Liver fatty acid binding protein (L-FABP) partipates in different cell processes in the enterocyte.

LISANDRO J. FALOMIR-LOCKART; LUCIANA RODRIGUEZ SAWICKI; GISELA R. FRANCHINI; BETINA CÓRSICO

Tucumán

Congreso; XLV Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2009

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Introduction: Intestinal enterocytes express large concentrations of two homologous fattyacid binding proteins (FABPs): intestinal FABP (IFABP) (15.1 kDa) and liver FABP (LFABP)(14.2 kDa). It has long been hypothesized that FABPs participate in the intracellulartransport and processing of the large quantities of fatty acids (FA) absorbed by theintestine, but their specific function are still poorly understood. In particular, it is currentlynot known why a single cell type contains two distinct types of FABP.Objective: We expect to identify the interaction partners of intestinal FABPs in order todescribe the molecular crosstalk relevant for its biological functions.Methods: In this work, we took advantage of different structural variants of intestinalFABPs and a battery of biochemical and biophysical methodologies to analyze itsinteraction with membranes and other proteins. Tb/DPA complex leakage, sucrose vesiclesbinding, Cyt c competition assay and radiolabeled photoactivable phospholipid wereemployed to study different factors (vesicle curvature, ligand nature, lipid composition, etc)that modulate the interaction of FABPs with artificial model membranes. On the other hand,a fluorescence based assay were employed to analyze colisional transfer of fatty acidanalogs between IFABP and LFABP in a stopped-flow module.Results: Lipid composition and ligand binding show strong changes in membraneinteraction properties of IFABP and LFABP, as evidenced by different techniques.Collisional transfer of fluorescent fatty acids suggests functional interaction between theseintestinal FABPs.Conclusions: Intestinal FABPs could interact differentially with each other and withsubcellular membranous fractions accordingly with ligand binding. The results in vitropresented here may reflect in vivo functions of intestinal FABPs. Increasing evidencesupports the idea that FABPs participate and modulate several cell functions and furtherstudies will be needed.