The Rho family of small GTPases act as molecular switches to control a wide range of cellular processes. Guanine nucleotide exchange factors (GEFs), like GEFT, activate Rho GTPases by accelerating GDP/GTP exchange.The Rho family of small GTPases act as molecular switches to control a wide range of cellular processes. Guanine nucleotide exchange factors (GEFs), like GEFT, activate Rho GTPases by accelerating GDP/GTP exchange (Souchet et al., 2002 [PubMed 11861769]).[supplied by OMIM].