Guanine nucleotide exchange factors (GEFs) catalyze exchange of GDP for GTP by stabilizing the nucleotide-free state of the small GTPases through their Dbl homology/pleckstrin homology (DH·PH) domains. Unconventionally, PDZ-RhoGEF (PRG), a member of the RGS-RhoGEFs, binds tightly to both nucleotide-free and activated RhoA (RhoA·GTP). We have characterized the interaction between PRG and activated RhoA and determined the structure of the PRG-DH·PH-RhoA·GTPγS (guanosine 5′-O-[γ-thio] triphosphate) complex. The interface bears striking similarity to a GTPase-effector interface and involves the switch regions in RhoA and a hydrophobic patch in PRG-PH that is conserved among all Lbc RhoGEFs. The two surfaces that bind activated and nucleotide-free RhoA on PRGD-H ·PH do not overlap, and a ternary complex of PRG-DH·PH bound to both forms of RhoA can be isolated by size-exclusion chromatography. This novel interaction between activated RhoA and PH could play a key role in regulation of RhoGEF activity in vivo. © 2010 by The American Society for Biochemistry and Molecular Biology, Inc.
CITATION STYLE
Chen, Z., Medina, F., Liu, M. Y., Thomas, C., Sprang, S. R., & Sternweis, P. C. (2010). Activated RhoA binds to the Pleckstrin Homology (PH) domain of PDZ-RhoGEF, a potential site for autoregulation. Journal of Biological Chemistry, 285(27), 21070–21081. https://doi.org/10.1074/jbc.M110.122549
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