Substrate recognition component of a DCX (DDB1-CUL4-X-box) E3 protein ligase complex that mediates the ubiquitination and subsequent proteasomal degradation of target proteins, such as MEIS2 or ILF2 (PubMed:33009960). Normal degradation of key regulatory proteins is required for normal limb outgrowth and expression of the fibroblast growth factor FGF8 (PubMed:20223979, PubMed:24328678, PubMed:25043012, PubMed:25108355). Maintains presynaptic glutamate release and consequently cognitive functions, such as memory and learning, by negatively regulating large-conductance calcium-activated potassium (BK) channels in excitatory neurons (PubMed:18414909, PubMed:29530986). Likely to function by regulating the assembly and neuronal surface expression of BK channels via its interaction with KCNT1 (PubMed:18414909). May also be involved in regulating anxiety-like behaviors via a BK channel-independent mechanism (By similarity). Protein modification; protein ubiquitination. Interacts with KCNT1 (By similarity). Component of a DCX (DDB1-CUL4-X-box) protein ligase complex, at least composed of CRBN, CUL4A, DDB1 and RBX1. Interacts directly with DDB1 (PubMed:25043012, PubMed:25108355). Interacts (in pomalidomide-bound form) with IKZF1 and IKZF3 (PubMed:24328678). Interacts with ILF2 (PubMed:33009960). Widely expressed. Highly expressed in brain. The CULT domain binds thalidomide and related drugs, such as pomalidomide and lenalidomide. Drug binding leads to a change in substrate specificity of the human DCX (DDB1-CUL4-X-box) E3 protein ligase complex, while no such change is observed in rodents. Ubiquitinated, ubiquitination is mediated by its own DCX protein ligase complex. The disease is caused by variants affecting the gene represented in this entry. Thalidomide was widely prescribed to pregnant women in the late 1950s as a sedative and as treatment against morning sickness. Thalidomide was found to be teratogenic, causing multiple birth defects. Recently, thalidomide use has increased for the treatment of multiple myeloma and erythema nodosum leprosum, a painful complication of leprosy. Binding of pomalidomide and other thalidomide-related drugs leads to a change in substrate specificity of the human DCX (DDB1-CUL4-X-box) E3 protein ligase complex, and this is probably the underlying cause of the teratogenic activity of thalidomide, possibly due to abnormal regulation of the BMP and FGF8 signaling pathways (PubMed:20223979). The thalidomide-induced change in substrate specificity leads to decreased degradation of MEIS2 and other target proteins and increased degradation of MYC, IRF4, IKZF1 and IKZF3, and this is probably the reason for the anti-proliferative and immunomodulatory effects of thalidomide and related drugs (PubMed:25108355). Thalidomide is also teratogenic in chicken and zebrafish, but not in mice. Belongs to the CRBN family. Although it contains a Lon N-terminal domain also found in proteases of the peptidase S16 family, it does not contain the ATP-binding and catalytic domains, suggesting that it has no protease activity. Truncated N-terminus. A short story - Issue 117 of May 2010