Quantitative Analysis of Prenylated RhoA Interaction with Its Chaperone, RhoGDI

A1 Journal article (refereed)


Internal Authors/Editors


Publication Details

List of Authors: Tnimov Z, Guo Z, Gambin Y, Nguyen UTT, Wu YW, Abankwa D, Stigter A, Collins BM, Waldmann H, Goody RS, Alexandrov K
Publisher: AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
Publication year: 2012
Journal: Journal of Biological Chemistry
Journal acronym: J BIOL CHEM
Volume number: 287
Issue number: 32
Start page: 26549
End page: 26562
Number of pages: 14
ISSN: 0021-9258


Abstract

Small GTPases of the Rho family regulate cytoskeleton remodeling, cell polarity, and transcription, as well as the cell cycle, in eukaryotic cells. Membrane delivery and recycling of the Rho GTPases is mediated by Rho GDP dissociation inhibitor (RhoGDI), which forms a stable complex with prenylated Rho GTPases. We analyzed the interaction of RhoGDI with the active and inactive forms of prenylated and unprenylated RhoA. We demonstrate that RhoGDI binds the prenylated form of RhoA center dot GDP with unexpectedly high affinity (K-d = 5 pM). The very long half-life of the complex is reduced 25-fold on RhoA activation, with a concomitant reduction in affinity (K-d = 3 nM). The 2.8-angstrom structure of the RhoA center dot guanosine 5'-[beta,gamma-imido] triphosphate (GMPPNP)center dot RhoGDI complex demonstrated that complex formation forces the activated RhoA into a GDP-bound conformation in the absence of nucleotide hydrolysis. We demonstrate that membrane extraction of Rho GTPase by RhoGDI is a thermodynamically favored passive process that operates through a series of progressively tighter intermediates, much like the one that is mediated by RabGDI.

Last updated on 2019-23-09 at 05:58