Nuclear pore glycoprotein-210 (gp210) is an essential trafficking regulator in the eukaryotic

nuclear pore complex The nuclear pore complex (NPC), is a large protein complex giving rise to the nuclear pore. A great number of nuclear pores are studded throughout the nuclear envelope that surrounds the eukaryote cell nucleus. The pores enable the nuclear tra ...

. Gp-210 anchors the pore complex to the nuclear membrane. and protein tagging reveals its primarily located on the luminal side of double layer membrane at the pore. A single polypeptide motif of gp210 is responsible for sorting to nuclear membrane, and indicate the carboxyl tail of the protein is oriented toward the cytoplasmic side of the membrane.

Disassembly and Assembly

During

eukaryotic The eukaryotes ( ) constitute the Domain (biology), domain of Eukaryota or Eukarya, organisms whose Cell (biology), cells have a membrane-bound cell nucleus, nucleus. All animals, plants, Fungus, fungi, seaweeds, and many unicellular organisms ...

mitosis Mitosis () is a part of the cell cycle in eukaryote, eukaryotic cells in which replicated chromosomes are separated into two new Cell nucleus, nuclei. Cell division by mitosis is an equational division which gives rise to genetically identic ...

the

nuclear envelope The nuclear envelope, also known as the nuclear membrane, is made up of two lipid bilayer membranes that in eukaryotic cells surround the nucleus, which encloses the genetic material. The nuclear envelope consists of two lipid bilayer membran ...

disintegrates into vesicles dispersing nuclear lamina proteins and

es. Nup210 is specifically

phosphorylate In biochemistry, phosphorylation is described as the "transfer of a phosphate group" from a donor to an acceptor. A common phosphorylating agent (phosphate donor) is ATP and a common family of acceptor are alcohols: : This equation can be writt ...

d on the C-terminal (cytoplasmic) domain in mitosis at Ser1880 and is dispersed throughout the

endoplasmic reticulum The endoplasmic reticulum (ER) is a part of a transportation system of the eukaryote, eukaryotic cell, and has many other important functions such as protein folding. The word endoplasmic means "within the cytoplasm", and reticulum is Latin for ...

during mitosis as homodimers. Nuclear lamins begin to reassemble around chromosomes at the end of mitosis. Nup210 lags the reassembly process relative to other Nups. and while much of the assembly process can occur without it, the final assembly and dilation of the complexes require Nup210. The replacement of

serine Serine (symbol Ser or S) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α- amino group (which is in the protonated − form under biological conditions), a carboxyl group (which is in the deprotonated − ...

at position 1880 with a phosphorylated 'looking'

glutamate Glutamic acid (symbol Glu or E; known as glutamate in its anionic form) is an α-amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a Essential amino acid, non-essential nutrient for humans, meaning that ...

results in Nup210 complexes that fail to reassemble indicating that

dephosphorylation In biochemistry, dephosphorylation is the removal of a phosphate () group from an organic compound by hydrolysis. It is a reversible post-translational modification. Dephosphorylation and its counterpart, phosphorylation, activate and deactivate e ...

of Nup210 within the final phases of proper assembly is required.

Pathology

Recognized by anti-nuclear antibodies found in

primary biliary cirrhosis Primary biliary cholangitis (PBC), previously known as primary biliary cirrhosis, is an autoimmune disease of the liver. It results from a slow, progressive destruction of the small bile ducts of the liver, causing bile and other toxins to buil ...

(PBC) anti-Nup210 antibodies correlate with progression toward end stage liver disease. Nup210 is possibly a destructive autoimmune target of the disease. One idea for the loss of tolerance is the increased or abnormal expression of Nup210 in patients with PBC. Anti-mitochondrial, anti-centromere and anti-nup62 are also found in PBC.

References

{{DEFAULTSORT:Nucleoporin 210kda Autoantigens Glycoproteins Membrane proteins Nuclear pore complex