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P24109 (TAT_HV2CA) Reviewed, UniProtKB/Swiss-Prot

Last modified February 19, 2014. Version 70. Feed History...

Clusters with 100%, 90%, 50% identity | Documents (1) | Third-party data text xml rdf/xml gff fasta
to top of pageNames·Attributes·General annotation·Ontologies·Alt products·Sequence annotation·Sequences·References·Cross-refs·Entry info·DocumentsCustomize order

Names and origin

Protein namesRecommended name:
Protein Tat
Alternative name(s):
Transactivating regulatory protein
Gene names
Name:tat
OrganismHuman immunodeficiency virus type 2 subtype A (isolate CAM2) (HIV-2) [Complete proteome]
Taxonomic identifier11715 [NCBI]
Taxonomic lineageVirusesRetro-transcribing virusesRetroviridaeOrthoretrovirinaeLentivirusPrimate lentivirus group
Virus hostHomo sapiens (Human) [TaxID: 9606]

Protein attributes

Sequence length133 AA.
Sequence statusComplete.
Protein existenceInferred from homology

General annotation (Comments)

Function

Nuclear transcriptional activator of viral gene expression, that is essential for viral transcription from the LTR promoter and replication. Acts as a sequence-specific molecular adapter, directing components of the cellular transcription machinery to the viral RNA to promote processive transcription elongation by the RNA polymerase II (RNA pol II) complex, thereby increasing the level of full-length transcripts. In the absence of Tat, the RNA Pol II generates short or non-processive transcripts that terminate at approximately 60 bp from the initiation site. Tat associates with the CCNT1/cyclin-T1 component of the P-TEFb complex (CDK9 and CCNT1), which promotes RNA chain elongation. This binding increases Tat's affinity for a hairpin structure at the 5'-end of all nascent viral mRNAs referred to as the transactivation responsive RNA element (TAR RNA) and allows Tat/P-TEFb complex to bind cooperatively to TAR RNA. The CDK9 component of P-TEFb and other Tat-activated kinases hyperphosphorylate the C-terminus of RNA Pol II that becomes stabilized and much more processive By similarity.

Extracellular circulating Tat can be endocytosed by surrounding uninfected cells via the binding to several surface receptors. Endosomal low pH allows Tat to cross the endosome membrane to enter the cytosol and eventually further translocate into the nucleus, thereby inducing severe cell dysfunctions ranging from cell activation to cell death. Through By similarity.

Subunit structure

Interacts with host CCNT1. Associates with the P-TEFb complex composed at least of Tat, P-TEFb (CDK9 and CCNT1), TAR RNA, RNA Pol II. Interacts with CCNT2; the resulting complex is unable to bind to TAR RNA By similarity.

Subcellular location

Host nucleushost nucleolus By similarity.

Domain

The Arg-rich RNA-binding region binds the TAR RNA. This region also mediates the nuclear localization By similarity.

Post-translational modification

The phosphorylation by CDK9 does not seem to be important for transactivation function By similarity.

Sequence similarities

Belongs to the lentiviruses Tat family.

Ontologies

Keywords
   Biological processHost-virus interaction
Transcription
Transcription regulation
   Cellular componentHost nucleus
   Coding sequence diversityAlternative splicing
   DiseaseAIDS
   LigandRNA-binding
   Molecular functionActivator
   PTMPhosphoprotein
   Technical termComplete proteome
Gene Ontology (GO)
   Biological_processtranscription, DNA-templated

Inferred from electronic annotation. Source: UniProtKB-KW

viral process

Inferred from electronic annotation. Source: UniProtKB-KW

   Cellular_componenthost cell nucleolus

Inferred from electronic annotation. Source: UniProtKB-SubCell

   Molecular_functionRNA binding

Inferred from electronic annotation. Source: UniProtKB-KW

sequence-specific DNA binding transcription factor activity

Inferred from electronic annotation. Source: InterPro

Complete GO annotation...

Alternative products

This entry describes 2 isoforms produced by alternative splicing. [Align] [Select]
Isoform Long (identifier: P24109-1)

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 Short (identifier: P24109-2)

The sequence of this isoform differs from the canonical sequence as follows:
     103-133: Missing.
Note: No experimental confirmation available. Expressed in the late stage of the infection cycle, when unspliced viral RNAs are exported to the cytoplasm by the viral Rev protein.

Sequence annotation (Features)

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifier

Molecule processing

Chain1 – 133133Protein Tat
PRO_0000085368

Regions

Region53 – 6917Cysteine-rich By similarity
Region70 – 8011Core By similarity
Motif81 – 9313Nuclear localization signal, and RNA-binding (TAR) By similarity

Amino acid modifications

Modified residue881Phosphothreonine; by host CDK9 By similarity
Modified residue971Phosphoserine; by host CDK9 By similarity

Natural variations

Alternative sequence103 – 13331Missing in isoform Short.
VSP_022438

Sequences

Sequence LengthMass (Da)Tools
Isoform Long [UniParc].

Last modified March 1, 1992. Version 1.
Checksum: CFAB978387B3C1FD

FASTA13314,850
        10         20         30         40         50         60 
MLDMETPLKE PESSLGSCNE PSSRTSGQDA TTQELAKLGE EILSQLYQPL EECDNSCYCK 

        70         80         90        100        110        120 
RCCYHCQLCF LKKGLGICYD RKGRRRRTPK KAKAHSSSAS DKSISTRTRN SQPAKKQKKT 

       130 
LEATVETDPG LGR 

« Hide

Isoform Short [UniParc].

Checksum: 6E58535C331C391A
Show »

FASTA10211,469

References

[1]"Nucleotide sequence of a Guinea-Bissau-derived human immunodeficiency virus type 2 proviral clone (HIV-2CAM2)."
Tristem M., Hill F., Karpas A.
J. Gen. Virol. 72:721-724(1991) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].
[2]"Decoding Tat: the biology of HIV Tat posttranslational modifications."
Hetzer C., Dormeyer W., Schnolzer M., Ott M.
Microbes Infect. 7:1364-1369(2005) [PubMed] [Europe PMC] [Abstract]
Cited for: REVIEW, ALTERNATIVE SPLICING.

Cross-references

Sequence databases

EMBL
GenBank
DDBJ
D00835 Genomic DNA. Translation: BAA00714.1.
PIRTNLJCA. I38475.

3D structure databases

ProteinModelPortalP24109.
ModBaseSearch...
MobiDBSearch...

Protocols and materials databases

StructuralBiologyKnowledgebaseSearch...

Family and domain databases

Gene3D4.10.20.10. 1 hit.
InterProIPR001831. IV_Tat.
[Graphical view]
PfamPF00539. Tat. 1 hit.
[Graphical view]
PRINTSPR00055. HIVTATDOMAIN.
ProtoNetSearch...

Entry information

Entry nameTAT_HV2CA
AccessionPrimary (citable) accession number: P24109
Entry history
Integrated into UniProtKB/Swiss-Prot: March 1, 1992
Last sequence update: March 1, 1992
Last modified: February 19, 2014
This is version 70 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