Small Ubiquitin-Related Modifier 3 (SUMO3) is a member of the ubiquitin family. SUMO3 is a cytoplasmic protein and is expressed predominantly in the liver. It contains one ubiquitin-like domain. Unlike ubiquitin that targets proteins for degradation, SUMO3 participates in a number of cellular processes such as nuclear transport, DNA replication and repair, mitosis and signal transduction. In addition, SUMO3 regulates amyloid beta generation and is pivotal in the onset or progression of Alzheimer's disease.Alternative Names: Small Ubiquitin-Related Modifier 3, SUMO-3, SMT3 Homolog 1, SUMO-2, Ubiquitin-Like Protein SMT3B, Smt3B, SUMO3, SMT3B, SMT3H1