Enables GTPase binding activity. Involved in several processes, including cellular response to hydrogen peroxide; positive regulation of cardiac muscle cell apoptotic process; and positive regulation of cellular component organization. Located in synaptic vesicle. Colocalizes with mitochondrial membrane and synaptic vesicle membrane. Used to study transient cerebral ischemia. Orthologous to human MFF (mitochondrial fission factor). [provided by Alliance of Genome Resources, Apr 2022]