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Protein

Protein Tat

Gene

tat

Organism
Human immunodeficiency virus type 2 subtype B (isolate EHO) (HIV-2)
Status
Reviewed-Annotation score: Annotation score: 3 out of 5-Protein inferred from homologyi

Functioni

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).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).By similarity

GO - Molecular functioni

GO - Biological processi

Complete GO annotation...

Keywords - Molecular functioni

Activator

Keywords - Biological processi

Host-virus interaction, Transcription, Transcription regulation

Keywords - Ligandi

RNA-binding

Names & Taxonomyi

Protein namesi
Recommended name:
Protein Tat
Alternative name(s):
Transactivating regulatory protein
Gene namesi
Name:tat
OrganismiHuman immunodeficiency virus type 2 subtype B (isolate EHO) (HIV-2)
Taxonomic identifieri388821 [NCBI]
Taxonomic lineageiVirusesRetro-transcribing virusesRetroviridaeOrthoretrovirinaeLentivirusPrimate lentivirus group
Virus hostiHomo sapiens (Human) [TaxID: 9606]
Proteomesi
  • UP000007423 Componenti: Genome

Subcellular locationi

GO - Cellular componenti

Complete GO annotation...

Keywords - Cellular componenti

Host nucleus

Pathology & Biotechi

Keywords - Diseasei

AIDS

PTM / Processingi

Molecule processing

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Chaini1 – 138138Protein TatPRO_0000244862Add
BLAST

Amino acid modifications

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Modified residuei92 – 921Phosphoserine; by host CDK9By similarity

Post-translational modificationi

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

Keywords - PTMi

Phosphoprotein

Interactioni

Subunit structurei

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).By similarity

Structurei

3D structure databases

ProteinModelPortaliQ89745.
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Region

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Regioni50 – 6617Cysteine-richBy similarityAdd
BLAST
Regioni67 – 7711CoreBy similarityAdd
BLAST

Motif

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Motifi78 – 8811Nuclear localization signal, and RNA-binding (TAR)By similarityAdd
BLAST

Domaini

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

Sequence similaritiesi

Belongs to the lentiviruses Tat family.Curated

Family and domain databases

Gene3Di4.10.20.10. 1 hit.
InterProiIPR001831. IV_Tat.
[Graphical view]
PfamiPF00539. Tat. 1 hit.
[Graphical view]
PRINTSiPR00055. HIVTATDOMAIN.

Sequences (2)i

Sequence statusi: Complete.

This entry describes 2 isoformsi produced by alternative splicing. AlignAdd to basket

Isoform Long (identifier: Q89745-1) [UniParc]FASTAAdd to basket

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.

« Hide

        10         20         30         40         50
MEIPLKEQES SLNSSSGHSS STSEGVANTQ GLDNRGEEIL SQLYRPLKAC
60 70 80 90 100
SNTCYCKKCS YHCQLCFLKK GLGICYERSR KRSSKRAKTT TSSAPNESLS
110 120 130
ARTGDSQPTK KQKKEVETTR ATDLGPGRSN TSTSRFAN
Length:138
Mass (Da):15,121
Last modified:January 23, 2007 - v2
Checksum:iB85F7D16C8C34F23
GO
Isoform Short (identifier: Q89745-2) [UniParc]FASTAAdd to basket

The sequence of this isoform differs from the canonical sequence as follows:
     98-138: 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.
Show »
Length:97
Mass (Da):10,729
Checksum:i6F0CF1DD7FDA4858
GO

Sequence cautioni

The sequence AAC54471 differs from that shown. Reason: Erroneous gene model prediction. Curated

Alternative sequence

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Alternative sequencei98 – 13841Missing in isoform Short. CuratedVSP_022440Add
BLAST

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
U27200 Genomic DNA. Translation: AAC54471.1. Sequence problems.

Keywords - Coding sequence diversityi

Alternative splicing

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
U27200 Genomic DNA. Translation: AAC54471.1. Sequence problems.

3D structure databases

ProteinModelPortaliQ89745.
ModBaseiSearch...
MobiDBiSearch...

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Family and domain databases

Gene3Di4.10.20.10. 1 hit.
InterProiIPR001831. IV_Tat.
[Graphical view]
PfamiPF00539. Tat. 1 hit.
[Graphical view]
PRINTSiPR00055. HIVTATDOMAIN.
ProtoNetiSearch...

Entry informationi

Entry nameiTAT_HV2EH
AccessioniPrimary (citable) accession number: Q89745
Entry historyi
Integrated into UniProtKB/Swiss-Prot: July 11, 2006
Last sequence update: January 23, 2007
Last modified: December 9, 2015
This is version 74 of the entry and version 2 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programViral Protein Annotation Program

Miscellaneousi

Keywords - Technical termi

Complete proteome

Documents

  1. SIMILARITY comments
    Index of protein domains and families

Similar proteinsi

Links to similar proteins from the UniProt Reference Clusters (UniRef) at 100%, 90% and 50% sequence identity:
100%UniRef100 combines identical sequences and sub-fragments with 11 or more residues from any organism into one UniRef entry.
90%UniRef90 is built by clustering UniRef100 sequences that have at least 90% sequence identity to, and 80% overlap with, the longest sequence (a.k.a seed sequence).
50%UniRef50 is built by clustering UniRef90 seed sequences that have at least 50% sequence identity to, and 80% overlap with, the longest sequence in the cluster.