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Sunday 12 June 2005

Definition: GDP dissociation inhibitors (GDIs) are proteins that regulate the GDP-GTP exchange reaction of members of the rab family (RABS), small GTP-binding proteins of the ras superfamily, that are involved in vesicular trafficking of molecules between cellular organelles.


The GDP dissociation inhibitors (GDIs) are pivotal regulators of Rho GTPase function. GDIs control the access of Rho GTPases to regulatory guanine nucleotide exchange factors and GTPase-activating proteins, to effector targets and to membranes where such effectors reside. Rho GTPase-GDI complexes are regulated by various proteins, lipids and enzymes that exert GDI displacement activity.

The rab proteins (RABs) undergo activation upon GTP binding, and GTP hydrolysis to GDP inactivates the protein. GDIs slow the rate of dissociation of GDP from rab proteins and release GDP from membrane-bound RABs.

See also



- Dermardirossian C, Bokoch GM. GDIs: central regulatory molecules in Rho GTPase activation. Trends Cell Biol. 2005 May 23 PMID: 15921909