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18  structures 1009  species 0  interactions 1584  sequences 47  architectures

Family: TAP_C (PF03943)

Summary: TAP C-terminal domain

Pfam includes annotations and additional family information from a range of different sources. These sources can be accessed via the tabs below.

This is the Wikipedia entry entitled "NXF1". More...

NXF1 Edit Wikipedia article

PDB 1fo1 EBI.jpg
Available structures
PDBOrtholog search: PDBe RCSB
AliasesNXF1, MEX67, TAP, nuclear RNA export factor 1
External IDsOMIM: 602647 MGI: 1858330 HomoloGene: 38176 GeneCards: NXF1
Gene location (Human)
Chromosome 11 (human)
Chr.Chromosome 11 (human)[1]
Chromosome 11 (human)
Genomic location for NXF1
Genomic location for NXF1
Band11q12.3Start62,792,123 bp[1]
End62,806,302 bp[1]
RNA expression pattern
PBB GE NXF1 208922 s at fs.png

PBB GE NXF1 220934 s at fs.png
More reference expression data
RefSeq (mRNA)



RefSeq (protein)



Location (UCSC)Chr 11: 62.79 – 62.81 MbChr 19: 8.76 – 8.77 Mb
PubMed search[3][4]
View/Edit HumanView/Edit Mouse

Nuclear RNA export factor 1, also known as NXF1 or TAP, is a protein which in humans is encoded by the NXF1 gene.[5][6]


This gene is one member of a family of nuclear RNA export factor genes. Common domain features of this family are a noncanonical RNP-type RNA-binding domain (RBD), 4 leucine-rich repeats (LRRs), a nuclear transport factor 2 (NTF2)-like domain that allows heterodimerization with NTF2-related export protein-1 (NXT1), and a ubiquitin-associated domain that mediates interactions with nucleoporins. Alternative splicing results in transcript variants. The LRRs and NTF2-like domains are required for export activity. The encoded protein of this gene shuttles between the nucleus and the cytoplasm and binds in vivo to poly(A)+ RNA. It is the vertebrate homologue of the yeast protein Mex67p.[6][7] The encoded protein overcomes the mRNA export block caused by the presence of saturating amounts of CTE (constitutive transport element) RNA of type D retroviruses.[8] A variant allele of the homologous Nxf1 gene in mice suppresses a class of mutations caused by integration of an endogenous retrovirus (intracisternal A particle) into an intron.[9][10]


NXF1 has been shown to interact with TNPO2,[11] MAGOH,[12] U2 small nuclear RNA auxiliary factor 1,[13] DHX9,[14] HuD[15] and NUP214.[16][17]

Tap protein

In molecular biology, another name for the protein NXF1 is TAP. In particular this entry focuses on the C-terminal domain, which also contains the UBA(protein domain).

PDB 1oai EBI.jpg
complex between tap uba domain and fxfg nucleoporin peptide
Pfam clanCL0214

This entry contains the NXF family of shuttling transport receptors for nuclear export of mRNA, which include:

  • vertebrate mRNA export factor TAP or nuclear RNA export factor 1 (NXF1).
  • Caenorhabditis elegans nuclear RNA export factor 1 (nxf-1).
  • yeast mRNA export factor MEX67. Members of the NXF family have a modular structure. A nuclear localization sequence and a noncanonical RNA recognition motif (RRM) (see PROSITEDOC) followed by four LRR repeats are located in its N-terminal half. The C-terminal half contains a NTF2 domain (see [href=" PROSITEDOC]) followed by a second domain, TAP-C. The TAP-C domain is important for binding to FG repeat-containing nuclear pore proteins (FG-nucleoporins) and is sufficient to mediate nuclear shuttling.[18][19]

The Tap-C domain is made of four alpha helices packed against each other. The arrangement of helices 1, 2 and 3 is similar to that seen in a UBA fold. and is joined to the next module by flexible 12-residue Pro-rich linker.[18][19]


Nuclear export of mRNAs is mediated by the Tap protein.


Tap can form a multimeric complex with itself and with other members of the NXF family. Three functional domains of Tap have been well characterized: the RNA-binding domain, the Nuclear Transport Factor 2 (NTF2)-like domain, and the ubiquitin-associated (UBA) domain.


  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000162231 - Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000010097 - Ensembl, May 2017
  3. ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. ^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. ^ Yoon DW, Lee H, Seol W, DeMaria M, Rosenzweig M, Jung JU (May 1997). "Tap: a novel cellular protein that interacts with tip of herpesvirus saimiri and induces lymphocyte aggregation". Immunity. 6 (5): 571–82. doi:10.1016/S1074-7613(00)80345-3. PMID 9175835.
  6. ^ a b Grüter P, Tabernero C, von Kobbe C, Schmitt C, Saavedra C, Bachi A, Wilm M, Felber BK, Izaurralde E (April 1998). "TAP, the human homolog of Mex67p, mediates CTE-dependent RNA export from the nucleus". Molecular Cell. 1 (5): 649–59. doi:10.1016/S1097-2765(00)80065-9. PMID 9660949.
  7. ^ Katahira J, Strässer K, Podtelejnikov A, Mann M, Jung JU, Hurt E (May 1999). "The Mex67p-mediated nuclear mRNA export pathway is conserved from yeast to human". The EMBO Journal. 18 (9): 2593–609. doi:10.1093/emboj/18.9.2593. PMC 1171339. PMID 10228171.
  8. ^ "Entrez Gene: NXF1 nuclear RNA export factor 1".
  9. ^ Floyd JA, Gold DA, Concepcion D, Poon TH, Wang X, Keithley E, Chen D, Ward EJ, Chinn SB, Friedman RA, Yu HT, Moriwaki K, Shiroishi T, Hamilton BA (November 2003). "A natural allele of Nxf1 suppresses retrovirus insertional mutations". Nature Genetics. 35 (3): 221–8. doi:10.1038/ng1247. PMC 2756099. PMID 14517553.
  10. ^ Concepcion D, Flores-García L, Hamilton BA (May 2009). "Multipotent genetic suppression of retrotransposon-induced mutations by Nxf1 through fine-tuning of alternative splicing". PLoS Genetics. 5 (5): e1000484. doi:10.1371/journal.pgen.1000484. PMC 2674570. PMID 19436707.
  11. ^ Shamsher MK, Ploski J, Radu A (October 2002). "Karyopherin beta 2B participates in mRNA export from the nucleus". Proceedings of the National Academy of Sciences of the United States of America. 99 (22): 14195–9. Bibcode:2002PNAS...9914195S. doi:10.1073/pnas.212518199. PMC 137860. PMID 12384575.
  12. ^ Kataoka N, Diem MD, Kim VN, Yong J, Dreyfuss G (November 2001). "Magoh, a human homolog of Drosophila mago nashi protein, is a component of the splicing-dependent exon-exon junction complex". The EMBO Journal. 20 (22): 6424–33. doi:10.1093/emboj/20.22.6424. PMC 125744. PMID 11707413.
  13. ^ Zolotukhin AS, Tan W, Bear J, Smulevitch S, Felber BK (February 2002). "U2AF participates in the binding of TAP (NXF1) to mRNA". The Journal of Biological Chemistry. 277 (6): 3935–42. doi:10.1074/jbc.M107598200. PMID 11724776.
  14. ^ Tang H, Wong-Staal F (October 2000). "Specific interaction between RNA helicase A and Tap, two cellular proteins that bind to the constitutive transport element of type D retrovirus". The Journal of Biological Chemistry. 275 (42): 32694–700. doi:10.1074/jbc.M003933200. PMID 10924507.
  15. ^ Saito K, Fujiwara T, Katahira J, Inoue K, Sakamoto H (August 2004). "TAP/NXF1, the primary mRNA export receptor, specifically interacts with a neuronal RNA-binding protein HuD". Biochemical and Biophysical Research Communications. 321 (2): 291–7. doi:10.1016/j.bbrc.2004.06.140. PMID 15358174.
  16. ^ Herold A, Suyama M, Rodrigues JP, Braun IC, Kutay U, Carmo-Fonseca M, Bork P, Izaurralde E (December 2000). "TAP (NXF1) belongs to a multigene family of putative RNA export factors with a conserved modular architecture". Molecular and Cellular Biology. 20 (23): 8996–9008. doi:10.1128/MCB.20.23.8996-9008.2000. PMC 86553. PMID 11073998.
  17. ^ Schmitt I, Gerace L (November 2001). "In vitro analysis of nuclear transport mediated by the C-terminal shuttle domain of Tap". The Journal of Biological Chemistry. 276 (45): 42355–63. doi:10.1074/jbc.M103916200. PMID 11551912.
  18. ^ a b Grant RP, Hurt E, Neuhaus D, Stewart M (April 2002). "Structure of the C-terminal FG-nucleoporin binding domain of Tap/NXF1". Nature Structural Biology. 9 (4): 247–51. doi:10.1038/nsb773. PMID 11875519.
  19. ^ a b Suyama M, Doerks T, Braun IC, Sattler M, Izaurralde E, Bork P (July 2000). "Prediction of structural domains of TAP reveals details of its interaction with p15 and nucleoporins". EMBO Reports. 1 (1): 53–8. doi:10.1038/sj.embor.embor627 (inactive 2019-08-20). PMC 1083685. PMID 11256625.

External links

  • PDBe-KB provides an overview of all the structure information available in the PDB for Human Nuclear RNA export factor 1 (NXF1)

This page is based on a Wikipedia article. The text is available under the Creative Commons Attribution/Share-Alike License.

This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

TAP C-terminal domain Provide feedback

The vertebrate Tap protein is a member of the NXF family of shuttling transport receptors for nuclear export of mRNA. Tap has a modular structure, and its most C-terminal domain is important for binding to FG repeat-containing nuclear pore proteins (FG-nucleoporins) and is sufficient to mediate nuclear shuttling [1]. The structure of the C-terminal domain is composed of four helices [1]. The structure is related to the UBA domain.

Literature references

  1. Grant RP, Hurt E, Neuhaus D, Stewart M; , Nat Struct Biol 2002;9:247-251.: Structure of the C-terminal FG-nucleoporin binding domain of Tap/NXF1. PUBMED:11875519 EPMC:11875519

Internal database links

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR005637

The vertebrate Tap protein is a member of the NXF family of shuttling transport receptors for nuclear export of mRNA. Tap has a modular structure, and its most C-terminal domain is important for binding to FG repeat-containing nuclear pore proteins (FG-nucleoporins) and is sufficient to mediate nuclear shuttling [ PUBMED:11875519 ]. The structure of the C-terminal domain is composed of four helices [ PUBMED:11875519 ]. The structure is related to the UBA domain.

The NXF family of mRNA nuclear export factors includes vertebrate NXF1 (also called tip-associated protein or mRNA export factor TAP), NXF2 (also called cancer/testis antigen CT39 or TAP-like protein TAPL-2), Caenorhabditis elegans NXF1 (ceNXF1), Saccharomyces cerevisiae mRNA nuclear export factor Mex67p and similar proteins. NXF proteins can stimulate nuclear export of mRNAs and facilitate the export of unspliced viral mRNA containing the constitutive transport element. An NXF protein is multi-domain with a nuclear localization sequence (NLS), a non-canonical mRNA-binding domain, and four leucine-rich repeats (LLR) at the N-terminal region. Its C-terminal part contains a NTF2-like domain and a ubiquitin-associated (UBA)-like domain, joined by flexible Pro-rich linker. Caenorhabditis elegans NXF1 are essential for the nuclear export of poly(A)+mRNA. In budding yeast, Mex67p binds mRNAs through its adaptor Yra1/REF. It also interacts directly with Nab2, an essential shuttling mRNA-binding protein required for export. Moreover, Mex67p associates with both nuclear pore protein (nucleoporin) FG repeats and Hpr1, a component of the TREX/THO complex linking transcription and export [ PUBMED:11875519 , PUBMED:20810649 , PUBMED:10567585 , PUBMED:11073998 , PUBMED:11583626 , PUBMED:12581645 , PUBMED:19401465 , PUBMED:11060011 , PUBMED:11256625 , PUBMED:10668806 , PUBMED:11259411 , PUBMED:9660949 , PUBMED:9175835 , PUBMED:10454577 , PUBMED:10323864 , PUBMED:10202158 ].

Gene Ontology

The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.

Domain organisation

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Pfam Clan

This family is a member of clan UBA (CL0214), which has the following description:

This superfamily includes domains related to the UBA domain. These domains are often involved in ubiquitin binding.

The clan contains the following 21 members:



We store a range of different sequence alignments for families. As well as the seed alignment from which the family is built, we provide the full alignment, generated by searching the sequence database (reference proteomes) using the family HMM. We also generate alignments using four representative proteomes (RP) sets and the UniProtKB sequence database. More...

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Seed source: Bateman A
Previous IDs: none
Type: Domain
Sequence Ontology: SO:0000417
Author: Bateman A
Number in seed: 138
Number in full: 1584
Average length of the domain: 47.20 aa
Average identity of full alignment: 36 %
Average coverage of the sequence by the domain: 7.93 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 57096847 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 21.3 21.3
Trusted cut-off 21.3 21.3
Noise cut-off 21.1 21.2
Model length: 49
Family (HMM) version: 15
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For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the TAP_C domain has been found. There are 18 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein sequence.

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