Molecular Basis for Regulation of Mammalian Fatty Acid Synthase

Abstract

De novo lipogenesis (DNL) is an essential metabolic process that converts excess cellular glucose to fatty acids. Fatty Acid Synthase (FASN) is a key enzyme in the DNL pathway and has shown promising pre‐clinical results as a therapeutic target in a variety of metabolic diseases, including cancer, non‐alcoholic fatty liver disease (NAFLD), and most recently COVID‐19. Mammalian FASN is a large multifunctional enzyme with 6 catalytic domains and a flexibly tethered acyl carrier protein (ACP). The ACP shuttles covalently linked intermediates between catalytic domains to facilitate palmitate synthesis. Previous negative stain electron microscopy data has shown that mammalian FASN is a dynamic enzyme that adopts multiple conformations in solution, but the role of these conformational dynamics in the mechanism of FASN is yet to be determined. To understand how the conformational dynamics of mammalian FASN contribute to the overall mechanism and its’ regulation, we have generated multiple constructs and characterized their enzymatic activity using diverse biochemical assays. Additionally, we have made progress towards understanding the enzyme dynamics using Hydrogen‐Deuterium Exchange Mass Spectrometry (HDX‐MS). We are actively pursuing structural studies to implement an integrative approach towards advancing our understanding of the complex mechanism of mammalian FASN.