BTB/POZ domain-containing protein KCTD11, is a 232 amino acid regulator of neuronal differentiation that induces growth arrest, apoptosis and the expression of p27, a cyclin-dependent kinase inhibitor. Expressed at highest levels in cerebellum, KCTD11 functions as an antagonist of the Hedgehog pathway and activator of the caspase cascade. Recombinant human KCTD11 protein, fused to His-tag at N-terminus, was expressed in E.coli.