin ligase DDB1 to target CC the SMC5-SMC6 complex to proteasomal degradation. This host CC complex would otherwise bind to viral episomal DNA, and prevents CC its transcription. Moderately stimulates transcription of many CC different viral and cellular transcription elements. Promoters and CC enhancers stimulated by HBx contain DNA binding sites for NF- CC kappa-B, AP-1, AP-2, c-EBP, ATF/CREB, or the calcium-activated CC factor NF-AT. {ECO:0000256|HAMAP-Rule:MF_04074}. CC -!- SUBUNIT: May form homodimer. May interact with host CEBPA, CFLAR, CC CREB1, DDB1, E4F1, HBXIP, HSPD1/HSP60, NFKBIA, POLR2E and SMAD4. CC Interacts with host SMC5-SMC6 complex and induces its degradation. CC {ECO:0000256|HAMAP-Rule:MF_04074}. CC -!- SUBCELLULAR LOCATION: Host cytoplasm {ECO:0000256|HAMAP- CC Rule:MF_04074}. Host nucleus {ECO:0000256|HAMAP-Rule:MF_04074}. CC Host mitochondrion {ECO:0000256|HAMAP-Rule:MF_04074}. Note=Mainly CC cytoplasmic as only a fraction is detected in the nucleus. In CC cytoplasm, a minor fraction associates with mitochondria or CC proteasomes. {ECO:0000256|HAMAP-Rule:MF_04074}. CC -!- PTM: A fraction may be phosphorylated in insect cells and HepG2 CC cells, a human hepatoblastoma cell line. Phosphorylated in vitro CC by host protein kinase C or mitogen-activated protein kinase. N- CC acetylated in insect cells. {ECO:0000256|HAMAP-Rule:MF_04074}. CC -!- SIMILARITY: Belongs to the orthohepadnavirus protein X family. CC {ECO:0000256|HAMAP-Rule:MF_04074, ECO:0000256|RuleBase:RU361181}. CC --------------------------------------------------------------------------- CC Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms CC Distributed under the Creative Commons Attribution (CC BY 4.0) License CC --------------------------------------------------------------------------- DR EMBL; U95551; AAB59970.1; -; Genomic_DNA. DR EMBL; JX898686; AGA16743.1; -; Genomic_DNA. DR EMBL; JX898689; AGA16764.1; -; Genomic_DNA. DR EMBL; JX898690; AGA16771.1; -; Genomic_DNA. DR EMBL; JX898691; AGA16778.1; -; Genomic_DNA. DR EMBL; JX898692; AGA16785.1; -; Genomic_DNA. DR EMBL; JX898694; AGA16799.1; -; Genomic_DNA. DR EMBL; MF967563; AUG90794.1; -; Genomic_DNA. DR EMBL; AB210819; BAE93198.1; -; Genomic_DNA. DR SMR; O11883; -. DR Proteomes; UP000100826; Genome. DR Proteomes; UP000123655; Genome. DR Proteomes; UP000130756; Genome. DR Proteomes; UP000133680; Genome. DR Proteomes; UP000138899; Genome. DR Proteomes; UP000152046; Genome. DR Proteomes; UP000180829; Genome. DR Proteomes; UP000180868; Genome. DR GO; GO:0033650; C:host cell mitochondrion; IEA:UniProtKB-SubCell. DR GO; GO:0042025; C:host cell nucleus; IEA:UniProtKB-SubCell. DR GO; GO:0039652; P:activation by virus of host NF-kappaB transcription factor activity; IEA:UniProtKB-UniRule. DR GO; GO:0039592; P:suppression by virus of G2/M transition of host mitotic cell cycle; IEA:UniProtKB-UniRule. DR GO; GO:0006351; P:transcription, DNA-templated; IEA:UniProtKB-UniRule. DR GO; GO:0019079; P:viral genome replication; IEA:UniProtKB-UniRule. DR HAMAP; MF_04074; HBV_X; 1. DR InterPro; IPR000236; Transactivation_prot_X. DR Pfam; PF00739; X; 1. PE 3: Inferred from homology; KW Activation of host NF-kappa-B by virus {ECO:0000256|HAMAP- KW Rule:MF_04074}; Activator {ECO:0000256|HAMAP-Rule:MF_04074}; KW Apoptosis {ECO:0000256|HAMAP-Rule:MF_04074}; KW Complete proteome {ECO:0000313|Proteomes:UP000100826, KW ECO:0000313|Proteomes:UP000123655, ECO:0000313|Proteomes:UP000130756, KW ECO:0000313|Proteomes:UP000133680}; KW Host cytoplasm {ECO:0000256|HAMAP-Rule:MF_04074, KW ECO:0000256|RuleBase:RU361181}; KW Host G2/M cell cycle arrest by virus {ECO:0000256|HAMAP- KW Rule:MF_04074}; KW Host mitochondrion {ECO:0000256|HAMAP-Rule:MF_04074, KW ECO:0000256|RuleBase:RU361181}; KW Host nucleus {ECO:0000256|HAMAP-Rule:MF_04074, KW ECO:0000256|RuleBase:RU361181}; KW Host-virus interaction {ECO:0000256|HAMAP-Rule:MF_04074, KW ECO:0000256|RuleBase:RU361181}; KW Modulation of host cell cycle by virus {ECO:0000256|HAMAP- KW Rule:MF_04074}; Transcription {ECO:0000256|HAMAP-Rule:MF_04074}; KW Transcription regulation {ECO:0000256|HAMAP-Rule:MF_04074}. FT REGION 68 117 Mitochondrial targeting sequence. FT {ECO:0000256|HAMAP-Rule:MF_04074}. SQ SEQUENCE 154 AA; 16611 MW; 895800BDF24CEA17 CRC64; MAARLCCQLD PARDVLCLRP VGAESCGRPF SGSLGTLSSP SPSAVPTDHG AHLSLRGLPV CAFSSAGPCA LRFTSARRME TTVNAHRMLP KVLHKRTLGL SAMSTTDLEA YFKDCLFKDW EELGEEIRLK VFVLGGCRHK LVCAPAPCNF FTSA //