Endoplasmic reticulum and mitochondrial cross-talk during hibernation

Many insects undergo an adaptive mechanism, the hibernation diapause, in order to overcome the freezing temperatures and survive. Various studies focused on the genetical actors of hibernation. However, organelle dynamics in particular those beetween endoplasmic reticulum (ER) and mitochondria is essential for cellular homeostasis, and dysfunctioning of these organalles accompanied by decreased metabolic demands and stress might lead to failure in hibernation. Additionally, these organelles form physical interactions with each other at sites that are essential for calcium, lipid, and metabolite exchange, all crucial life events including hibernation. However, the underlying connections between ER and mitochondria communication in hibernation are not fully understood. In the current study, we investigated the structure and dynamics of ER and mitochondria using microscopic analysis and quantitative proteomics in the hibernating Colorado potato beetle (CPB), Leptinotarsa decemlineata, a destructive pest of Solanaceae plants worldwide. These investigations revealed differential levels and contact sites of ER and mitochondria in relation to different phases of hibernation, the pre-hibernation, hibernation and post-hibernation. Overall, organelle dynamics is likely to be an important factor of diapause in CPB; however, further studies would elucidate their exact role in diapause. Part of this research was supported by Tübitak (Grant no:118O976).