title: Different functions of intestinal and liver-type fatty acid-binding proteins in intestine and in whole body energy homeostasis.
abstract: It has long been known that mammalian enterocytes coexpress two members of the fatty acid-binding protein (FABP) family, the intestinal FABP (IFABP) and the liver FABP (LFABP). Both bind long-chain fatty acids and have similar though not identical distributions in the intestinal tract. While a number of in vitro properties suggest the potential for different functions, the underlying reasons for expression of both proteins in the same cells are not known. Utilizing mice genetically lacking either IFABP or LFABP, we directly demonstrate that each of the enterocyte FABPs participates in specific pathways of intestinal lipid metabolism. In particular, LFABP appears to target fatty acids toward oxidative pathways and dietary monoacylglycerols toward anabolic pathways, while IFABP targets dietary fatty acids toward triacylglycerol synthesis. The two FABP-null models also displayed differences in whole body response to fasting, with LFABP-null animals losing less fat-free mass and IFABP-null animals losing more fat mass relative to wild-type mice. The metabolic changes observed in both null models appear to occur by nontranscriptional mechanisms, supporting the hypothesis that the enterocyte FABPs are specifically trafficking their ligands to their respective metabolic fates.
authors.affiliation: Department of Nutritional Sciences, Rutgers, the State University of New Jersey, New Brunswick, USA.
authors.forename: William Stacy
authors.initials: WS
authors.lastname: Lagakos
authors.forename: Angela Marie
authors.initials: AM
authors.lastname: Gajda
authors.forename: Luis
authors.initials: L
authors.lastname: Agellon
authors.forename: Bert
authors.initials: B
authors.lastname: Binas
authors.forename: Victor
authors.initials: V
authors.lastname: Choi
authors.forename: Bernadette
authors.initials: B
authors.lastname: Mandap
authors.forename: Timothy
authors.initials: T
authors.lastname: Russnak
authors.forename: Yin Xiu
authors.initials: YX
authors.lastname: Zhou
authors.forename: Judith
authors.initials: J
authors.lastname: Storch
mesh_terms: D000818:Animals; D015153:Blotting, Western; D001823:Body Composition / Q000235:genetics / Q000502:physiology; D001835:Body Weight / Q000235:genetics / Q000502:physiology; D004435:Eating / Q000235:genetics / Q000502:physiology; D004734:Energy Metabolism / Q000502:physiology*; D020895:Enterocytes / Q000378:metabolism; D050556:Fatty Acid-Binding Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D005227:Fatty Acids / Q000378:metabolism; D005243:Feces / Q000737:chemistry; D015870:Gene Expression / Q000502:physiology; D005838:Genotype; D006706:Homeostasis / Q000502:physiology; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000502:physiology*; D050356:Lipid Metabolism / Q000235:genetics / Q000502:physiology; D008055:Lipids / Q000097:blood; D008099:Liver / Q000378:metabolism* / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010084:Oxidation-Reduction
chemical_list: D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids; D008055:Lipids