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Novel role of FATP1 in mitochondrial fatty acid oxidation in skeletal muscle cells.

Sebastián D, Guitart M, García-Martínez C, Mauvezin C, Orellana-Gavaldà JM, Serra D, Gómez-Foix AM, Hegardt FG, Asins G - J. Lipid Res. (2009)

Bottom Line: The cooverexpression of FATP1 and CPT1 also enhanced mitochondrial fatty acid oxidation, similar to the cooverexpression of FAT/CD36 and CPT1.However, etomoxir, an irreversible inhibitor of CPT1, blocked all these effects.These data reveal that FATP1, like FAT/CD36, is associated with mitochondria and has a role in mitochondrial oxidation of fatty acids.

View Article: PubMed Central - PubMed

Affiliation: Departments of Biochemistry and Molecular Biology, School of Pharmacy, University of Barcelona, Barcelona, Spain.

ABSTRACT
Carnitine palmitoyltransferase 1 (CPT1) catalyzes the first step in long-chain fatty acid import into mitochondria, and it is believed to be rate limiting for beta-oxidation of fatty acids. However, in muscle, other proteins may collaborate with CPT1. Fatty acid translocase/CD36 (FAT/CD36) may interact with CPT1 and contribute to fatty acid import into mitochondria in muscle. Here, we demonstrate that another membrane-bound fatty acid binding protein, fatty acid transport protein 1 (FATP1), collaborates with CPT1 for fatty acid import into mitochondria. Overexpression of FATP1 using adenovirus in L6E9 myotubes increased both fatty acid oxidation and palmitate esterification into triacylglycerides. Moreover, immunocytochemistry assays in transfected L6E9 myotubes showed that FATP1 was present in mitochondria and coimmunoprecipitated with CPT1 in L6E9 myotubes and rat skeletal muscle in vivo. The cooverexpression of FATP1 and CPT1 also enhanced mitochondrial fatty acid oxidation, similar to the cooverexpression of FAT/CD36 and CPT1. However, etomoxir, an irreversible inhibitor of CPT1, blocked all these effects. These data reveal that FATP1, like FAT/CD36, is associated with mitochondria and has a role in mitochondrial oxidation of fatty acids.

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Protein expression levels of CPT1A, FATP1, and FAT/CD36 in L6E9 myotubes. Western blot for CPT1A, FATP1, and FAT/CD36 proteins was performed in 50 μg of mitochondrial fractions obtained from cells infected with Ad-LacZ, Ad-CPT1A, Ad-FATP1, and Ad-FAT/CD36. Western blot against porin was used as a mitochondrial loading control.
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fig5: Protein expression levels of CPT1A, FATP1, and FAT/CD36 in L6E9 myotubes. Western blot for CPT1A, FATP1, and FAT/CD36 proteins was performed in 50 μg of mitochondrial fractions obtained from cells infected with Ad-LacZ, Ad-CPT1A, Ad-FATP1, and Ad-FAT/CD36. Western blot against porin was used as a mitochondrial loading control.

Mentions: Increased fatty acid uptake has been shown to increase transcription of CPT1 via a peroxisome proliferator-activated receptor (PPAR)-dependent pathway (28). To assess the possibility that the increase in fatty acid oxidation was due to increased expression of CPT1 in cells overexpressing FATP1 as a consequence of an increased influx of fatty acids, we performed a Western blot for CPT1 in L6E9 myotubes. CPT1 protein levels were increased in cells overexpressing CPT1 but not in those cells overexpressing FATP1 or FAT/CD36 (Fig. 5). Indeed, the overexpression of FATP1, FAT/CD36, or CPT1 only affected the expression of the protein that had been overexpressed but not the other proteins studied (Fig. 5).


Novel role of FATP1 in mitochondrial fatty acid oxidation in skeletal muscle cells.

Sebastián D, Guitart M, García-Martínez C, Mauvezin C, Orellana-Gavaldà JM, Serra D, Gómez-Foix AM, Hegardt FG, Asins G - J. Lipid Res. (2009)

Protein expression levels of CPT1A, FATP1, and FAT/CD36 in L6E9 myotubes. Western blot for CPT1A, FATP1, and FAT/CD36 proteins was performed in 50 μg of mitochondrial fractions obtained from cells infected with Ad-LacZ, Ad-CPT1A, Ad-FATP1, and Ad-FAT/CD36. Western blot against porin was used as a mitochondrial loading control.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2724792&req=5

fig5: Protein expression levels of CPT1A, FATP1, and FAT/CD36 in L6E9 myotubes. Western blot for CPT1A, FATP1, and FAT/CD36 proteins was performed in 50 μg of mitochondrial fractions obtained from cells infected with Ad-LacZ, Ad-CPT1A, Ad-FATP1, and Ad-FAT/CD36. Western blot against porin was used as a mitochondrial loading control.
Mentions: Increased fatty acid uptake has been shown to increase transcription of CPT1 via a peroxisome proliferator-activated receptor (PPAR)-dependent pathway (28). To assess the possibility that the increase in fatty acid oxidation was due to increased expression of CPT1 in cells overexpressing FATP1 as a consequence of an increased influx of fatty acids, we performed a Western blot for CPT1 in L6E9 myotubes. CPT1 protein levels were increased in cells overexpressing CPT1 but not in those cells overexpressing FATP1 or FAT/CD36 (Fig. 5). Indeed, the overexpression of FATP1, FAT/CD36, or CPT1 only affected the expression of the protein that had been overexpressed but not the other proteins studied (Fig. 5).

Bottom Line: The cooverexpression of FATP1 and CPT1 also enhanced mitochondrial fatty acid oxidation, similar to the cooverexpression of FAT/CD36 and CPT1.However, etomoxir, an irreversible inhibitor of CPT1, blocked all these effects.These data reveal that FATP1, like FAT/CD36, is associated with mitochondria and has a role in mitochondrial oxidation of fatty acids.

View Article: PubMed Central - PubMed

Affiliation: Departments of Biochemistry and Molecular Biology, School of Pharmacy, University of Barcelona, Barcelona, Spain.

ABSTRACT
Carnitine palmitoyltransferase 1 (CPT1) catalyzes the first step in long-chain fatty acid import into mitochondria, and it is believed to be rate limiting for beta-oxidation of fatty acids. However, in muscle, other proteins may collaborate with CPT1. Fatty acid translocase/CD36 (FAT/CD36) may interact with CPT1 and contribute to fatty acid import into mitochondria in muscle. Here, we demonstrate that another membrane-bound fatty acid binding protein, fatty acid transport protein 1 (FATP1), collaborates with CPT1 for fatty acid import into mitochondria. Overexpression of FATP1 using adenovirus in L6E9 myotubes increased both fatty acid oxidation and palmitate esterification into triacylglycerides. Moreover, immunocytochemistry assays in transfected L6E9 myotubes showed that FATP1 was present in mitochondria and coimmunoprecipitated with CPT1 in L6E9 myotubes and rat skeletal muscle in vivo. The cooverexpression of FATP1 and CPT1 also enhanced mitochondrial fatty acid oxidation, similar to the cooverexpression of FAT/CD36 and CPT1. However, etomoxir, an irreversible inhibitor of CPT1, blocked all these effects. These data reveal that FATP1, like FAT/CD36, is associated with mitochondria and has a role in mitochondrial oxidation of fatty acids.

Show MeSH
Related in: MedlinePlus