Rho protein GDP-dissociation inhibitor (IPR000406)

Short name: Rho_GDI

Overlapping homologous superfamilies

Family relationships



The GDP dissociation inhibitor for rho proteins, rho GDI, regulates GDP/GTP exchange by inhibiting the dissociation of GDP from them. 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 [PMID: 8223583]. 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 [PMID: 8796870]. Dissociation of these proteins might be mediated by the release of lipids (e.g., arachidonate and phosphatidate) from membranes through the action of phospholipases [PMID: 8796870]. The lipids may then compete with the lipid tail on p21rac for the hydrophobic pocket on GDI.

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0005094 Rho GDP-dissociation inhibitor activity

Cellular Component

GO:0005737 cytoplasm

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.