Lipid Droplet Protein Binding in Response to Altered Phospholipid Composition

Abstract

Alcoholic Fatty Liver Disease (AFLD) is the alcohol‐induced accumulation of excess lipids in hepatocyte lipid droplets. Lipid droplet surfaces are phospholipid monolayers predominantly composed of phosphatidylcholine (PC) and phosphatidylethanolamine (PE). Protein binding to lipid droplets affects droplet size and activity. Previous experiments with a rat model of AFLD show lipid droplet surfaces have a decreased ratio of PC:PE. We aimed to determine if the altered phospholipid composition of AFLD lipid droplets leads to differential binding of several proteins of interest, selected for their membrane binding motifs and roles in lipid droplet homeostasis. By culturing AML12 cells in choline‐deficient media with oleate, an unsaturated fatty acid, we simulated the altered phospholipid composition of AFLD lipid droplets. Next, we isolated lipid droplet fractions and examined proteins of interest by SDS‐PAGE and western blotting. We found equivalent levels of rab18 and lanosterol synthase associating with lipid droplet fractions from cells grown with and without choline. Alternatively, there was an increase in the level of αCCT1 and perilipin 2 in lipid droplet fractions from cells grown without choline. By evaluating how altered phospholipid monolayer composition affects the binding of lipid droplet proteins, we seek to further elucidate the biochemical pathways that contribute to AFLD.Support or Funding InformationThis work was supported by St. Olaf College Collaborative Undergraduate Research and Inquiry, Howard Hughes Medical Institute, the St. Olaf TRIO McNair Scholars Program, and LSAMP Alliance.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.