Title : High affinity interaction between
histidine-rich glycoprotein and the cell surface type
ATP synthase on T-cells
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