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bioRxiv · 10.1101/2021.07.05.451134

A local insulin reservoir ensures developmental progression in condition of nutrient shortage in Drosophila

Ghosh, S.·Leng, W.·Wilsch-Brauninger, M.·Leopold, P.·Eaton, S.
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Abstract

Insulin/IGF signalling (IIS) controls many aspects of development and physiology. In Drosophila, a conserved family of insulin-like peptides (Ilp) is produced by brain neurosecretory cells and exerts systemic functions. Here, we describe the local uptake and storage of Ilps in the Corpora Cardiaca (CC), a group of alpha cell homolog that produces the glucagon-like hormone AKH. Dilp uptake relies on the expression of Impl2, an IGF-BP that accumulates in the CCs. During nutrient shortage, this specific reserve of Ilps is released and activates IIS in a paracrine manner in the prothoracic gland, securing accelerated entry into pupal development through the production of the steroid hormone ecdysone. We therefore uncover a sparing mechanism whereby local Ilp storage and release activates the production of steroids and ensures early developmental progression in adverse food conditions. Highlights- Dilps are uptaken by CC cells through the IGF-BP Imp-L2 - the CC-Dilp store is released upon nutrient shortage and activates IIS through CC projections on the PG - upon nutrient shortage, IIS activation in the PG ensures an accelerated transition from larval feeding stage to metamorphosis.

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Ghosh, S., Leng, W., Wilsch-Brauninger, M., Leopold, P., Eaton, S.. 2021-07-06. A local insulin reservoir ensures developmental progression in condition of nutrient shortage in Drosophila. https://doi.org/10.1101/2021.07.05.451134

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