title: Protein mediated fatty acid uptake: synergy between CD36/FAT-facilitated transport and acyl-CoA synthetase-driven metabolism.
abstract: The mechanism of cellular fatty acid uptake is highly relevant for basic and clinical research. Previous work has demonstrated that fatty acid uptake is facilitated by cell surface membrane proteins as well as by intracellularly localized enzymes. Here, the exogenous expression of the CD36/FAT glycoprotein and the acyl-CoA synthetases FATP4 and ACSL1 in MDCK cells was quantified by comparison to recombinant proteins, and related to the corresponding increases of fatty acid uptake. At the molecular level, CD36/FAT was 30-fold more efficient than either FATP4 or ACSL1 in enhancing fatty acid uptake. Remarkably, co-expression of CD36/FAT with FATP4 or ACSL1 led to a higher increase of fatty acid uptake than expected from the combined individual contributions, whereas co-expression of FATP4 and ACSL1 did not. Immunofluorescence microscopy confirmed the plasma membrane localization of CD36/FAT and the intracellular localization of FATP4 to the endoplasmic reticulum, and of ACSL1 to mitochondria. Concluding, we suggest that fatty acid uptake in our model system is organized by two spatially distinct but synergistic mechanisms: the cell surface protein CD36/FAT directly facilitates fatty acid transport across the plasma membrane, whereas the intracellular acyl-CoA synthetases FATP4 and ACSL1 enhance fatty acid uptake indirectly by metabolic trapping.
authors: Molecular Cell Biology Laboratory, Internal Medicine IV, University of Heidelberg, Im Neuenheimer Feld 345, 69120 Heidelberg, Germany. Electronic address: hannah.schneider@gu.se.
authors: Hannah
authors: H
authors: Schneider
authors: Molecular Cell Biology Laboratory, Internal Medicine IV, University of Heidelberg, Im Neuenheimer Feld 345, 69120 Heidelberg, Germany. Electronic address: sarahstaudacher@gmx.de.
authors: Sarah
authors: S
authors: Staudacher
authors: Molecular Cell Biology Laboratory, Internal Medicine IV, University of Heidelberg, Im Neuenheimer Feld 345, 69120 Heidelberg, Germany. Electronic address: M.Poppelreuther@med.uni-heidelberg.de.
authors: Margarete
authors: M
authors: Poppelreuther
authors: Molecular Cell Biology Laboratory, Internal Medicine IV, University of Heidelberg, Im Neuenheimer Feld 345, 69120 Heidelberg, Germany. Electronic address: Wolfgang.Stremmel@med.uni-heidelberg.de.
authors: Wolfgang
authors: W
authors: Stremmel
authors: Molecular Cell Biology Laboratory, Internal Medicine IV, University of Heidelberg, Im Neuenheimer Feld 345, 69120 Heidelberg, Germany. Electronic address: re@hd-gastro.de.
authors: Robert
authors: R
authors: Ehehalt
authors: Molecular Cell Biology Laboratory, Internal Medicine IV, University of Heidelberg, Im Neuenheimer Feld 345, 69120 Heidelberg, Germany. Electronic address: Joachim.Fuellekrug@med.uni-heidelberg.de.
authors: Joachim
authors: J
authors: Füllekrug
mesh_terms: D000818:Animals; D018955:CD36 Antigens / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D003066:Coenzyme A Ligases / Q000378:metabolism*; D004285:Dogs; D050612:Fatty Acid Transport Proteins / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism*; D006801:Humans; D042541:Intracellular Space / Q000378:metabolism; D061985:Madin Darby Canine Kidney Cells; D021381:Protein Transport
chemical_list: D018955:CD36 Antigens; D050612:Fatty Acid Transport Proteins; D005227:Fatty Acids; C493571:SLC27A4 protein, human; D003066:Coenzyme A Ligases; C583414:ACSL1 protein, human
keywords: Acyl-CoA synthetases; CD36/FAT; Fatty acid uptake; Protein quantification