The DNA-associated protein encoded by this gene is a member of the paired family of homeobox proteins localized to the nucleus. The protein functions as a transcription factor involved in the development of several major noradrenergic neuron populations and the determination of neurotransmitter phenotype.

The gen product is linked to enhancement of second messenger-mediated activation of the dopamine beta-hydrolase, c-fos promoters and several enhancers, including cyclic amp-response element and serum-response element.