Regulation of fatty acid binding protein 5 (FABP5) by lipids

In western diet, lipids represent more than 40% of the caloric intake. They are used either as an energy source or as building blocks for membranes. Several studies have shown that lipids act also as signaling molecules. Interestingly, although the gut is responsible for fat absorption and also has an endocrine role, little is known how these two processes are correlated. The Fatty Acid Binding Protein 5 (FABP5) is a member of the highly conserved FABP family, which work as carrier-proteins involved in the uptake of the Long-Chain Fatty Acids (LCFAs) and other hydrophobic ligands. FABP5 is present in several tissues including duodenal K cells. It has been related to Gastric Inhibitory Polypeptide (GIP) release and to progression and development of cancer and metabolic syndrome.

The aim of my PhD thesis is to shed light on the molecular mechanism of LCFAs on GIP secretion and membrane remodeling. Therefore, to study in a comprehensive way, the impact of LCFAs on GIP secretion, human, full-length FABP5 was expressed and purified from E. coli.  After a detailed biochemical characterisation, this protein will be used in fatty acids’ binding assays. In parallel, an enteroendocrine cell model line (STC-1) will be used to study LCFAs impact on cellular membrane remodelling (lipidomics) in conjunction with GIP secretion assay.

This work can guide us to a better understanding of the role of FABP5 on cellular membrane remodeling and the capacity of different LCFAs to mediate a hormone secretory outcome.