Functional Analysis of Mammalian Soluble Lipid Binding Proteins

FALOMIR LOCKHART, LJ; FRANCHINI GR; DE GERÓNIMO E; GUERBI, MX; RODRIGUEZ SAWICKI, L; BOTTASSO, N; CÓRSICO B

LANAIS-PRO, Departamento de Química Biológica, Facultad de Farmacia y Bioquímica (UBA)

Jornada; Herramientas Modernas para el Estudio de Aspectos Estructurales de Proteínas; 2009

The evolution of different families of intracellular soluble lipid binding proteins (SLBP) may be connected to the wide range of functions attributed to lipids as well as their low solubility in the cellular media. Among these SLBP, the mammalian fatty acid binding proteins (FABP) are ubiquitously produced. The large number of FABP types and the distinct expression pattern of each of them suggest overlapping as well as distinct functions in specific tissues; based on specific structural elements. Structure-function studies indicate that subtle conformational changes that occur upon ligand binding may promote distinct FABP-protein or FABP-membrane interactions that could define their specificity.We used a combination of in vitro and in cell studies to assess the differential functionality of abundantly coexpressed FABP in the enterocyte. First, the use of several structural variants highlighted the importance of the helical region and specific residues have been identified in the Portal Domain, crucial for ligand transport and membrane binding properties of FABP. On the other hand, modification of their expression in culture cells has an impact on several cellular processes, mainly lipid metabolism but also cell proliferation and differentiation. FABPs’ participation in regulating fatty acid metabolism, may ultimately impact on systemic metabolism.