Nuclear RNA export factor 1, also known as NXF1 or TAP, is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...

which in humans is encoded by the ''NXF1''

gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...

Function

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 NTF2-related export protein 1 is a protein that in humans is encoded by the ''NXT1'' gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation' ...

), and a

ubiquitin Ubiquitin is a small (8.6 kDa) regulatory protein found in most tissues of eukaryotic organisms, i.e., it is found ''ubiquitously''. It was discovered in 1975 by Gideon Goldstein and further characterized throughout the late 1970s and 1980s. Fo ...

-associated domain that mediates interactions with

nucleoporin Nucleoporins are a family of proteins which are the constituent building blocks of the nuclear pore complex (NPC). The nuclear pore complex is a massive structure embedded in the nuclear envelope at sites where the inner and outer nuclear membr ...

s. 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 Nucleus ( : nuclei) is a Latin word for the seed inside a fruit. It most often refers to: *Atomic nucleus, the very dense central region of an atom *Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA Nucle ...

and the

cytoplasm In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. The ...

and binds in vivo to poly(A)+ RNA. It is the vertebrate homologue of the yeast protein Mex67p. The encoded protein overcomes the mRNA export block caused by the presence of saturating amounts of CTE (constitutive transport element) RNA of type D

retrovirus A retrovirus is a type of virus that inserts a DNA copy of its RNA genome into the DNA of a host cell that it invades, thus changing the genome of that cell. Once inside the host cell's cytoplasm, the virus uses its own reverse transcriptase ...

es. 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.

Interactions

NXF1 has been shown to

interact Advocates for Informed Choice, dba interACT or interACT Advocates for Intersex Youth, is a 501(c)(3) nonprofit organization using innovative strategies to advocate for the legal and human rights of children with intersex traits. The organizati ...

with

TNPO2 Transportin-2 is a protein that in humans is encoded by the ''TNPO2'' gene. Interactions TNPO2 has been shown to interact with NXF1, NUP98 and Ran (biology) Ran (RAs-related Nuclear protein) also known as GTP-binding nuclear protein Ran is a ...

MAGOH Protein mago nashi homolog is a protein that in humans is encoded by the ''MAGOH'' gene. Drosophila that have mutations in their mago nashi (grandchildless) gene produce progeny with defects in germplasm assembly and germline development. This ge ...

U2 small nuclear RNA auxiliary factor 1 Splicing factor U2AF 35 kDa subunit is a protein that in humans is encoded by the ''U2AF1'' gene. Function This gene belongs to the splicing factor SR family of genes . U2AF1 is a subunit of the U2 Auxiliary Factor complex alongside a larger ...

DHX9 ATP-dependent RNA helicase A (RHA; also known as DHX9, LKP, and NDHI) is an enzyme that in humans is encoded by the ''DHX9'' gene. Function DEAD/DEAH box helicases are proteins, and are putative RNA helicases. They are implicated in a number o ...

HuD Hud or HUD may refer to: Entertainment * ''Hud'' (1963 film), a 1963 film starring Paul Newman * ''Hud'' (1986 film), a 1986 Norwegian film * ''HUD'' (TV program), or ''Heads Up Daily'', a Canadian e-sports television program Places * Hud, Fa ...

and

NUP214 Nucleoporin 214 (Nup2014) is a protein that in humans is encoded by the ''NUP214'' gene. Function The nuclear pore complex is a massive structure that extends across the nuclear envelope, forming a gateway that regulates the flow of macromole ...

Tap protein

In molecular biology, another name for the protein NXF1 is TAP. In particular this entry focuses on the

C-terminal The C-terminus (also known as the carboxyl-terminus, carboxy-terminus, C-terminal tail, C-terminal end, or COOH-terminus) is the end of an amino acid chain (protein or polypeptide), terminated by a free carboxyl group (-COOH). When the protein is ...

domain, which also contains the UBA (protein domain). This entry contains the NXF family of shuttling

transport Transport (in British English), or transportation (in American English), is the intentional movement of humans, animals, and goods from one location to another. Modes of transport include air, land (rail and road), water, cable, pipeline, an ...

receptor Receptor may refer to: * Sensory receptor, in physiology, any structure which, on receiving environmental stimuli, produces an informative nerve impulse *Receptor (biochemistry), in biochemistry, a protein molecule that receives and responds to a ...

s for

nuclear Nuclear may refer to: Physics Relating to the nucleus of the atom: * Nuclear engineering *Nuclear physics *Nuclear power *Nuclear reactor *Nuclear weapon *Nuclear medicine *Radiation therapy *Nuclear warfare Mathematics *Nuclear space *Nuclear ...

export of mRNA, which include: *

vertebrate Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, ...

mRNA export factor TAP or nuclear RNA export factor 1 (NXF1). * ''Caenorhabditis elegans'' nuclear RNA export factor 1 (nxf-1). *

yeast Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are estimated to constitut ...

mRNA export factor MEX67. Members of the NXF family have a modular

structure A structure is an arrangement and organization of interrelated elements in a material object or system, or the object or system so organized. Material structures include man-made objects such as buildings and machines and natural objects such as ...

. A nuclear localization

sequence In mathematics, a sequence is an enumerated collection of objects in which repetitions are allowed and order matters. Like a set, it contains members (also called ''elements'', or ''terms''). The number of elements (possibly infinite) is calle ...

and a noncanonical RNA recognition motif (RRM) (se
PROSITEDOC
followed by four LRR repeats are located in its N-terminal half. The C-terminal half contains a NTF2

domain Domain may refer to: Mathematics *Domain of a function, the set of input values for which the (total) function is defined **Domain of definition of a partial function **Natural domain of a partial function **Domain of holomorphy of a function * Do ...

(see ref="http://expasy.org/prosite/PDOC50177 PROSITEDOC followed by a second domain, TAP-C. The TAP-C domain is important for binding to FG repeat-containing

nuclear pore A nuclear pore is a part of a large complex of proteins, known as a nuclear pore complex that spans the nuclear envelope, which is the double membrane surrounding the eukaryotic cell nucleus. There are approximately 1,000 nuclear pore complexes ...

s (FG-nucleoporins) and is sufficient to mediate nuclear shuttling. The Tap-C domain is made of four

alpha helices The alpha helix (α-helix) is a common motif in the secondary structure of proteins and is a right hand-helix conformation in which every backbone N−H group hydrogen bonds to the backbone C=O group of the amino acid located four residues ear ...

packed against each other. The arrangement of

helices A helix () is a shape like a corkscrew or spiral staircase. It is a type of smooth space curve with tangent lines at a constant angle to a fixed axis. Helices are important in biology, as the DNA molecule is formed as two intertwined 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.

Function

Nuclear export of mRNAs is mediated by the Tap protein.

Structure

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.

References

External links

PDBe-KB
provides an overview of all the structure information available in the PDB for Human Nuclear RNA export factor 1 (NXF1) {{PDB_Gallery, geneid=10482