RasGAP

GTPase-activator protein for Ras-like GTPases
RasGAP
SMART accession number:SM00323
Description: All alpha-helical domain that accelerates the GTPase activity of Ras, thereby "switching" it into an "off" position. Improved domain limits from structure.
Interpro abstract (IPR001936):

Ras proteins are membrane-associated molecular switches that bind GTP and GDP and slowly hydrolyze GTP to GDP [(PUBMED:1898771)]. This intrinsic GTPase activity of ras is stimulated by a family of proteins collectively known as 'GAP' or GTPase-activating proteins [(PUBMED:1883874), (PUBMED:7945277)]. As it is the GTP bound form of ras which is active, these proteins are said to be down-regulators of ras.

The Ras GTPase-activating proteins are quite large (from 765 residues for sar1 to 3079 residues for IRA2) but share only a limited (about 250 residues) region of sequence similarity, referred to as the 'catalytic domain' or rasGAP domain.

Note: There are distinctly different GAPs for the rap and rho/rac subfamilies of ras-like proteins (reviewed in reference [(PUBMED:8259209)]) that do not share sequence similarity with ras GAPs.

GO process:regulation of small GTPase mediated signal transduction (GO:0051056)
GO component:intracellular (GO:0005622)
GO function:GTPase activator activity (GO:0005096)
Family alignment:
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There are 746 RasGAP domains in 746 proteins in SMART's nrdb database.

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