Enterocyte fatty acid-binding proteins (FABPs): Different functions of liver and intestinal FABPs in the intestine

Abstract

SUMMARY Fatty acid binding proteins (FABP) are highly abundant cytosolic proteins that are expressed in most mammalian tissues. In the intestinal enterocyte, both Liver- (LFABP; FABP1) and Intestinal-fatty acid binding proteins (IFABP; FABP2) are expressed. These proteins display high affinity binding for long chain fatty acids (FA) and other hydrophobic ligands, thus they are believed to be involved with uptake and trafficking of lipids in the intestine. In vitro studies have identified differences in ligand binding stoichiometry and specificity, and in mechanisms of FA transfer to membranes, and it has been hypothesized that LFABP and IFABP have difference functions in the enterocyte. Studies directly comparing LFABP- and IFABP-null mice have revealed markedly different phenotypes, indicating that these proteins indeed have different functions in intestinal lipid metabolism and whole body energy homeostasis. In this review, we discuss the evolving knowledge of the functions of LFABP and IFABP in the intestinal enterocyte.

Biomarkers of Environmental Enteropathy are Positively Associated with Immune Responses to an Oral Cholera Vaccine in Bangladeshi Children

“…Intestinal Fatty Acid-Binding Protein 2 (i-FABP2) is mostly expressed in intestinal enterocytes [29], and studies have shown that i-FABP2 is an indicator of enterocyte damage and is associated with intestinal inflammation [30]. i-FABP2 is also involved in cell repair and proliferation [31,32] that may play crucial roles in immune responses to vaccines.…”

Fatty acid binding proteins have the potential to channel dietary fatty acids into enterocyte nuclei

“…Axial patterning of FABP expression has been attributed to ligand and absorption specifi cities along the digestive track ( 58 ), but, in other cases, overlapping FABP expression sites and ligand binding specifi cities may represent a mechanism for ensuring functional redundancy. Studies directly comparing FABP1 -and FABP2 -null mice have revealed markedly different phenotypes, indicating that the encoded proteins indeed have different functions in the intestinal lipid metabolism and whole body energy homeostasis ( 13,63,64 ).…”

Genetic Variations Associated with Vitamin A Status and Vitamin A Bioavailability

“…This intracellular transport protein could also be beta-carotene oxygenase 2 (BCO2), although it is apparently mainly located in mitochondria [44]. The intracellular βC transporter could also be a fatty acid binding protein (FABP), more likely liver FABP (L-FABP), which is also present in the intestine and which displays high-affinity binding for various hydrophobic ligands [45]. At this step, it is important to make clear that only a fraction of absorbed βC is metabolized in the enterocyte.…”