Lipogenic Enzymes Complexes and Cytoplasmic Lipid Droplet Formation During Adipogenesis.

Abstract

Lipid droplets are dynamic organelles that store triglycerides and participate in their mobilization in adipose cells. These organelles require the reorganization of some structural components, the cytoskeleton, and the activation of lipogenic enzymes. Using confocal microscopy, we analyzed the participation of cytoskeletal components and two lipogenic enzymes, fatty acid synthase and glycerophosphate dehydrogenase, during lipid droplet biogenesis in differentiating 3T3-F442A cells into adipocytes. We show that subcortical actin microfilaments are extended at the basal side of the cells in parallel arrangement to the culture dish substrate, and that the microtubule network traverses the cytoplasm as a scaffold that supports the round shape of the mature adipocyte. By immunoprecipitation, we show that vimentin and perilipin1a associate during the early stages of the differentiation process for lipid droplet formation. We also report that the antibody against perilipin1 detected a band that might correspond to a modified form of the molecule. Finally, the cytosolic distribution and punctate organization of lipogenic enzymes and their co-localization in the proximity of lipid droplets suggest the existence of dynamic protein complexes involved in synthesis and storage of triglycerides. J. Cell. Biochem. 117: 2315-2326, 2016. © 2016 Wiley Periodicals, Inc.