XXXX lipophorin receptors mediate the uptake of neutral lipids in oocytes and imaginal disc cells by an endocytosis-independent mechanism.

@entity1 @entity72927 @entity72926 @entity412 @entity72928 @entity238
Lipids are constantly shuttled through the body to redistribute energy and metabolites between sites of absorption, storage, and catabolism in a complex homeostatic equilibrium. In @entity238 , lipids are transported through the hemolymph in the form of lipoprotein particles, known as lipophorins. The mechanisms by which cells interact with circulating lipophorins and acquire their lipidic cargo are poorly understood. We have found that @entity72926 ( @entity72927 and @entity72928 ), two partially redundant genes belonging to the @entity72928 ( @entity72928 ) family, are essential for the efficient uptake and accumulation of neutral lipids by oocytes and cells of the imaginal discs. Females lacking the @entity72928 gene lay eggs with low lipid content and have reduced fertility, revealing a central role for @entity72928 in mediating @entity238 vitellogenesis. @entity72927 and @entity72928 are transcribed into multiple isoforms. Interestingly, only a subset of these isoforms containing a particular @entity72928 type A module mediate neutral lipid uptake. Expression of these isoforms induces the extracellular stabilization of lipophorins. Furthermore, our data indicate that endocytosis of the lipophorin receptors is not required to mediate the uptake of neutral lipids. These findings suggest a model where lipophorin receptors promote the extracellular lipolysis of lipophorins. This model is reminiscent of the lipolytic processing of @entity412 -rich lipoproteins that occurs at the @entity1 capillary endothelium, suggesting an ancient role for @entity72928 -like proteins in this process.
