Anti-speckle-type BTB/POZ protein antibodies are protein reagents that detect specific antigens. The speckle-type BTB/POZ protein antigen is another term for the human protein speckle type BTB/POZ protein, encoded by the SPOP gene. The protein is a known component of the cullin-RING-based BCR (BTB-CUL3-RBX1) E3 ubiquitin-protein ligase complex that mediates the ubiquitination of target proteins, leading most often to their proteasomal degradation. Canonically, it has an amino acid length of 374 residues and a mass of 42.1 kilodaltons. Its subcellular localization is in the nucleus and it is widely expressed across many tissue types. The speckle-type BTB/POZ protein protein is a member of the Tdpoz protein family.