Neuronatin is a protein that in humans is encoded by the NNAT gene involved in mammalian brain development. It is located on Chromosome 20 in humans and is only expressed from the paternal allele in normal adults. The protein neuronatin, a proteolipid, that functions in the control of ion channels during brain development. Neuronatin begins the differentiation of pluripotent stem cells into cells with a neural fate by increasing their calcium levels. Neuronatin expression in neural tissues throughout the brain contributes to development of the nervous system. It is also expressed in several tissues outside of the brain. For example, expression in skin cells controls the differentiation of keratinocytes. Neuronatin expression functions not only in development, but other processes throughout the body.