Enables ErbB-2 class receptor binding activity and chemorepellent activity. Involved in several processes, including positive regulation of cardiac muscle cell differentiation; postsynapse to nucleus signaling pathway; and synapse assembly. Acts upstream of or within several processes, including neurogenesis; positive regulation of intracellular signal transduction; and positive regulation of macromolecule metabolic process. Located in several cellular components, including axolemma; external side of plasma membrane; and neuromuscular junction. Is integral component of plasma membrane. Is active in GABA-ergic synapse and glutamatergic synapse. Is expressed in several structures, including alimentary system; central nervous system; genitourinary system; heart; and sensory organ. Used to study schizophrenia. Human ortholog(s) of this gene implicated in several diseases, including bipolar disorder; cerebral malaria; dementia; middle cerebral artery infarction; and psychotic disorder (multiple). Orthologous to human NRG1 (neuregulin 1). [provided by Alliance of Genome Resources, Apr 2022]