Cellular responses to excess fatty acids: Focus on ubiquitin regulatory X domain-containing protein 8

PURPOSE OF REVIEW: Although fatty acids are crucial for cell survival, their overaccumulation triggers lipotoxicity that leads to metabolic syndrome. Thus, cells maintain their homeostasis by multiple feedback regulatory systems. This review focuses on how cells regulate the level of fatty acids by these systems. RECENT FINDINGS: Ubiquitin regulatory X domain-containing protein 8 has been identified as a specific sensor for unsaturated fatty acids that regulates lipogenic activity. SUMMARY: Together with the previously identified peroxisome proliferator-activated receptors and liver X receptor, these proteins sense the presence of unsaturated fatty acids and initiate reactions preventing their overaccumulation. Understanding the mechanism of the signal transduction pathways mediated by these proteins may offer new strategies to treat metabolic syndrome.