Fig. 5: Disulfiram (DSF) binds FROUNT and inhibits its interaction with chemokine receptors.

a DSF targets the interaction of CRBD (the chemokine receptor-binding domain) of FOUNT with CCR2 and CCR5 via a conserved binding region (shown in red). b, c HTRF interaction with DSF and the p53-MDM2 inhibitor, Nutlin (b) and titration assay (c). d Surface plasmon resonance assessment for DSF-binding signals to FROUNT versus CCR2 (upper panel) and FROUNT-binding signals of DSF versus its first metabolite diethyldithiocarbamate (DDC) (lower panel). e NMR titration analyses of the binding of DSF and DDC to FROUNT. Representative NMR peaks derived from FROUNT or its mutant (C603S) in ¹H–¹⁵N HSQC spectra are shown. (Upper panel) The peaks before and after the 50 μM DSF titration to 50 μM FROUNT are shown in black and red, respectively. The largely perturbed M575 peaks (Δδ > 0.17 ppm) are connected by an orange dashed line. (Middle panel) The peaks before and after the 50 μM DDC titration to 50 μM FROUNT are shown in black and blue, respectively. (Lower panel) The peaks before and after the 50 μM DSF titration to 50 μM FROUNT mutant are shown in black and cyan, respectively. f Enlarged view of the putative DSF-binding site of FROUNT. Cartoon model of CRBD with a transparent surface and a map of the largely perturbed surface residues (Δδ > 0.17 ppm), labeled with their assignments and colored magenta. The other largely perturbed residues are buried inside the FROUNT structure. HTRF data in (b) and (c) show mean ± s.e.m.; duplicates from one of three independent experiments.