Enables JUN kinase binding activity. Involved in regulation of neuron differentiation. Located in cell leading edge; nucleus; and perinuclear region of cytoplasm. Human ortholog(s) of this gene implicated in dentatorubral-pallidoluysian atrophy and schizophrenia. Orthologous to human ATN1 (atrophin 1). [provided by Alliance of Genome Resources, Apr 2022]