Anti-ATD4 antibodies are used in antigen-specific immunodetection in biological samples. The target ATD4 is a known alias name of the protein tetratricopeptide repeat domain 21B, encoded by the TTC21B gene in humans. This 1316-amino acid residue protein is a known component of the IFT complex A (IFT-A), a complex required for retrograde ciliary transport and entry into cilia of G protein-coupled receptors (GPCRs). It is localized to the cytoplasm of the cell. It is reported to be widely expressed in many tissue types.