The CD36 scavenger receptor Bez regulates lipid redistribution from fat body to oocytes in Drosophila

Class B scavenger receptors of the CD36 family are important for lipid mobilization from mammalian adipose tissue. This protein family has 3 members in mammals, but 14 in Drosophila melanogaster. Lipid distribution in Drosophila is mediated by homologs of the LDL receptors, while little is known about the function of scavenger receptors for this process in invertebrates. Here we unravel a role for the so far uncharacterized scavenger receptor Bez in lipid export from Drosophila adipocytes. Bez shares the lipid binding residue with CD36 and is expressed at the plasma membrane of the embryonic, larval and adult fat body. Bez loss-of-function lowers the organismal content of storage lipids while they accumulate in the fat body, concomitant with female sterility and degeneration of ovaries. Using an alkyne-labeled fatty acid tracer, we demonstrate that Bez interacts with the apoB homolog Lipophorin at the plasma membrane of adipocytes, thereby enabling lipid transfer. Our study shows how a scavenger receptor interacts with lipoproteins to distribute storage lipids from the fat body to the ovaries and thereby contributes to the metabolic control of development.