A brain circuit that synchronizes growth and maturation revealed through Dilp8 binding to Lgr3

Vallejo DM, Juarez-Carreño S, Bolivar J, Morante J, Dominguez M
Magazine Science
Year 2015
Vol: Pages(start-end) 350(6262):aac6767

Body size constancy and symmetry are signs of developmental stability. Yet, it is unclear exactly how developing animals buffer size variation. Drosophila insulin-like peptide Dilp8 is responsive to growth perturbations and controls homeostatic mechanisms that co-ordinately adjust growth and maturation to maintain size within the normal range. Here, we show that Lgr3 is a Dilp8 receptor. By functional and cAMP assays, we defined a pair of Lgr3 neurons mediating the homeostatic regulation. These neurons have extensive axonal arborizations, and genetic and GFP reconstitution across synaptic partners (GRASP) show these neurons connect with the insulin-producing cells and PTTH-producing neurons to attenuate growth and maturation. This previously unrecognized circuit suggests how growth and maturation rate are matched and co-regulated according to Dilp8 signals to stabilize organismal size.

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