The UBE3A gene provides instructions for making a protein called ubiquitin protein ligase E3A. Ubiquitin protein ligases are enzymes that target other proteins to be broken down (degraded) within cells. These enzymes attach a small molecule called ubiquitin to proteins that should be degraded. Cellular structures called proteasomes recognize and digest these ubiquitin-tagged proteins. Protein degradation is a normal process that removes damaged or unnecessary proteins and helps maintain the normal functions of cells.~Studies suggest that ubiquitin protein ligase E3A plays a critical role in the normal development and function of the nervous system. Studies suggest that it helps control (regulate) the balance of protein synthesis and degradation (proteostasis) at the junctions between nerve cells (synapses) where cell-to-cell communication takes place. Regulation of proteostasis is important for the synapses to change and adapt over time in response to experience, a characteristic called synaptic plasticity. Synaptic plasticity is critical for learning and memory.~People normally inherit two copies of the UBE3A gene, one from each parent. Both copies of the gene are turned on (active) in most of the body's tissues. However, in nerve cells (neurons) in the brain and spinal cord (the central nervous system), only the copy inherited from a person's mother (the maternal copy) is active. This parent-specific gene activation results from a phenomenon known as genomic imprinting.