In vitro fluorescence assay to measure GDP/GTP exchange of guanine nucleotide exchange factors of Rho family GTPases.

Guanine nucleotide exchange factors (GEFs) are enzymes that promote the activation of GTPases through GTP loading. Whole exome sequencing has identified rare variants in GEFs that are associated with disease, demonstrating that GEFs play critical roles in human development. However, the consequences of these rare variants can only be understood through measuring their effects on cellular activity.