Control of Metabolism and Growth Through Insulin-Like Peptides inDrosophila

Abstract

Insulin signaling is a conserved feature in all metazoans. It evolved with the appearance of multicellularity, allowing primordial metazoans to respond to a greater diversity of environmental signals. The insulin signaling pathway is highly conserved in insects and particularly in Drosophila, where it has been extensively studied in recent years and shown to control metabolism, growth, reproduction, and longevity. Because misregulation of the insulin/IGF pathway in humans plays a role in many medical disorders, such as diabetes and various types of cancer, unraveling the regulation of insulin/IGF signaling using the power of a genetically tractable organism like Drosophila may contribute to the amelioration of these major human pathologies. Diabetes 55 (Suppl. 2):S5-S8, 2006

Insulin-like peptides (AmILP1 and AmILP2) differentially affect female caste development in the honey bee (Apis mellifera)

“…And JH is synthesized in the closely associated CA of the insect retrocerebral complex (Goodman and Cusson, 2012), as also shown for honey bee larvae . In Drosophila, the small cluster of AmILPproducing neuroendocrine cells was shown to transmit ILPs to the JH-producing CA (Krieger et al, 2004) by axons directly projecting to the ring gland (Cao and Brown, 2001;Géminard et al, 2006). In line with these findings (Lane and Swales, 1978;Restifo et al, 1995), we hypothesize that a cluster of AmILP-producing cells in the brain of honey bee larvae may have been targeted by AmILP1 dsRNA, which consequently affected JH production in the CA.…”

Drosophila and the genetics of the internal milieu

“…For example, flies have a unique insulin receptor that mediates all functions that have so far been attributed to insulin-like peptides. Sugar levels are maintained by neurosecretory cells located in the brain and ring gland (together forming a bipartite 'Drosophila pancreas') that secrete insulin and adipokinetic hormone (AKH, the insect glucagon) into the open haemolymph (the 'Drosophila blood') [2][3][4][5] (reviewed in refs [6][7][8]. Excess sugar is stored in the form of glycogen that accumulates both in muscles and in the fat body (the 'Drosophila liver').…”

Hormonal and nutritional regulation of insect fat body development and function

“…This pathway includes insulin receptor InR, insulin receptor substrate Chico, PI3K catalytic subunit PI3K110, PI3K adaptor PI3K60, lipid phosphatase PTEN, PDK, and Akt/PKB. In this pathway, PI3K60 is a dominant negative form of PI3K and PTEN is a tumor suppressor, while all the others are oncogenes (Kozma and Thomas, 2002;Geminard et al, 2006). Akt is the key component in this pathway.…”