B. Reizis et al., MOLECULAR CHARACTERIZATION OF THE DIABETES-ASSOCIATED MOUSE MHC CLASS-II PROTEIN, I-A(G7), International immunology, 9(1), 1997, pp. 43-51
The MHC class II molecule of the non-obese diabetic (NOD) mice, I-A(g7
), is associated with susceptibility to autoimmune diabetes, To try to
understand the molecular basis of this association, we analyzed the p
eptide binding properties and intracellular behavior of I-A(g7) in com
parison with other I-A haplotypes, We found that I-A(g7) molecules man
ifested normal intracellular trafficking and lifespan, and a small but
clearly detectable fraction of I-A(g7) in the cells formed SDS-resist
ant compact dimers, The binding of an antigenic reference peptide to I
-A(g7) was stable and was accompanied by compact dimer formation, Our
analysis of the binding specificity of I-A(g7) revealed a peptide bind
ing motif of nine amino acids with a degenerate position at P1 and thr
ee conserved anchor positions: P4, P6 and P9, An allele-specific prefe
rence for negatively charged residues was found at P9, apparently due
to the presence of the rare Ser residue at position 57 of the I-A(g7)
beta chain, These findings could have implications for the mechanisms
of MHC-mediated susceptibility to autoimmune diabetes in the NOD mice.