| NXF1 | |||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
 | |||||||||||||||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||
| Identifiers | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Aliases | NXF1 , MEX67, TAP, nuclear RNA export factor 1 | ||||||||||||||||||||||||||||||||||||||||||||||||||
| External IDs | OMIM: 602647 MGI: 1858330 HomoloGene: 38176 GeneCards: NXF1 | ||||||||||||||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||
| Wikidata | |||||||||||||||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||
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]
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 | |||||||||
|---|---|---|---|---|---|---|---|---|---|
 complex between tap uba domain and fxfg nucleoporin peptide | |||||||||
| Identifiers | |||||||||
| Symbol | TAP_C | ||||||||
| Pfam | PF03943 | ||||||||
| Pfam clan | CL0214 | ||||||||
| InterPro | IPR005637 | ||||||||
| SCOP2 | 1go5 / SCOPe / SUPFAM | ||||||||
| |||||||||
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.
A nuclear pore is a channel as part of the nuclear pore complex (NPC), a large protein complex found in the nuclear envelope in eukaryotic cells, enveloping the cell nucleus containing DNA, which facilitates the selective membrane transport of various molecules across the membrane.
Transporter associated with antigen processing (TAP) protein complex belongs to the ATP-binding-cassette transporter family. It delivers cytosolic peptides into the endoplasmic reticulum (ER), where they bind to nascent MHC class I molecules.
Nuclear pore glycoprotein p62 is a protein complex associated with the nuclear envelope. The p62 protein remains associated with the nuclear pore complex-lamina fraction. p62 is synthesized as a soluble cytoplasmic precursor of 61 kDa followed by modification that involve addition of N-acetylglucosamine residues, followed by association with other complex proteins. In humans it is encoded by the NUP62 gene.
Importin subunit beta-1 is a protein that in humans is encoded by the KPNB1 gene.
Nuclear pore complex protein Nup98-Nup96 is a protein that in humans is encoded by the NUP98 gene.
RNA-binding protein 8A is a protein that in humans is encoded by the RBM8A gene.
Nucleoporin 153 (Nup153) is a protein which in humans is encoded by the NUP153 gene. It is an essential component of the basket of nuclear pore complexes (NPCs) in vertebrates, and required for the anchoring of NPCs. It also acts as the docking site of an importing karyopherin. On the cytoplasmic side of the NPC, Nup358 fulfills an analogous role.
Transportin-1 is a protein that in humans is encoded by the TNPO1 gene.
Nucleoporin 214 (Nup2014) is a protein that in humans is encoded by the NUP214 gene.
RNA-binding protein with serine-rich domain 1 is a protein that in humans is encoded by the RNPS1 gene.
Arf-GAP domain and FG repeat-containing protein 1 is a protein that in humans is encoded by the AGFG1 gene.
mRNA export factor is a protein that in humans is encoded by the RAE1 gene.
Aly/REF export factor, also known as THO complex subunit 4 is a protein that in humans is encoded by the ALYREF gene.
Protein mago nashi homolog is a protein that in humans is encoded by the MAGOH gene.
NTF2-related export protein 1 is a protein that in humans is encoded by the NXT1 gene.
Nucleoporin-like 2 is a protein that in humans is encoded by the NUPL2 gene.
Transportin-2 is a protein that in humans is encoded by the TNPO2 gene.
Nuclear RNA export factor 2 is a protein that in humans is encoded by the NXF2 gene.
An exon junction complex (EJC) is a protein complex which forms on a pre-messenger RNA strand at the junction of two exons which have been joined together during RNA splicing. The EJC has major influences on translation, surveillance, localization of the spliced mRNA, and m6A methylation. It is first deposited onto mRNA during splicing and is then transported into the cytoplasm. There it plays a major role in post-transcriptional regulation of mRNA. It is believed that exon junction complexes provide a position-specific memory of the splicing event. The EJC consists of a stable heterotetramer core, which serves as a binding platform for other factors necessary for the mRNA pathway. The core of the EJC contains the protein eukaryotic initiation factor 4A-III bound to an adenosine triphosphate (ATP) analog, as well as the additional proteins Magoh and Y14. The binding of these proteins to nuclear speckled domains has been measured recently and it may be regulated by PI3K/AKT/mTOR signaling pathways. In order for the binding of the complex to the mRNA to occur, the eIF4AIII factor is inhibited, stopping the hydrolysis of ATP. This recognizes EJC as an ATP dependent complex. EJC also interacts with a large number of additional proteins; most notably SR proteins. These interactions are suggested to be important for mRNA compaction. The role of EJC in mRNA export is controversial.
The TREX (TRanscription-EXport) complex is a conserved eukaryotic multi-protein complex that couples mRNA transcription and nuclear export. The TREX complex travels across transcribed genes with RNA polymerase II. TREX binds mRNA and recruits transport proteins NXF1 and NXT1, which shuttle the mRNA out of the nucleus. The TREX complex plays an important role in genome stability and neurodegenerative diseases.
PDB gallery | |
|---|---|
|
