Undead cells up-regulate cytosolic Ca2+ signaling and produce Ca2+ flashes in a Dronc-dependent manner. Top: The disc outline is marked by yellow dashed lines. The white dotted lines highlight the ey-Gal4-expressing area of the eye discs. For all panels, scale bars are 50 μm. Confocal images of third instar larval eye imaginal disc expressing the Ca2+ reporter GCaMP6s in control (ey-Gal4, left, and ey>p35, middle) and in overgrown, undead (ey>hid,p35, right) discs. The GCaMP6s fluorescence directly represents the cytosolic Ca2+ level. The cytosolic Ca2+ level is significantly upregulated in undead (ey>hid,p35) discs compared to control discs (see white arrows in righthand panel). Bottom: Representative Ca2+ traces of eye imaginal discs expressing GCaMP6s obtained by time-lapse confocal imaging (600 frames, 1-second intervals). Ca²⁺ flashes refer to transient, localized increases in intracellular calcium levels, detected as brief bursts of elevated GCaMP6s fluorescence. These flashes are characterized by a rapid onset, short duration, and return to baseline, indicating discrete calcium signaling events within imaginal disc cells. Each line represents an independent disc (numbered). Undead discs display a strong increase in the number of Ca2+ flashes. Genotypes as for top row.
The initiator #caspase Dronc can trigger compensatory #apoptosis -induced proliferation (AiP). This study shows that Dronc-dependent Ca2+ influx into the cytosol is an important contributor to AiP & DUOX activation in #Drosophila (& likely in vertebrates) @plosbiology.org 🧪 plos.io/4pNG4PK
