Butyrophilin, subfamily 3, member A1

Butyrophilin subfamily 3 member A1 is a protein that in humans is encoded by the BTN3A1 gene. BTN3A1 protein is involved in innate immunity in primates and other mammals to protect them against pathogens and cancer.

Function

The intracellular domain of BTN3A1 protein binds intracellular phosphoantigens. Accumulation of phosphoantigens such as isopentenyl Pyrophosphate is a universal sign of cellular stress or infection by an intracellular bacterium. The binding of phosphoantigens to BTN3A1 leads to an allosterically mediated change in conformation of BTN3A1's extracellular domain. This changed conformation is detected by the T cell receptor on cytotoxic gamma delta T cells, which can then kill the stressed or infected cell.