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Figure 4 | BMC Immunology

Figure 4

From: Nitric oxide/cGMP pathway signaling actively down-regulates α4β1-integrin affinity: an unexpected mechanism for inducing cell de-adhesion

Figure 4

Effect of the cell permeable analog of cGMP on binding and dissociation of the LDV-FITC probe on U937 cells stably transfected with the non-desensitizing mutant of FPR. LDV-FITC probe binding and dissociation on U937 cells stably transfected with the non-desensitizing mutant of FPR plotted as mean channel fluorescence (MCF) versus time. The experiment involved sequential addition of the fluorescent LDV-FITC probe (4 nM, below saturation, added 2 min prior to addition of the Gαi-coupled receptor ligand, fMLFF, 100 nM), and different concentrations of dibutyrylguanosine 3',5'-cyclic monophosphate (cell permeable cGMP analog) (arrows). Control cells were treated with vehicle. The MCF value corresponding to cell autofluorescence is indicated by the horizontal arrow. Dashed line indicates the non-specific binding of the LDV-FITC probe determined using excess unlabelled LDV competitor (as shown on Figure 3B). Rapid and reversible binding of the probe reflects the VLA-4 affinity change [14]. Curves are means out of two independent determinations calculated on a point-by-point basis (n = 2).

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