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

Hall, A. Rupert; Smith, Anne J.; Bernlohr, David A.

doi:10.1074/jbc.m306575200

Cited by 151 publications

(123 citation statements)

References 32 publications

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“…The lack of differences in the amount of tracer entering brain aqueous fraction, which represents products of β-oxidation (46,(67)(68)(69) (Figure 3), indicates that α-synuclein does not impact the mitochondrial pool relative to the endoplasmic reticulum pool, similar to the effect observed using 16:0 (29). Moreover, fatty acid transport protein (FATP) is associated with plasma membrane and exhibits both fatty acid transport and acyl-CoA synthetase activities (90)(91)(92) and FATP-4 is expressed in the brain (93). The potential involvement of this enzyme in acyl-CoA formation may account for the lack of differences between the groups in whole brain homogenate acyl-CoA activity and the similar incorporation coefficients for 20:4n-6 from the plasma into the total brain acyl-CoA pool.…”

Section: Discussionmentioning

confidence: 99%

Acyl-CoA Synthetase Activity Links Wild-Type but Not Mutant α-Synuclein to Brain Arachidonate Metabolism

et al. 2006

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Because α-synuclein (Snca) has a role in brain lipid metabolism, we determined the impact that the loss of α-synuclein had on brain arachidonic acid (20:4n-6) metabolism in vivo using Snca -/-mice. We measured [1-14 C]20:4n-6 incorporation and turnover kinetics in brain phospholipids using an established steady-state kinetic model. Liver was used as a negative control and no changes were observed between groups. In Snca -/-brains, there was a marked reduction in 20:4n-6-CoA mass and in microsomal acyl-CoA synthetases (Acsl) activity toward 20:4n-6. Microsomal Acsl activity was completely restored after the addition of exogenous wt mouse or human α-synuclein, but not by A30P, E46K, and A53T forms of α-synuclein. Acsl and acyl-CoA hydrolase expression was not different between groups. The incorporation and turnover of 20:4n-6 into brain phospholipid pools was markedly reduced. The dilution coefficient lambda, which indicates 20:4n-6 recycling between the acyl-CoA pool and brain phospholipids, was increased 3.3-fold, indicating more 20:4n-6 was entering the 20:4n-6-CoA pool from the plasma relative to that being recycled from the phospholipids. This is consistent with the reduction in Acsl activity observed in the Snca -/-mice. Using titration microcalorimetry, we determined that α-synuclein bound free 20:4n-6 (K d of 3.7 μM), but did not bind 20:4n-6-CoA. These data suggest α-synuclein is involved in substrate presentation to Acsl rather than product removal. In summary, our data demonstrate that α-synuclein has a major role in brain 20:4n-6 metabolism through its modulation of endoplasmic reticulum localized acyl-CoA synthetase activity, although mutants forms of α-synuclein fail to restore this activity. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript α-Synuclein is a 140 amino acid soluble protein that is highly expressed in the central nervous system (1,2) and is abundant in presynaptic terminals of neurons (1,(3)(4)(5). α-Synuclein is also found in other regions of neurons, in astrocytes, and in oligodendroglia (6-11). Overexpression of and mutations in α-synuclein are associated with early onset Parkinson's disease (12)(13)(14)(15) and other neurodegenerative diseases (16)(17)(18)(19)(20). Despite this association with neurodegenerative diseases, the physiological function of this protein remains unclear.Several lines of evidence suggest that α-synuclein can influence brain lipid metabolism. It has structural similarities to class A2 apolipoproteins (21,22) and to fatty acid binding proteins (23), suggesting that α-synuclein may alter intracellular lipid trafficking, the regulation of lipid metabolism, and may act to stabilize lipid membranes. α-Synuclein binds to small phospholipid vesicles (22,24,25) and to brain vesicles (26). Consistent with this binding, the lack of α-synuclein decreases the resting/reserve pool of synaptic vesicles (27,28). Although the direct binding of fatty acids is controversial (23,29), recent studies indicate a strong potential for an important ...

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Section: Discussionmentioning

confidence: 99%

Acyl-CoA Synthetase Activity Links Wild-Type but Not Mutant α-Synuclein to Brain Arachidonate Metabolism

et al. 2006

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“…The bacterial compound triacsin C, which had been shown to inhibit acylCoA synthetase in micromolar concentrations (38), did not prevent IL-6 induction by palmitate but, in fact, enhanced IL-6 mRNA expression significantly compared with the effect of palmitate alone. These data imply that accumulation of free palmitate because of blockade of its activation to palmitoyl-CoA results in higher IL-6 expression levels, whereas triggering the metabolism of palmitate in the presence of the unsaturated fatty acid linoleate reduces the concentration of free palmitate to ineffective levels.…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, we studied whether this conversion is required for the effect on IL-6 expression. In the presence of triacsin C, an inhibitor of acyl-CoA synthetase (38), no reduction of IL-6 mRNA expression was detected (Fig. 3C); in contrast, the effect of palmitate on IL-6 mRNA expression was almost doubled (8.3 Ϯ 0.9 versus 4.7 Ϯ 0.3).…”

Section: Activation Of Il-6 Mrna Expression By Saturated Fatty Acids mentioning

confidence: 94%

Palmitate, but Not Unsaturated Fatty Acids, Induces the Expression of Interleukin-6 in Human Myotubes through Proteasome-dependent Activation of Nuclear Factor-κB

Weigert

Brodbeck

Staiger

et al. 2004

Journal of Biological Chemistry

246

189

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Circulating interleukin-6 (IL-6), insulin, and free fatty acid (FFA) concentrations are associated with impaired insulin action in obese and type 2 diabetic individuals. However, a causal relationship between elevated plasma FFAs and IL-6 has not been shown. Because skeletal muscle represents a major target of impaired insulin action, we studied whether FFAs may affect IL-6 expression in human myotubes. We demonstrate that specifically saturated FFAs, e.g. palmitate (0.25 mM), induce IL-6 mRNA expression and protein secretion by a proteasome-dependent mechanism that leads to a rapid and chronic activation of nuclear factor-B. Insulin, high glucose concentrations, or unsaturated FFAs did not activate IL-6 expression. In fact, the unsaturated FFA linoleate inhibited palmitate-induced IL-6 production. Because inhibition of palmitate metabolism by the acyl-CoA synthetase inhibitor triacsin C did not abolish IL-6 expression, it appears that the palmitate molecule per se exerts the observed effects. Furthermore, we show that in human myotubes, IL-6 activates the phosphorylation of signal transducer and activator of transcription 3 in concentrations similar to hepatocytes. However, no inhibitory effect of IL-6 on insulin action, determined as phosphatidylinositol 3-kinase association with insulin receptor substrate-1, Akt phosphorylation, and glycogen synthesis, was detected. We conclude that IL-6 expression may be modulated by the composition of circulating FFA, e.g. by diet, and that skeletal muscle cells could be target cells for IL-6.

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“…Extracts were assayed for ACSL activity by the conversion of (29) as described by Hall, Smith, and Bernlohr (9). Briefly, samples were assayed for 2 min at pH 7.5 and 30 mM NaCl in 250 ml of a buffer containing 20 mM fatty acid delivered bound to a-cyclodextrin, 100 mM TrisHCl (pH 7.5), 10 mM ATP, 5 mM MgCl 2 , 200 mM CoA, and 200 mM dithiothreitol.…”

Section: Fatty Acsl Assaysmentioning

confidence: 99%

“…FATPs are a family of membrane-bound proteins that catalyze the ATP-dependent esterificaton of LCFAs and very LCFAs to their acyl-CoA derivatives (9). The FATPs bear 20-40% sequence identity to the long-chain ACSL class of proteins that function in long-chain acyl-CoA production.…”

mentioning

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

Cited by 151 publications

References 32 publications

Acyl-CoA Synthetase Activity Links Wild-Type but Not Mutant α-Synuclein to Brain Arachidonate Metabolism

Acyl-CoA Synthetase Activity Links Wild-Type but Not Mutant α-Synuclein to Brain Arachidonate Metabolism

Palmitate, but Not Unsaturated Fatty Acids, Induces the Expression of Interleukin-6 in Human Myotubes through Proteasome-dependent Activation of Nuclear Factor-κB

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

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