Enables small GTPase binding activity. Predicted to be involved in negative regulation of neuron projection development and retrograde transport, endosome to Golgi. Located in Golgi apparatus. Human ortholog(s) of this gene implicated in developmental and epileptic encephalopathy 49. Orthologous to human DENND5A (DENN domain containing 5A). [provided by Alliance of Genome Resources, Apr 2022]