Disulfide bond-mediated dimerization of HLA-G on the cell surface.
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Boyson JE, Erskine R, Whitman MC, Chiu M, Lau JM, Koopman LA, Valter MM, Angelisova P, Horejsi V, Strominger JL
Disulfide bond-mediated dimerization of HLA-G on the cell surface.
Proc Natl Acad Sci U S A. 2002 Dec 10;99(25):16180-5. doi: 10.1073/pnas.212643199. Epub 2002 Nov 26.
- PubMed ID
- 12454284 [ View in PubMed]
- Abstract
HLA-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 transfectants using the anti-beta2-microglobulin mAb BBM.1 revealed the presence of an approximately equal 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-Greceptor interactions and for the search for specific receptors that bind HLA-G.