About FABP / Fatty Acid-Binding Protein:
FABPs come in a 10- strand antiparallel β-barrel form and each one creates hydrogen bonds with the following strand in an up and down manner. The first five and the second five strands make orthogonal sheets and form a level barrel that is shut at one end and has a helix-turn-helix motif between β-strands 1 and 2 at the other end.
Fatty Acid-Binding Protein interaction
FABPs are capable of interacting directly with CD36. For example, FABP1 changes the plasma membrane's lipid make-up by enabling sterol uptake, thereby increasing fluidity. They can also moderate the uptake of fatty acids in various tissues. FABP 4 and FABP 5 have been shown to aid the import of fatty acids into the heart.
FABPs deliver lipids to nuclear receptors such as Peroxisome Proliferator-Activated Receptors (PPARs) to help moderate transcriptional programs. However, this mechanism is unique to each FABP class and PPAR isoform. For instance, FABP1 aids free fatty acid uptake into the cytoplasm and mediates their delivery into the nucleus. FABP5 can also deliver retinoic acid to PPAR β/δ for neuronal development. It also aids in endocannabinoid anandamide hydrolysis into PPAR β/δ ligands, thereby controlling hippocampal function. FABP4 interacts with and delivers ligands to PPARϓ, although its operations are yet to be deciphered.
Functions of Fatty Acid-Binding Protein
FABPs aid the solubilizing and transporting of lipids. They also coordinate the metabolism and responses in the tissues and organs across various species. Additionally, they interact with several membranes and intracellular proteins such as the Hormone Sensitive Lipase (HSL) and Peroxisome Proliferator-Activated Receptors (PPARs). They also control cellular and tissue-specific lipids' responses and carry out pleiotropic functions to sustain tissue homeostasis in health and aid in disease pathogenesis.
FABPs are also involved in several physiological occurrences in cells, such as facilitating β-oxidation in mitochondria, the cell membrane's production in the endoplasmic reticulum, and other enzymatic activities in the cytosol. Various studies have shown that they can prove useful in developing preventive and therapeutic agents for other diseases.