Fig. 5: MS4A1 is a chemoreceptor that detects nitrogenous heterocyclic compounds.
A GCaMP6s fluorescence in response to the indicated chemicals in HEK293 cells expressing MS4A1 protein (odor delivery indicated by red bars). B Quantification of responses of cells expressing MS4A1 protein to the indicated chemicals as in (A). The data are presented as mean ± SEM. n = 8 wells of cells over three independent experiments (RS), n = 17 wells of cells over nine independent experiments (2,3-DMP), n = 12 wells of cells over 11 independent experiments (2,5-DMP), n = 20 wells of cells over ten independent experiments (2,6-DMP), n = 12 wells of cells over six independent experiments (quinoline), n = 5 wells of cells over four independent experiments (indole), n = 3 wells of cells over two independent experiments (pyridine), n = 4 wells of cells over three independent experiments (pyrrolidine), n = 6 wells of cells over three independent experiments (vanillin), n = 5 wells of cells over three independent experiments (IAA). Dashed red line indicates the mean plus one standard deviation of responses of MS4A1-expessing HEK293 in response to RS. *p < 0.05, **p < 0.01, Dunnett’s test following Brown-Forsythe and Welch ANOVA tests compared to control stimulation with Ringer’s solution (RS) alone. C Dose–response curves reveal low micromolar/high nanomolar EC50s for MS4A1/2,3-DMP (top panel) and MS4A1/2,5-DMP (bottom panel). For 2,3-DMP (top panel), each data point represents the mean ± SEM from n = 8 wells of cells over five independent experiments (10−8 M), n = 10 wells of cells over six independent experiments (10−7 M), n = 9 wells of cells over six independent experiments (10−6 M), n = 12 wells of cells over six independent experiments (10−5 M), n = 6 wells of cells over six independent experiments (10−4, 10−3 M); For 2,5-DMP, each data point represents the mean ± SEM from n = 4 wells of cells over four independent experiments (10−8 M), n = 3 wells of cells over three independent experiments (10−7 M), n = 4 wells of cells from four independent experiments (10−6, 10−5, 10−4, 10−3 M). D The requirement of extracellular calcium for MS4A1 ligand responses was assessed by stimulating HEK293 cells co-expressing GCaMP6s and either MS4A1 or mCherry or GCaMP6s alone with 2,5-DMP in the presence or absence of extracellular calcium. Data are presented as mean ± SEM from n = 6 wells of cells over three independent experiments (for each indicated condition). ****p < 0.0001, Tuckey’s test following one-way ANOVA compared to no extracellular calcium. Source data are provided as a Source Data file.
