RanGAP 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 ...

involved in the transport of other proteins from the

cytosol The cytosol, also known as cytoplasmic matrix or groundplasm, is one of the liquids found inside cells (intracellular fluid (ICF)). It is separated into compartments by membranes. For example, the mitochondrial matrix separates the mitochondri ...

to 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 ...

eukaryotic Eukaryotes () are organisms whose cells have a nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the three domains of life. Bacte ...

cells. In model species such as the yeast ''

Saccharomyces cerevisiae ''Saccharomyces cerevisiae'' () (brewer's yeast or baker's yeast) is a species of yeast (single-celled fungus microorganisms). The species has been instrumental in winemaking, baking, and brewing since ancient times. It is believed to have been o ...

'', the primate ''

Homo sapiens Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...

'' (See

RANGAP1 Ran GTPase-activating protein 1 is an enzyme that in humans is encoded by the ''RANGAP1'' gene. Function RanGAP1, is a homodimeric 65-kD polypeptide that specifically induces the GTPase activity of RAN, but not of RAS by over 1,000-fold. RanG ...

) and the plant ''

Arabidopsis thaliana ''Arabidopsis thaliana'', the thale cress, mouse-ear cress or arabidopsis, is a small flowering plant native to Eurasia and Africa. ''A. thaliana'' is considered a weed; it is found along the shoulders of roads and in disturbed land. A winter a ...

,'' it acts as a

GTPase-activating protein GTPase-activating proteins or GTPase-accelerating proteins (GAPs) are a family of regulatory proteins whose members can bind to activated G proteins and stimulate their GTPase activity, with the result of terminating the signaling event. GAPs are a ...

, catalysing the conversion of cytosolically-bound

RanGTP Ran (RAs-related Nuclear protein) 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 ...

Ran Ran, RaN and ran may refer to: Arts and entertainment * ''Ran'' (film), a 1985 film directed by Akira Kurosawa * "Ran" (song), a 2013 Japanese song by Luna Sea * '' Ran Online'', a 2004 MMORPG (massively multiplayer online role playing game) * ...

GDP Gross domestic product (GDP) is a monetary measure of the market value of all the final goods and services produced and sold (not resold) in a specific time period by countries. Due to its complex and subjective nature this measure is often ...

. It has the opposite function of the

RCC1 Regulator of chromosome condensation 1, also known as RCC1, Ran guanine nucleotide exchange factor and RanGEF, is the name for a human gene and protein. RCC1 also functions as a guanine nucleotide exchange factor for Ran GTPase. Interactions R ...

, a nuclear-located protein that converts RanGDP to RanGTP. Together, RanGAP and RCC1 maintain what is known as the ran gradient, where RanGDP is in higher concentrations in the cytosol, while RanGTP is in higher concentrations in the nucleus. It is this ran gradient which provides the energy necessary for the transport of proteins into and out of the nucleus by

karyopherin Karyopherins are proteins involved in transporting molecules between the cytoplasm and the nucleus of a eukaryotic cell. The inside of the nucleus is called the karyoplasm (or nucleoplasm). Generally, karyopherin-mediated transport occurs through ...

proteins.

Location in cell

mammalian Mammals () are a group of vertebrate animals constituting the class (biology), class Mammalia (), characterized by the presence of mammary glands which in Female#Mammalian female, females produce milk for feeding (nursing) their young, a ...

and plant cells, RanGAP is located at 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 membrane ...

during

interphase Interphase is the portion of the cell cycle that is not accompanied by visible changes under the microscope, and includes the G1, S and G2 phases. During interphase, the cell grows (G1), replicates its DNA (S) and prepares for mitosis (G2). A c ...

. Animal RanGAP is bound to the nuclear pore component

RANBP2 RAN binding protein 2 (RANBP2) is protein which in humans is encoded by the ''RANBP2'' gene. It is also known as nucleoporin 358 (Nup358) since it is a member nucleoporin family that makes up the nuclear pore complex. RanBP2 has a mass of 358 kDa. ...

(Nup358). Plant RanGAP proteins do not contain the

protein domain In molecular biology, a protein domain is a region of a protein's polypeptide chain that is self-stabilizing and that folds independently from the rest. Each domain forms a compact folded three-dimensional structure. Many proteins consist of s ...

necessary for association with Nup358 but are targeted to the nuclear rim by the plant-specific

WPP domain The WPP domain is a protein domain thought to be exclusively found in plants, first identified in 2000. The domain is about 90 amino acid residues long. The domain is known to direct RanGAP to the nuclear envelope. Non-RanGAP nuclear envelope pro ...

. In contrast to plant and animal cells, yeast RanGAP is located in the cytosol.

RanGAP and the origin of eukaryotes

Together with

and components of the

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 ...

, RanGAP has been suggested to have evolved at the origin of

eukaryotes Eukaryotes () are organisms whose cells have a nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the three domains of life. Bacte ...

.{{cite journal , author=Cavalier-Smith T , title=Origin of the cell nucleus, mitosis and sex: roles of intracellular coevolution , journal=

Biology Direct ''Biology Direct'' is an online open access scientific journal that publishes original, peer-reviewed research papers, reviews, hypotheses, comments and discovery notes in biology. The journal is published by BioMed Central. The journal follows a ...

, volume=5 , pages=7 , year=2010 , pmid=20132544 , pmc=2837639 , doi=10.1186/1745-6150-5-7

References

Transport proteins