Ran GTPase-activating protein 1 is an
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecule ...
that in humans is encoded by the ''RANGAP1''
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 b ...
.
Function
RanGAP1, is a
homodimeric
In biochemistry, a protein dimer is a macromolecular complex formed by two protein monomers, or single proteins, which are usually non-covalently bound. Many macromolecules, such as proteins or nucleic acids, form dimers. The word ''dimer'' has ...
65-kD polypeptide that specifically induces the
GTPase
GTPases are a large family of hydrolase enzymes that bind to the nucleotide guanosine triphosphate (GTP) and hydrolyze it to guanosine diphosphate (GDP). The GTP binding and hydrolysis takes place in the highly conserved P-loop "G domain", a ...
activity of
RAN, but not of
RAS by over 1,000-fold. RanGAP1 is the immediate antagonist of
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 regulator molecule that keeps RAN in the active,
GTP-bound state. The RANGAP1 gene encodes a 587-amino acid polypeptide. The sequence is unrelated to that of
GTPase activators for other
RAS-related proteins, but is 88% identical to Rangap1 (Fug1), the murine homolog of yeast Rna1p. RanGAP1 and RCC1 control RAN-dependent transport between the nucleus and cytoplasm. RanGAP1 is a key regulator of the
RAN GTP/GDP cycle.
Interactions
RanGAP1 is a trafficking protein which helps transport other proteins from the cytoplasm to the nucleus. Small ubiquitin-related modifier needs to be associated with it before it can be localized at the nuclear pore.
RANGAP1 has been shown to
interact
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with:
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Ran,
and
*
UBE2I
SUMO-conjugating enzyme UBC9 is an enzyme that in humans is encoded by the ''UBE2I'' gene. It is also sometimes referred to as "ubiquitin conjugating enzyme E2I" or "ubiquitin carrier protein 9", even though these names do not accurately describe ...
.
References
Further reading
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{{PDB Gallery, geneid=5905