FEATURES

FAMILY

DESCRIPTION

Also known as TAX_HTL1C, tax. Transcriptional activator that activates both the viral long terminal repeat (LTR) and cellular promoters via activation of CREB, NF-kappa-B, SRF and AP-1 pathways. Binds to three 21 bp repeat elements located within the LTRs, referred to as Tax-responsive elements (TRE). Binding to TRE requires the interaction with CREB1 and CREBBP. Also induces chromatin remodeling of proviral LTR-mediated gene expression by recruiting the histone acetyl transferases CREBBP and EP300 to the chromatin, which results in histone acetylation. Via its interaction with IKK regulatory subunit IKBKG, Tax-1 persistently stimulates I-kappa-B kinase (IKK), resulting in constitutive activation of the transcription factor NF-kappa-B. Induction of the nuclear expression of members of the NFkB family of transcription factors, which leads to up-regulated expression of many gene promoters containing NFkB motifs. These genes include those encoding IL2, IL15, IL2RA and IL15RA, leading to autocrine IL2/IL2RA and IL15/IL15RA loops. The resulting T-cell proliferation leads to malignant transformation and to the development of adult T-cell leukemia (ATL). IL13, known to be linked to leukemogenesis, is also up-regulated by Tax-1. Interaction with PDZ domain-containing proteins induce IL2-independent growth, which may be a factor in multi-step leukemogenesis. Inhibits the action of at least three cellular tumor suppressors p53/TP53, RB1 and DLG1, and suppresses their abilities to dictate apoptosis in primary cells. Required for viral replication (By similarity). Homodimer. Interacts with host CREB1, DLG1, IKBKG, KDM4A, MAGI3 and TAX1BP1. recruits the coactivators CREBBP, EP300 and PCAF. Interaction with human CARM1 enhances Tax transactivation and promotes methylation of histone H3. Interacts with host SUV39H1 protein, leading to abrogate Tax transactivation of HTLV-1 LTR (By similarity). Interacts (via C-terminus) with host ZFP36 (via C-terminus); this interaction inhibits TAX to transactivate viral long terminal repeat (LTR) promoter (PubMed:14679154).

EXTERNAL LINKS

tax

Mutations

Mutation(s) distribution

Mutations table