Enables small GTPase binding activity. Involved in several processes, including axon extension; late endosome to lysosome transport; and negative regulation of GTP binding activity. Located in several cellular components, including extracellular space; neuron projection; and perikaryon. Is expressed in several structures, including adipose tissue; alimentary system; nervous system; reproductive system; and sensory organ. Used to study autoimmune disease. Human ortholog(s) of this gene implicated in frontotemporal dementia and/or amyotrophic lateral sclerosis-1. Orthologous to human C9orf72 (C9orf72-SMCR8 complex subunit). [provided by Alliance of Genome Resources, Apr 2022]