RHO GTPase RHOU (Wrch-1) possesses a high intrinsic guanine nucleotide exchange activity and is constitutively present in the active GTP-bound state in the absence of guanine nucleotide exchange factors (GEFs) (Shutes et al. 2004, Saras et al. 2004). RHOU does not possess a GTPase activity (Saras et al. 2004). RHOU has been reported to interact with some GTPase activator proteins (GAPs) (Bagci et al. 2020), which may serve as effectors that enable cross-talk with other RHO GTPases.
For review, please refer to Faure and Fort 2015, and Hodge and Ridley 2020.