High affinity interaction between histidine-rich glycoprotein and the cell surface type ATP synthase on T-cells.
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Ohta T, Ikemoto Y, Usami A, Koide T, Wakabayashi S
High affinity interaction between histidine-rich glycoprotein and the cell surface type ATP synthase on T-cells.
Biochim Biophys Acta. 2009 May;1788(5):1099-107. doi: 10.1016/j.bbamem.2009.03.005. Epub 2009 Mar 12.
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- 19285951 [ View in PubMed]
- Abstract
Histidine-rich glycoprotein (HRG) is a plasma protein implicated in the innate immune system. In recent studies, we showed that either HRG, or the Arg23-Lys66 glycopeptide derived from HRG, in concert with concanavalin A (Con A), promotes a morphological change and adhesion of the human leukemic T-cell line MOLT-4 to culture dishes, and that cell surface glycosaminoglycan or Fcgamma receptors do not participate in this cellular event. In the present study, we identified the alpha-subunit of ATP synthase as one of the HRG-binding proteins on the surface of T-cells by HRG-derived glycopeptide affinity chromatography and by a peptide mass finger printing method. HRG specifically interacted with mitochondrial ATP synthase with a dissociation constant of 66 nM. The presence of alpha- and beta-subunits of ATP synthase on the plasma membrane of MOLT-4 cell was demonstrated by immunofluorescent staining and FACS analysis. The HRG/Con A-induced morphological changes of MOLT-4 cells were specifically inhibited by a monoclonal antibody against the beta-subunit of ATP synthase. These results strongly suggest that the cell surface ATP synthase functions as a binding protein for HRG on MOLT-4 cells, which is required for the morphological changes observed in MOLT-4 cells following treatment with HRG/Con A.