Butyrophilin Like Protein 9 (BTNL9)

BTNL9 belongs to the immunoglobulin superfamily. BTN/MOG family. In the case of the cross-reactive pair of antigens BTN/MOG, BTN in the diet would normally induce oral tolerance to the cross-reactive epitope, but this may be broken either by early post-natal exposure to bovine milk products, gastro-intestinal infections or a combination of both.

Butyrophilin is synthesized as a peptide of 526 amino acids with an amino-terminal hydrophobic signal sequence of 26 amino acids, which is cleaved before secretion in association with the fat globule membrane. Hydropathy analysis and in vitro translation of butyrophilin mRNA indicate that the protein associates with membranes in a type I orientation via a single stretch of 27 hydrophobic amino acids in the approximate middle of the sequence.