Fig. 6.

Validation of NAADP-inhibitors in mammalian cells. A, Ca²⁺ traces resolved by fluo-4 fluorescence in response to NAADP microinjection (100 nM pipette concentration) in U2OS cells treated with indicated drugs (10μM, 10 min pretreatment). Individual traces shown in red, averaged response shown in black. B, Quantification of peak amplitude of NAADP-evoked Ca²⁺ transients in microinjected U2OS cells relative to control (blue bars) following preincubation with indicated drugs as shown in (A). Red bars report luciferase levels in a MERS-pseudovirus cell translocation assay in Huh7 cells relative to controls (H₂O, DMSO) following treatment with the same panel of drugs (10μM for 1 h prior to exposure to MERS-pseudovirus for a 5 h period). MERS-pseudovirus cell entry was detected 3 days post infection by measuring luciferase activity as described fully in the companion paper [25]. p-values: * p < 0.05, ** p < 0.01 relative to DMSO controls.