This gene encodes a preproprotein that is proteolytically cleaved to yield a number of active opium-like peptides. These peptides are the endogenous ligands for the Kappa-opioid receptor and similar G-protein-coupled receptors and are thought to function as the body's natural way to control addiction. These peptides have been associated with depression, stress, anxiety, response to pain, and maintenance of homeostasis via circadian rhythms and control of appetite. Mutations in the related human gene have been linked to the neurodegenerative disease spinocerebellar ataxia. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Nov 2013]