The GTPase ARFRP1 affects lipid droplet protein composition and triglyceride release from intracellular storage of intestinal Caco-2 cells

Highlights: • trans-Golgi GTPase ARFRP1 influences protein targeting to lipid droplets. • TERA/VCP is a new identified lipid droplet associated protein in Caco2-cells. • Abundance of TERA/VCP, FAF2 and Plin2 at lipid droplets increase in the absence of Arfrp1. • ARFRP1 function is required for correct lipid release from Caco2-cells. • Inhibition of lipolysis impairs lipid release in Caco2-cells. Intestinal release of dietary triglycerides via chylomicrons is the major contributor to elevated postprandial triglyceride levels. Dietary lipids can be transiently stored in cytosolic lipid droplets (LDs) located in intestinal enterocytes for later release. ADP ribosylation factor-related protein 1 (ARFRP1) participates in processes of LD growth in adipocytes and in lipidation of lipoproteins in liver and intestine. This study aims to explore the impact of ARFRP1 on LD organization and its interplay with chylomicron-mediated triglyceride release in intestinal-like Caco-2 cells. Suppression of Arfrp1 reduced release of intracellularly derived triglycerides (0.69-fold) and increased the abundance of transitional endoplasmic reticulum ATPase TERA/VCP, fatty acid synthase-associated factor 2 (FAF2) and perilipin 2 (Plin2) at the LD surface. Furthermore, TERA/VCP and FAF2 co-occurred more frequently with ATGL at LDs, suggesting a reduced adipocyte triglyceride lipase (ATGL)-mediated lipolysis. Accordingly, inhibition of lipolysis reduced lipid release from intracellular storage pools by the same magnitude as Arfrp1 depletion. Thus, the lack of Arfrp1 increases the abundance of lipolysis-modulating enzymes TERA/VCP, FAF2 and Plin2 at LDs, which might decrease lipolysis and reduce availability of fatty acids for triglyceride synthesis and their release via chylomicrons.