Characterization of SnxA probes. (A) Confocal images of HEK293 cells transfected with either full-length or 2xPX-GFP fusions ± apilimod after fixation with paraformaldehyde. (B) Phagosomal proteolysis of both Ax2 (WT) and ΔPIKfyve Dictyostelium cells expressing different SnxA-derived probes, measured by digestion of bead-conjugated DQ-BSA. Data show mean ± SD of three independent experiments. (C) Images of macropinosomes in Ax2 cells expressing each probe or ΔPIKfyve cells after overnight incubation in Texas-Red dextran. The bright vesicles indicate concentration of macropinosomes contents. All scale bars represent 2 μm.