|PROSITE documentation PDOC51715|
The P-loop (see <PDOC00017>) guanosine triphosphatases (GTPases) control a multitude of biological processes, ranging from cell division, cell cycling, and signal transduction, to ribosome assembly and protein synthesis. GTPases exert their control by interchanging between an inactive GDP-bound state and an active GTP-bound state, thereby acting as molecular switches. The common denominator of GTPases is the highly conserved guanine nucleotide-binding (G) domain that is responsible for binding and hydrolysis of guanine nucleotides.
The GB1/RHD3 GTPase family contains a large G domain (~230 amino acids). It is widespread in eukaryotes, but not detectable in bacteria or archaea. One conserved subfamily is typified by the Arabidopsis protein root hair defective 3 (RHD3), whose othologs are present in all crown group eukaryotes. The other subfamily is typified by the interferon γ-induced antiviral GB1 protein that is conserved in animals. The other GTPases of this subfamily are the brain finger proteins (BFPs), in which the GTPase domain is combined with an N-terminal RING finger domain (see <PDOC00449>), which implicates these proteins in ubiquitin-mediated signaling. Most members of this family have a large C-terminal, α-helical extension that probably participates in protein-protein interactions. The GB1/RHD3-type G domain has a low intrinsic affinity for nucleotide and often depends on nucleotide-dependent homodimerization to facilitate GTP hydrolysis [1,2,3,4,5,6].
The large GB1/RHD3-type G domain consists of a six-stranded β-sheet surrounded by eight helices (see <PDB:1DG3>). It contains the conserved sequence elements of GTP-binding proteins with modifications [2,4,6].
The profile we developed covers the entire GB1/RHD3-type G domain.Last update:
April 2014 / First entry.
PROSITE method (with tools and information) covered by this documentation:
|1||Authors||Leipe D.D. Wolf Y.I. Koonin E.V. Aravind L.|
|Title||Classification and evolution of P-loop GTPases and related ATPases.|
|Source||J. Mol. Biol. 317:41-72(2002).|
|2||Authors||Prakash B. Praefcke G.J.K. Renault L. Wittinghofer A. Herrmann C.|
|Title||Structure of human guanylate-binding protein 1 representing a unique class of GTP-binding proteins.|
|3||Authors||Prakash B. Renault L. Praefcke G.J.K. Herrmann C. Wittinghofer A.|
|Title||Triphosphate structure of guanylate-binding protein 1 and implications for nucleotide binding and GTPase mechanism.|
|Source||EMBO J. 19:4555-4564(2000).|
|4||Authors||Ghosh A. Praefcke G.J.K. Renault L. Wittinghofer A. Herrmann C.|
|Title||How guanylate-binding proteins achieve assembly-stimulated processive cleavage of GTP to GMP.|
|5||Authors||Stefano G. Renna L. Moss T. McNew J.A. Brandizzi F.|
|Title||In Arabidopsis, the spatial and dynamic organization of the endoplasmic reticulum and Golgi apparatus is influenced by the integrity of the C-terminal domain of RHD3, a non-essential GTPase.|
|Source||Plant J. 69:957-966(2012).|
|6||Authors||Byrnes L.J. Sondermann H.|
|Title||Structural basis for the nucleotide-dependent dimerization of the large G protein atlastin-1/SPG3A.|
|Source||Proc. Natl. Acad. Sci. U.S.A. 108:2216-2221(2011).|