Nuclear RNA export factor 1, also known as NXF1orTAP, 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]
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).
TAP_C | |||||||||
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Identifiers | |||||||||
Symbol | TAP_C | ||||||||
Pfam | PF03943 | ||||||||
Pfam clan | CL0214 | ||||||||
InterPro | IPR005637 | ||||||||
SCOP2 | 1go5 / SCOPe / SUPFAM | ||||||||
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This entry contains the NXF family of shuttling transport receptors for nuclear export of mRNA, which include:
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.
PDB gallery
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1fo1: CRYSTAL STRUCTURE OF THE RNA-BINDING DOMAIN OF THE MRNA EXPORT FACTOR TAP
1ft8: CRYSTAL STRUCTURE OF THE RNA-BINDING DOMAIN OF THE MRNA EXPORT FACTOR TAP
1go5: STRUCTURE OF THE C-TERMINAL FG-BINDING DOMAIN OF HUMAN TAP
1jkg: Structural basis for the recognition of a nucleoporin FG-repeat by the NTF2-like domain of TAP-p15 mRNA nuclear export factor
1jn5: Structural basis for the recognition of a nucleoporin FG-repeat by the NTF2-like domain of TAP-p15 mRNA export factor
1koh: THE CRYSTAL STRUCTURE AND MUTATIONAL ANALYSIS OF A NOVEL RNA-BINDING DOMAIN FOUND IN THE HUMAN TAP NUCLEAR MRNA EXPORT FACTOR
1koo: THE CRYSTAL STRUCTURE AND MUTATIONAL ANALYSIS OF A NOVEL RNA-BINDING DOMAIN FOUND IN THE HUMAN TAP NUCLEAR MRNA EXPORT FACTOR
1oai: COMPLEX BETWEEN TAP UBA DOMAIN AND FXFG NUCLEOPORIN PEPTIDE
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