FATP1 channels exogenous FA into 1,2,3-triacyl-sn-glycerol and down-regulates sphingomyelin and cholesterol metabolism in growing 293 cells

Hatch, Grant M.; Smith, Anne J.; Xu, Fred Y.; Hall, A. Rupert; Bernlohr, David A.

doi:10.1194/jlr.m200130-jlr200

Cited by 74 publications

(64 citation statements)

References 44 publications

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“…For example, overexpressing FATP1 in HEK293 cells alters partitioning of both exogenously added oleic acid and FA synthesized de novo from acetate into cellular lipids and increases cellular TAG content while decreasing cholesterol and sphingomyelin content [41]. In skeletal muscle, adenovirus-mediated overexpression of FATP1 increases the partitioning of oleate or palmitate into TAG and away from β-oxidation [18], and overexpression in mouse heart increases FA uptake and TAG content and causes a lipotoxic cardiomyopathy [42].…”

Section: Role Of Acyl-coa Synthetases In Fa Channelingmentioning

confidence: 99%

Long-Chain Acyl-Coa Synthetases And Fatty Acid Channeling

2007

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Thirteen homologous proteins comprise the long-chain acyl-CoA synthetase (ACSL), fatty acid transport protein (FATP), and bubblegum (ACSBG) subfamilies that activate long-chain and verylong-chain fatty acids to form acyl-CoAs. Gain-and loss-of-function studies show marked differences in the ability of these enzymes to channel fatty acids into different pathways of complex lipid synthesis. Further, the ability of the ACSLs and FATPs to enhance cellular FA uptake does not always require these proteins to be present on the plasma membrane; instead, FA uptake can be increased by enhancing its conversion to acyl-CoA and its metabolism in downstream pathways. Since altered fatty acid metabolism is a hallmark of numerous metabolic diseases and pathological conditions, the ACSL, FATP and ACSBG isoforms are likely to play important roles in disease etiology. A family of acyl-CoA synthetases activates intracellular long-chain fatty acidsBefore a fatty acid (FA) from an exogenous or endogenous source can enter any metabolic pathway with the exception of eicosanoid metabolism, it must first be activated to form an acyl-CoA. This activation step is catalyzed by acyl-CoA synthetase (ACS) via a two-step reaction: 1) the formation of an intermediate fatty acyl-AMP with the release of pyrophosphate, and 2) the formation of a fatty acyl-CoA with the release of AMP.The ACS family is comprised of at least 25 members [1]. Although overlap exists, ACS family members are broadly classified by their substrate specificities for FAs of varying chain length. This review will focus on the three subfamilies of ACS enzymes that activate long-chain and/ or very-long-chain saturated and unsaturated FAs, long-chain ACSs (ACSL), very-long-chain ACSs (FATP), and bubblegum (ACSBG) isoforms [2].The ACSL, FATP and ACSBG families include multiple isoforms, each encoded by a separate gene (Tables 1, 2). Additionally, splice variants of ACSL isoforms have been identified in both humans and rodents [3]. ACS enzymes share significant amino acid sequence similarity, particularly in two highly conserved regions, a putative ATP-AMP signature motif for ATP binding and a motif for FA binding [4]. Despite these similarities, purified ACSL and FATP isoforms and their splice variants show distinct enzyme kinetics, differences in sensitivity to inhibitors ( Role of acyl-CoA synthetases in FA channelingThe existence of 13 ACSL, FATP and ACSBG isoforms that all activate long-chain FA has suggested that each has an independent role in channeling FA within cells. Unique roles for ACS isoforms were first identified in studies of Saccharomyces cerevisiae mutants that lacked the ACS isoforms Faa1 and Faa4, and were unable to use exogenously provided fatty acids [31]. Similarly, complementation studies of ACS-deficient E. coli showed that each of the 5 rat ACSL isoforms differs in its ability to channel FA into specific pathways like phospholipid synthesis and β-oxidation [32]. The ACSL and FATP isoforms also differ in their ability to complement FA uptake and a...

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Section: Role Of Acyl-coa Synthetases In Fa Channelingmentioning

confidence: 99%

Long-Chain Acyl-Coa Synthetases And Fatty Acid Channeling

2007

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“…HEK-293 cells are an excellent model system to evaluate FATP4 function in lipid metabolism because they are a well-defined cell system, grow easily in culture, and have been shown to tolerate FATP expression (12). Dilutions of the electroporated cells were plated in DMEM containing 10% FBS and incubated at 37jC and 5% CO 2 .…”

Section: Generation Of Stable Hek-293 Cells Expressing Fatp4mentioning

confidence: 99%

“…Evidence for the role of FATPs in fatty acid transport has been qualitatively evaluated by various loss-of-function/gain-offunction model systems. Stable HEK-293 cell lines over-expressing murine FATP1 demonstrate increased LCFA uptake and triacylglycerol accumulation (12). A transgenic mouse model with cardiac-specific expression of FATP1 demonstrated increased myocardial LCFA uptake (13).…”

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confidence: 99%

Fatty acid metabolism in adipocytes: functional analysis of fatty acid transport proteins 1 and 4

Lobo

Wiczer

Smith

et al. 2007

Journal of Lipid Research

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129

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The role of fatty acid transport protein 1 (FATP1) and FATP4 in facilitating adipocyte fatty acid metabolism was investigated using stable FATP1 or FATP4 knockdown (kd) 3T3-L1 cell lines derived from retrovirus-delivered short hairpin RNA (shRNA). Decreased expression of FATP1 or FATP4 did not affect preadipocyte differentiation or the expression of FATP1 (in FATP4 kd), FATP4 (in FATP1 kd), fatty acid translocase, acyl-coenzyme A synthetase 1, and adipocyte fatty acid binding protein but did lead to increased levels of peroxisome proliferator-activated receptor g and CCAAT/enhancer binding protein a. Both FATP1 and FATP4 kd adipocytes exhibited reduced triacylglycerol deposition and corresponding reductions in diacylglycerol and monoacylglycerol levels compared with control cells. FATP1 kd adipocytes displayed an ?25% reduction in basal 3 H-labeled fatty acid uptake and a complete loss of insulin-stimulated 3 H-labeled fatty acid uptake compared with control adipocytes. In contrast, FATP4 kd adipocytes as well as HEK-293 cells overexpressing FATP4 did not display any changes in fatty acid influx. FATP4 kd cells exhibited increased basal lipolysis, whereas FATP1 kd cells exhibited no change in lipolytic capacity. Consistent with reduced triacylglycerol accumulation, FATP1 and FATP4 kd adipocytes exhibited enhanced 2-deoxyglucose uptake compared with control adipocytes. These findings define unique and distinct roles for FATP1 and FATP4 in adipose fatty acid metabolism.

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“…However, studies in crude cellular extracts suggested that FATP1 may not be similarly affected (14). To test whether triacsin C inhibits purified FATP1, various concentrations were added to the standard reaction mixture (Fig.…”

Section: Fatp1 Acyl-coa Synthetase Activitymentioning

confidence: 99%

“…FATP1 contains two functional motifs: motif 1, which contains a putative site for the binding of ATP (via serine 250) that is part of the acyl-CoA synthetase reaction mechanism, and motif 2, which is proposed to be a ligand (fatty acid) binding domain (11)(12)(13). Overexpression of FATP1 in human embryonic kidney 293 cells results in an increased rate of fatty acid influx for both C18:1 and C24:0, which are channeled to triacylglycerol biosynthesis (14). As such, fatty acid transport protein 1 has been proposed to be a bifunctional protein capable of facilitating transbilayer movement of fatty acids and their metabolic activation (esterification) with coenzyme A.…”

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confidence: 99%

Characterization of the Acyl-CoA Synthetase Activity of Purified Murine Fatty Acid Transport Protein 1

Hall

Smith

Bernlohr

2003

Journal of Biological Chemistry

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Fatty acid transport protein 1 (FATP1) is an ϳ63-kDa plasma membrane protein that facilitates the influx of fatty acids into adipocytes as well as skeletal and cardiac myocytes. Previous studies with FATP1 expressed in COS1 cell extracts suggested that FATP1 exhibits very long chain acyl-CoA synthetase (ACS) activity and that such activity may be linked to fatty acid transport. To address the enzymatic activity of the isolated protein, murine FATP1 and ACS1 were engineered to contain a C-terminal Myc-His tag expressed in COS1 cells via adenoviral-mediated infection and purified to homogeneity using nickel affinity chromatography. Kinetic analysis of the purified enzymes was carried out for long chain palmitic acid (C16:0) and very long chain lignoceric acid (C24:0) as well as for ATP and CoA. FATP1 exhibited similar substrate specificity for fatty acids 16 -24 carbons in length, whereas ACS1 was 10-fold more active on long chain fatty acids relative to very long chain fatty acids. The very long chain acyl-CoA synthetase activity of the two enzymes was comparable as were the K m values for both ATP and coenzyme A. Interestingly, FATP1 was insensitive to inhibition by triacsin C, whereas ACS1 was inhibited by micromolar concentrations of the compound. These data represent the first characterization of purified FATP1 and indicate that the enzyme is a broad substrate specificity acyl-CoA synthetase. These findings are consistent with the hypothesis that that fatty acid uptake into cells is linked to their esterification with coenzyme A.

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FATP1 channels exogenous FA into 1,2,3-triacyl-sn-glycerol and down-regulates sphingomyelin and cholesterol metabolism in growing 293 cells

Cited by 74 publications

References 44 publications

Long-Chain Acyl-Coa Synthetases And Fatty Acid Channeling

Long-Chain Acyl-Coa Synthetases And Fatty Acid Channeling

Fatty acid metabolism in adipocytes: functional analysis of fatty acid transport proteins 1 and 4

Characterization of the Acyl-CoA Synthetase Activity of Purified Murine Fatty Acid Transport Protein 1

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