InterPro domain: IPR039360

Ras proteins are membrane-associated molecular switches that bind GTP and GDPand slowly hydrolyze GTP to GDP [ 1 ]. This intrinsic GTPase activity of Ras is regulated by a family of proteins collectively known as 'GAP' or GTPase-activating proteins [ 2 , 3 ]. RasGAP proteins are usually quite large (from 765 residues for sar1 to 3079residues for IRA2) but share only a limited (about 250 residues) region ofsequence similarity, referred to as the 'catalytic domain' or RasGAP domain.The most conserved region within this domain contains a 15 residue motif whichseems to be characteristic of this family of proteins [ 4 ].

Note: There are distinctly different GAPs for the Rap and Rho/Rac subfamilies of Ras-like proteins that do not share sequence similarity with Ras GAPs [ 4 ].

1. The GTPase superfamily: conserved structure and molecular mechanism. Nature 349, 117-27
2. sar1, a gene from Schizosaccharomyces pombe encoding a protein that regulates ras1. Cell Regul. 2, 453-65
3. Regulation of the Ras signalling network. Bioessays 16, 489-96
4. Proteins regulating Ras and its relatives. Nature 366, 643-54