The Rho GTPase family forms part of the Ras superfamily and consists, in humans, of 20 members, which can be classified into eight subgroups.  Rho GTPases are best known for their roles in regulating cytoskeletal rearrangements, cell motility, cell polarity, axon guidance, vesicle trafficking and the cell cycle. Alterations in Rho GTPase signalling contribute to malignant transformation, neurological abnormalities and immunological diseases. Most Rho GTPases cycle between an active GTP bound conformation and an inactive GDP-bound conformation. This cycling is regulated by three types of protein, Guanine nucleotide exchange factors (GEFs) catalyse the exchange of GDP for GTP, thereby activating the GTPase4, whereas GTPase-activating proteins (GAPs) increase the intrinsic GTP hydrolysis rate of the GTPase, thereby inactivating it. Guanine nucleotide dissociation inhibitors (GDIs) sequester the GDP-bound form of some GTPases in the cytosol and prevent them from localizing to membranes or being activated by GEFs. Rho GTPases are rapidly activated by various cell-surface receptors, including integrins, cadherins, cytokine receptors, Tyr kinase receptors and G protein-coupled receptors.


1.Hodge RG, et al. Nat Rev Mol Cell Biol. 2016;17(8):496–510.