Download MendeleyStructural and biochemical analysis of highly similar HLA-B allotypes differentially associated with type 1 diabetes.
Sharma, R., Amdare, N.P., Ghosh, A., Schloss, J., Sidney, J., Garforth, S.J., Lopez, Y., Celikgil, A., Sette, A., Almo, S.C., DiLorenzo, T.P.(2024) J Biol Chem 300: 107702-107702
- PubMed: 39173948
- DOI: https://doi.org/10.1016/j.jbc.2024.107702
- Primary Citation of Related Structures:
9C6V, 9C6W, 9C6X - PubMed Abstract:
Type 1 diabetes (T1D) is an autoimmune disease involving T cell-mediated destruction of the insulin-producing beta cells in the pancreatic islets of Langerhans. CD8 + T cells, responding to beta cell peptides presented by class I major histocompatibility complex (MHC) molecules, are important effectors leading to beta cell elimination. Human leukocyte antigen (HLA) B*39:06, B*39:01, and B*38:01 are closely related class I MHC allotypes that nonetheless show differential association with T1D. HLA-B*39:06 is the most predisposing of all HLA class I molecules and is associated with early age at disease onset. B*39:01 is also associated with susceptibility to T1D, but to a lesser extent, though differing from B*39:06 by only two amino acids. HLA-B*38:01, in contrast, is associated with protection from the disease. Upon identifying a peptide that binds to both HLA-B*39:06 and B*39:01, we determined the respective X-ray structures of the two allotypes presenting this peptide to 1.7 Å resolution. The peptide residues available for T cell receptor contact and those serving as anchors were identified. Analysis of the F pocket of HLA-B*39:06 and B*39:01 provided an explanation for the distinct peptide C-terminus preferences of the two allotypes. Structure-based modeling of the protective HLA-B*38:01 suggested a potential reason for its peptide preferences and its reduced propensity to present 8-mer peptides compared to B*39:06. Notably, the three allotypes showed differential binding to peptides derived from beta cell autoantigens. Taken together, our findings should facilitate identification of disease-relevant candidate T cell epitopes and structure-guided therapeutics to interfere with peptide binding.
Organizational Affiliation:
Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY.
