Anti-contactin associated protein family member 4 antibodies are used for the immunodetection of the protein encoded by the CNTNAP4 gene. In humans, the canonical protein has a reported length of 1308 amino acid residues and a mass of 145.3 kDa. Its subcellular localization is in the cell membrane. Alternative splicing is reported to yield 2 different isoforms for this protein. A member of the Neurexin protein family, it is known to be a presynaptic protein involved in both dopaminergic synaptic transmission and GABAergic system, thereby participating in the structural maturation of inhibitory interneuron synapses. Post-translational modifications have been described, including glycosylation. Other names for this target antigen include cell recognition molecule Caspr4, contactin associated protein like 4, and contactin-associated protein-like 4. Gene orthologs have been identified in the mouse, rat, bovine, frog, chimpanzee and chicken species.