MHC Class I-Like MILL Molecules Are β2-Microglobulin-Associated, GPI-Anchored Glycoproteins That Do Not Require TAP for Cell Surface Expression
September 2006
in “
The Journal of Immunology
”
TLDR MILL molecules are unique immune proteins in mice that don't need TAP to appear on cell surfaces.
The study characterized mouse MILL molecules, revealing them as β2-microglobulin-associated, GPI-anchored glycoproteins that did not require TAP for cell surface expression, unlike classical MHC class I molecules. MILL1 and MILL2 were found to be GPI-anchored and associated with β2-microglobulin, suggesting non-peptide presentation functions. MILL1 was expressed in thymic medullary epithelial cells and hair follicles, indicating a potential immunological role, possibly related to immune privilege in hair follicles. The study concluded that MILL molecules are distinct from MICA/B, not stress-inducible, and may serve specialized immune functions in rodents. Further research was suggested to elucidate their biological function.