Insulin activates intracellular transport of lipid droplets to release triglycerides from the liver. Academic Article uri icon

Overview

abstract

  • Triglyceride-rich lipid droplets (LDs) are catabolized with high efficiency in hepatocytes to supply fatty acids for producing lipoprotein particles. Fasting causes a massive influx of adipose-derived fatty acids into the liver. The liver in the fasted state is therefore bloated with LDs but, remarkably, still continues to secrete triglycerides at a constant rate. Here we show that insulin signaling elevates phosphatidic acid (PA) dramatically on LDs in the fed state. PA then signals to recruit kinesin-1 motors, which transport LDs to the peripherally located smooth ER inside hepatocytes, where LDs are catabolized to produce lipoproteins. This pathway is down-regulated homeostatically when fasting causes insulin levels to drop, thus preventing dangerous elevation of triglycerides in the blood. Further, we show that a specific peptide against kinesin-1 blocks triglyceride secretion without any apparent deleterious effects on cells. Our work therefore reveals fundamental mechanisms that maintain lipid homeostasis across metabolic states and leverages this knowledge to propose a molecular target against hyperlipidemia.

publication date

  • October 11, 2019

Research

keywords

  • Insulin
  • Lipid Droplets
  • Liver
  • Triglycerides

Identity

PubMed Central ID

  • PMC6829650

Scopus Document Identifier

  • 85074551264

Digital Object Identifier (DOI)

  • 10.1016/j.cmet.2008.12.013

PubMed ID

  • 31604801

Additional Document Info

volume

  • 218

issue

  • 11