Boyson, J. E.Erskine, R.Whitman, MaryChiu, MichaelLau, J. M.Koopman, L. A.Valter, M. M.Angelisova, P.Horejsi, V.Strominger, Jack2018-06-252002Boyson, J. E., R. Erskine, M. C. Whitman, M. Chiu, J. M. Lau, L. A. Koopman, M. M. Valter, P. Angelisova, V. Horejsi, and J. L. Strominger. 2002. “Disulfide Bond-Mediated Dimerization of HLA-G on the Cell Surface.” Proceedings of the National Academy of Sciences 99 (25) (November 26): 16180–16185. doi:10.1073/pnas.212643199.0027-8424http://nrs.harvard.edu/urn-3:HUL.InstRepos:37155982HLA-G is a nonclassical class I MHC molecule with an unknown function and with unusual characteristics that distinguish it from other class I MHC molecules. Here, we demonstrate that HLA-G forms disulfide-linked dimers that are present on the cell surface. Immunoprecipitation of HLA-G from surface biotinylated transfec- tants using the anti-[]2-microglobulin mAb BBM.1 revealed the presence of an []78-kDa form of HLA-G heavy chain that was reduced by using DTT to a 39-kDa form. Mutation of Cys-42 to a serine completely abrogated dimerization of HLA-G, suggesting that the disulfide linkage formed exclusively through this residue. A possible interaction between the HLA-G monomer or dimer and the KIR2DL4 receptor was also investigated, but no interaction between these molecules could be detected through several approaches. The cell-surface expression of dimerized HLA-G molecules may have implications for HLA-G[]receptor interactions and for the search for specific receptors that bind HLA-G.en-USJournal Article2018-06-2320022018-06-2510.1073/pnas.212643199