SUDD, or RIO kinase 3, is a human gene encoded by RIOK3. It may also be known as: Serine/threonine-protein kinase RIO3; sudD homolog; Serine/threonine-protein kinase RIO3 . The encoded protein is an enzyme with an amino acid length of 519 and a mass of 59.1 kDa. SUDD is a member of the Protein kinase superfamily, RIO-type Ser/Thr kinase family. Homologs of this gene exist in other organisms, including: Mouse, Frog.