HZL-1 mRNA binding reverses argk-1-dependent modulation of TOR activity. Top left: Confocal micrograph images of daf-2; aak(0) animals with DAF-15::mNG::AID, i.e., the DAF-15 degron. Animals grown on control plates (without auxin) (Top) express mNG in the germ line (within the white lines). DAF-15 localizes to discrete puncta, presumably lysosomes, as has been previously shown (white arrows). mNG signal is absent in animals exposed to 100 µm IAA (Bottom). White asterisks denote non-specific signal from autofluorescence. Scale bar = 10 µm. Top right: Confocal images showing representative germ lines of dauer daf-2 and daf-2, aak(0) DAF-15 degron animals with and without auxin, following DAPI staining. Bottom: Model of AMPK-mediated regulation of HZL-1 and TOR. In the wild type, AMPK inhibits HZL-1, allowing for HZL-1-target mRNAs, such as argk-1, to promote germ cell quiescence. argk-1 negatively regulates TOR, and when argk-1 is bound by HZL-1, TOR activity is elevated. This drives the unscheduled germ cell divisions and subsequent hyperplasia observed in AMPK mutants during periods of energy challenge, resulting in post-dauer sterility.
#Celegans adapts to starvation & other stressors by transiting through the quiescent #dauer stage, but how? This study shows that TOR activity is inhibited by AMPK & a novel RNA-binding helicase in the #GermLine during dauer, preserving developmental quiescence @plosbiology.org 🧪 plos.io/48NEHvc