CRBN (UniProt/Swiss-Prot entry Q96SW2) is a cytoplasmic protease that is related to the Lon protease protein family. It mediates the ubiquitination and subsequent proteasomal degradation of target proteins, such as MEIS2. CRBN is associated with a calcium channel membrane protein and is thought to play a role in brain development and in memory and learning by regulating the assembly and neuronal surface expression of largeconductance calcium-activated potassium channels brain through its interaction with KCNT1. Mutations in the CRBN gene are associated with autosomal recessive nonsyndromic cognitive disability.