Guanine nucleotide exchange factors (GEFs) are proteins or protein domains involved in the activation of small GTPases. Small GTPases act as molecular switches in intracellular signaling pathways and have many downstream targets.

Feb 1, 2005 · Guanine nucleotide-exchange factors (GEFs) are directly responsible for the activation of Rho-family GTPases in response to diverse extracellular stimuli, and ultimately regulate numerous...

Jun 1, 2007 · GEFs and GAPs are multidomain proteins that are regulated by extracellular signals and localized cues that control cellular events in time and space. Recent evidence suggests that these proteins may be potential therapeutic targets for developing drugs to treat various diseases, including cancer.

The experimental analysis of GEFs as enzymes requires only that the substrates, GTP and G•GDP, and the products, GDP and G•GTP, be stable and quantifiable. An additional advantage is that enzyme parameters are directly related to the generation of G•GTP, the physiologically relevant product.

Activation of RhoA is mediated by guanine nucleotide exchange factors (GEFs), a diverse family of enzymes that are controlled by multiple signaling pathways regulating actin cytoskeleton and cell migration. GEFs can be regulated by different mechanisms.

Apr 1, 2001 · By catalyzing the release of GDP from, and the subsequent uptake of GTP by, G proteins, GEFs enable G proteins to activate downstream effectors such as kinases, adenylate cyclases and ion channels. GEFs serve as the initial point of control for most G …

Rho guanine nucleotide exchange factors (GEFs) represent the major class of activating enzymes of Rho GTPases by serving to relay a variety of signals to catalyze GDP/GTP exchange of specific Rho GTPases. To date, >80 RhoGEFs have been discovered that regulate the activities of over a dozen Rho GTPases in mammals (5).

Mar 24, 2025 · When the GEF enzyme stimulates Rho, it causes the protein to switch from an essentially free-floating state to a state that binds the protein to the cell's membrane. In this membrane-bound state ...

Here, we review the roles of GEF-H1 in epithelial barrier permeability, cell motility and polarization, dendritic spine morphology, antigen presentation, leukemic cell differentiation, cell cycle regulation, and cancer.

Dec 21, 2007 · One such autoinhibited Rho GEF is p63RhoGEF (8–10), a RhoA-specific enzyme predominantly expressed in the heart and brain . p63RhoGEF is directly activated by members of the Gα q subfamily of heterotrimeric guanine nucleotide–binding proteins (G proteins) (9, 10) and thus is regulated by G protein–coupled receptors (GPCRs).