Fig. 5. TRPM7 regulates phagosome proteolysis in macrophages.

a Schematic of phagosomal proteolysis assay. Fluorescent beads were conjugated to DQ green-BSA and then offered to BMDMs as cargo for phagocytosis. In bead-containing macrophages, lysosomal proteolytic activity was measured, as reflected by increased DQ-Green BSA fluorescence due to proteolytic unquenching of the fluorophore. b Flow cytometry-based measurement of proteolytic activity during phagocytosis of latex beads. DQ-green BSA-labelled fluorescent beads (4 μm) were incubated with WT and KO BMDMs for indicated time points. Left: Representative histograms of Bead+ BMDMs. Right: Measurement of DQ-green MFI in Bead+ BMDMs. Data representative of two independent experiments. c Quantification of bead uptake by Trpm7^+/+ and Trpm7^−/− BMDMs. Left: Percentage of Bead+ BMDMs over time. Right: Quantification of gross bead uptake measured by Bead MFI of Bead+ BMDMs. Data points are mean of n = 3 independent samples. Error bars = SEM. d Quantification of the phagosomal proteolysis as shown in panel c. DQ-green BSA MFI is shown as change from Bafilomycin A1 pretreated BMDMs (negative control) and gated on Bead+ BMDMs. Individual sample data points are plotted. Error bars = SEM. Source data are provided as a Source Data file, and statistical testing is described in “Statistics and Reproducibility”.