[5] While primarily a protein-protein interaction domain,[5] some BTB domains have additional functionality in transcriptional regulation,[6] cytoskeletal mobility,[7] protein ubiquitination and degradation,[8][9][10] and ion channel formation and operation.

[11] BTB domains have traditionally been classified by the other structural features present in the protein.

Researchers at UCLA found a conserved 115 amino acid motif in nine Drosophila proteins, including Broad complex, tramtrack, and bric-a-brac, and labelled the conserved region the BTB domain.

[2] At the same time, a group at Imperial Cancer Research Fund Laboratories in London discovered the same 120 amino acid motif in a set of otherwise unrelated zinc finger proteins and a set of pox-virus proteins, and thus named the region the POZ domain.

In zinc-finger proteins, it commonly forms homodimers with other BTB domains, mediates heteromeric dimerization, and recruits transcriptional corepressors.