- The insulin receptor (INSR) binds insulin to promote body growth and maintain normal blood glucose levels. While it is known that steroid hormones such as estrogen and 20-hydroxyecdysone counteract insulin function, the molecular mechanisms responsible for this attenuation remain unclear. In the present study, using the agricultural pest lepidopteran Helicoverpa armigera as a model, we proposed that the steroid hormone 20-hydroxyecdysone (20E) induces dephosphorylation of INSR to counteract insulin function.
- Oligomerization of stromal interacting molecule 1 (STIM1) promotes store-operated calcium entry (SOCE); however, the mechanism of STIM1 aggregation is unclear. Here, using the lepidopteran insect and agricultural pest cotton bollworm (Helicoverpa armigera) as a model and immunoblotting, RT-qPCR, RNA interference (RNAi), and ChIP assays, we found that the steroid hormone 20-hydroxyecdysone (20E) up-regulates STIM1 expression via G protein–coupled receptors (GPCRs) and the 20E nuclear receptor (EcRB1).
- Insulin promotes larval growth of insects by stimulating the synthesis of the steroid hormone 20-hydroxyecdysone (20E), which induces pupation and apoptosis. However, the mechanism underlying the coordinate regulation of insect pupation and apoptosis by these two functionally opposing hormones is still unclear. Here, using the lepidopteran insect and serious agricultural pest Helicoverpa armigera (cotton bollworm) as a model, we report that phosphoinositide-dependent kinase-1 (PDK1) and forkhead box O (FoxO) play key roles in these processes.