10 Oral - Plenary Session I
Thursday April 07, 9:05 AM - 9:35 AM

Author:
Michelle Bland

Affiliation: University of Virginia

Keywords:
b. metabolism; j. fat body

Infection and subsequent immune signaling drive synthesis and secretion of immune effectors and mobilization of immune cells, processes that are supported and directed by host metabolism. In the Drosophila larval fat body, the metabolic challenge of fighting infection must be balanced with the energetically-demanding processes of growth and nutrient storage that this organ coordinates. We find that Toll signaling in larval fat body disrupts whole-animal growth and directs a lipid metabolic switch from fat storage to phospholipid synthesis. Although reduced triglyceride storage in larvae with active Toll signaling impairs the response to stress later in life, elevated phospholipid synthesis in fat body supports humoral immune function. Toll signaling in larval fat body directs increased production of membrane phospholipids that coincides with expansion of the endoplasmic reticulum. Phospholipid synthesis in larval fat body supports antimicrobial peptide secretion and promotes bacterial clearance. Our results define a metabolic role for the pleiotropic Toll signaling pathway, and they demonstrate that the demands of fighting infection are met with trade-offs in growth and energy storage to sustain immune function.