The BTB (for BR-C, ttk and bab)  or POZ (for Pox virus and Zinc finger) [7958847, 17384421] domain is a versatile protein-protein interaction motif involved in many cellular functions, including transcriptional regulation, cytoskeleton dynamics, ion channel assembly and gating, and targeting proteins for ubiquitination . The BTB domain can occur alongside other domains: BTB-zinc finger (BTB-ZF), BTB-BACK-Kelch (BBK), voltage-gated potassium channel T1 (T1-Kv) , MATH-BTB, BTB-NPH3 and BTB-BACK-PHR (BBP). Other proteins, such as Skp1 and ElonginC, consist almost exclusively of the core BTB fold. In all of these protein families, the BTB core fold is structurally conserved, consisting of a 2-layer alpha/beta topology where a cluster of alpha helices is flanked by short beta-sheets . POZ domains from several zinc finger proteins have been shown to mediate transcriptional repression and to interact with components of histone deacetylase co-repressor complexes including N-CoR and SMRT [9019154, 9824158, 9765306]. The POZ or BTB domain is also known as BR-C/Ttk or ZiN.
This entry differs from IPR000210 in including POZ-containing Skp1 proteins.