| Literature References | 1. FUKUMOTO, Y., KAIBUCHI, K., HORI, Y., FUJIOKA, H., ARAKI, S., UEDA, T.,
KIKUCHI, A. AND TAKAI, Y.
Molecular cloning and characterization of a novel type of regulatory
protein (GDI) for the rho proteins, ras p21-like small GTP-binding proteins.
ONCOGENE 5 1321-1328 (1990).
2. PICK, E., GORZALCZANY, Y. AND ENGEL, S.
Role of the rac1 p21-GDP-dissociation inhibitor for rho heterodimer in the
activation of the superoxide-forming NADPH oxidase of macrophages.
EUR.J.BIOCHEMISTRY 217 441-455 (1993).
3. SEGAL, A.W.
The NADPH oxidase and chronic granulomatous disease.
MOL.MED.TODAY 2(3) 129-135 (1996).
|
| Documentation | The GDP dissociation inhibitor for rho proteins, rho GDI, regulates GDP/GTP
exchange. The protein contains 204 amino acids, with a calculated Mr value
of 23,421. Hydropathy analysis shows it to be largely hydrophilic, with a
single hydrophobic region. Results of database searches suggest rho GDI is
a novel protein, currently with no known homologue.
The protein plays an important role in the activation of the superoxide
(O2-)-generating NADPH oxidase of phagocytes. This process requires the
interaction of membrane-associated cytochrome b559 with 3 cytosolic
components: p47-phox, p67-phox and a heterodimer of the small G protein
p21rac1 and rho GDI [2]. The association of p21rac and GDI inhibits
dissociation of GDP from p21rac, thereby maintaining it in an inactive form.
The proteins are attached via a lipid tail on p21rac that binds to the
hydrophobic region of GDI [3]. Dissociation of these proteins might be
mediated by the release of lipids (e.g., arachidonate and phosphatidate)
from membranes through the action of phospholipases [3]. The lipids may then
compete with the lipid tail on p21rac for the hydrophobic pocket on GDI.
RHOGDI is a 6-element fingerprint that provides a signature for rho protein
GDP dissociation inhibitors. The fingerprint was derived from an initial
alignment of 3 sequences: the motifs were drawn from short conserved
regions spanning the full alignment length. Two iterations on OWL27.0 were
required to reach convergence, at which point a true set comprising 8
sequences was identified. Three partial matches were also found, all of
which are rhoGDI fragments.
An update on SPTR37_9f identified a true set of 6 sequences, and 3
partial matches.
|