FABP1

FABP1 Full Name

fatty acid binding protein 1, liver

FABP1 Introduction

FABP1, commonly called liver fatty acid-binding protein or L-FABP, is a small, highly conserved cytosolic protein that is among the most abundant soluble proteins in hepatocytes, sometimes comprising two to five percent of the liver cell's cytoplasmic protein content. Its principal role is to bind long-chain fatty acids and other hydrophobic ligands, including lysophospholipids, cholesterol, bile acids, and certain endocannabinoids, and to ferry them through the aqueous cytosol to the organelles and enzymes that metabolize them. By solubilizing otherwise insoluble lipids, FABP1 facilitates their uptake from the blood, their transport to mitochondria, peroxisomes, and the nucleus, and their delivery to metabolic fates such as beta-oxidation, esterification into triglycerides, or signaling. The protein also engages nuclear receptors directly, notably binding and delivering ligands to peroxisome proliferator-activated receptor alpha (PPARα), a master transcriptional regulator of hepatic fatty acid catabolism, thereby coupling lipid binding to gene expression. Its unusually large binding cavity can accommodate two fatty acid molecules at once, a feature that distinguishes it from most other family members and supports high-capacity lipid buffering within the crowded cytosolic environment of the hepatocyte.

Figure 1. Putative functions of FABP in the cell. (Source: Furuhashi M, et al. 2008)

Beyond simple shuttling, FABP1 has emerged as an endogenous cytoprotectant. It buffers hepatocytes against oxidative damage, interferes with ischemia-reperfusion injury, and helps maintain liver homeostasis during fasting, infection, and inflammatory stress; its ability to bind heme and metalloporphyrins adds another layer of protection. In disease, altered FABP1 expression is linked to non-alcoholic fatty liver disease, where loss or dysregulation disturbs lipid partitioning and promotes steatosis, and the protein influences liver regeneration and may serve as a prognostic marker for hepatic surgery. More recently, FABP1 was identified as the major cytosolic chaperone for endocannabinoids such as anandamide and 2-arachidonoylglycerol, shaping their intracellular hydrolysis and accumulation in response to diet or cannabinoid exposure. Collectively, FABP1 exemplifies how a compact binding protein can integrate lipid uptake, metabolism, signaling, and cellular defense into a single coordinated hepatic program.

Alternate Names for FABP1

FABP1; fatty acid binding protein 1, liver; FABPL; L-FABP; fatty acid-binding protein, liver; fatty acid-binding protein 1; liver-type fatty acid-binding protein;

• 1. Furuhashi M, et al. Fatty acid-binding proteins: role in metabolic diseases and potential as drug targets. Nat Rev Drug Discov. 2008 Jun;7(6):489-503.
  2. Wang G, et al. Recent insights into the biological functions of liver fatty acid binding protein 1. J Lipid Res. 2015 Dec;56(12):2238-47.