Proximity relationships between the type I receptor for Fc epsilon (Fc epsilon RI) and the mast cell function-associated antigen (MAFA) studied by donor photobleaching fluorescence resonance energy transfer microscopy

摘要: Clustering of the mast cell function-associated antigen (MAFA) on surface rat mucosal type cells line 2H3 (RBL-2H3) leads to suppression secretory response induced by I Fc epsilon receptor (Fc RI). In order establish a possible association between MAFA and RI we measured fluorescence resonance energy transfer (FRET) MAFA-specific monoclonal antibody (mAb) G63 RI-bound ligands as well themselves using donor photobleaching FRET (pbFRET) technique. Average efficiencies 6 9% were determined after low-temperature incubation with fluorescent dye conjugated mAb bound (donor) IgE (acceptor) RBL-2H3 cells. Subsequent cross-linking polyvalent caused no change in efficiencies. These results suggest that is located vicinity resting cells, clustering significant proximity two molecular species. view sequence motif identified cytosolic tail observed changes its phosphorylation upon stimulation (Guthmann et al., Proc. Natl. Acad. Sci. USA 1995, 92: 9397-9401), present study suggests inhibition interferes signal transduction cascade initiated via RI. An additional finding was showed clear increase efficiency molecules acceptor.