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 (NPCs) in the nuclear envelope of a vertebrate cell, but this number varies depending on cell type and the stage in the life cycle. The human nuclear pore complex (hNPC) is a 110 megadalton (MDa) structure. The proteins that make up the nuclear pore complex are known as nucleoporins; each NPC contains at least 456 individual protein molecules and is composed of 34 distinct nucleoporin proteins. About half of the nucleoporins typically contain solenoid protein domains—either an alpha solenoid or a beta-propeller fold, or in some cases both as separate structural domains. The other half show structural characteristics typical of "natively unfolded" or intrinsically disordered proteins, i.e. they are highly flexible proteins that lack ordered tertiary structure. These disordered proteins are the FG nucleoporins, so called because their amino-acid sequence contains many phenylalanine—glycine repeats.
Ran also known as GTP-binding nuclear protein Ran is a protein that in humans is encoded by the RAN gene. Ran is a small 25 kDa protein that is involved in transport into and out of the cell nucleus during interphase and also involved in mitosis. It is a member of the Ras superfamily.
Nucleoporin p62 (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.
Nuclear pore complex protein Nup98-Nup96 is a protein that in humans is encoded by the NUP98 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.
Tristetraprolin (TTP), also known as zinc finger protein 36 homolog (ZFP36), is a protein that in humans, mice and rats is encoded by the ZFP36 gene. It is a member of the TIS11 family, along with butyrate response factors 1 and 2.
Cell cycle checkpoint protein RAD1 is a protein that in humans is encoded by the RAD1 gene.
Nucleoporin 214 (Nup2014) is a protein that in humans is encoded by the NUP214 gene.
Nucleoporin 88 (Nup88) is a protein that in humans is encoded by the NUP88 gene.
Pre-mRNA-processing factor 6 is a protein that in humans is encoded by the PRPF6 gene.
Nucleoporin 50 (Nup50) is a protein that in humans is encoded by the NUP50 gene.
Myosin-Ic is a protein that in humans is encoded by the MYO1C gene.
Nucleoporin 160 (Nup160) is a protein that in humans is encoded by the NUP160 gene.
Nucleoporin GLE1 is a protein that in humans is encoded by the GLE1 gene on chromosome 9.
Nucleoporin 155 (Nup155) is a protein that in humans is encoded by the NUP155 gene.
Exportin-T is a protein that in humans is encoded by the XPOT gene.
ATP-dependent RNA helicase DDX19B is an enzyme that in humans is encoded by the DDX19B gene.
Nucleoporin 93 (Nup93) is a protein that in humans is encoded by the NUP93 gene.
Nucleoporin 35 (Nup35) is a protein that in humans is encoded by the NUP35 gene.
Gene gating is a phenomenon by which transcriptionally active genes are brought next to nuclear pore complexes (NPCs) so that nascent transcripts can quickly form mature mRNA associated with export factors. Gene gating was first hypothesised by Günter Blobel in 1985. It has been shown to occur in Saccharomyces cerevisiae, Caenorhabditis elegans, Drosophila melanogaster as well as mammalian model systems.
