CPT 1C is localized in endoplasmic reticulum of neurons and has carnitine palmitoyltransferase activity

CPT1c is a carnitine palmitoyltransferase 1 (CPT1) isoform that is expressed only in the brain. The enzyme has recently been localized in neuron mitochondria. Although it has high sequence identity with the other two CPT1 isoenzymes (a and b), no CPT activity has been detected to date. Our results i...

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Autores: Sierra, Adriana Y., Gratacós, Esther, Carrasco, Patricia, Clotet, Josep, Ureña, Jesús, Serra i Cucurull, Dolors, Asins Muñoz, Guillermina, Hegardt, Fausto, Casals i Farré, Núria
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2008
País:España
Institución:Universidad de Barcelona
Repositorio:Dipòsit Digital de la UB
OAI Identifier:oai:diposit.ub.edu:2445/223479
Acceso en línea:https://hdl.handle.net/2445/223479
Access Level:acceso abierto
Palabra clave:Catàlisi
Carnitina palmitoïl-transferasa 1
Animals
Àcids grassos
Catalysis
Carnitine palmitoyltransferase I
Fatty acids
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spelling CPT 1C is localized in endoplasmic reticulum of neurons and has carnitine palmitoyltransferase activitySierra, Adriana Y.Gratacós, EstherCarrasco, PatriciaClotet, JosepUreña, JesúsSerra i Cucurull, DolorsAsins Muñoz, GuillerminaHegardt, FaustoCasals i Farré, NúriaCatàlisiCarnitina palmitoïl-transferasa 1AnimalsÀcids grassosCatalysisCarnitine palmitoyltransferase IAnimalsFatty acidsCPT1c is a carnitine palmitoyltransferase 1 (CPT1) isoform that is expressed only in the brain. The enzyme has recently been localized in neuron mitochondria. Although it has high sequence identity with the other two CPT1 isoenzymes (a and b), no CPT activity has been detected to date. Our results indicate that CPT1c is expressed in neurons but not in astrocytes of mouse brain sections. Overexpression of CPT1c fused to the green fluorescent protein in cultured cells demonstrates that CPT1c is localized in the endoplasmic reticulum rather than mitochondria and that the N-terminal region of CPT1c is responsible for endoplasmic reticulum protein localization. Western blot experiments with cell fractions from adult mouse brain corroborate these results. In addition, overexpression studies demonstrate that CPT1c does not participate in mitochondrial fatty acid oxidation, as would be expected from its subcellular localization. To identify the substrate of CPT1c enzyme, rat cDNA was overexpressed in neuronal PC-12 cells, and the levels of acylcarnitines were measured by high-performance liquid chromatography-mass spectrometry. Palmitoylcarnitine was the only acylcarnitine to increase in transfected cells, which indicates that palmitoyl-CoA is the enzyme substrate and that CPT1c has CPT1 activity. Microsomal fractions of PC-12 and HEK293T cells overexpressing CPT1c protein showed a significant increase in CPT1 activity of 0.57 and 0.13 nmol.mg(-1).min(-1), respectively, which is approximately 50% higher than endogenous CPT1 activity. Kinetic studies demonstrate that CPT1c has similar affinity to CPT1a for both substrates but 20-300 times lower catalytic efficiency.American Society for Biochemistry and Molecular Biology2008info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionapplication/pdfhttps://hdl.handle.net/2445/223479Articles publicats en revistes (Infermeria Fonamental i Clínica)reponame:Dipòsit Digital de la UBinstname:Universidad de BarcelonaInglésReproducció del document publicat a: https://doi.org/10.1074/jbc.M707965200Journal of Biological Chemistry, 2008, vol. 283, num.11, p. 6878-6885https://doi.org/10.1074/jbc.M707965200cc by (c) Sierra, Adriana Y. et al., 2008info:eu-repo/semantics/openAccessoai:diposit.ub.edu:2445/2234792026-05-27T06:46:51Z
dc.title.none.fl_str_mv CPT 1C is localized in endoplasmic reticulum of neurons and has carnitine palmitoyltransferase activity
title CPT 1C is localized in endoplasmic reticulum of neurons and has carnitine palmitoyltransferase activity
spellingShingle CPT 1C is localized in endoplasmic reticulum of neurons and has carnitine palmitoyltransferase activity
Sierra, Adriana Y.
Catàlisi
Carnitina palmitoïl-transferasa 1
Animals
Àcids grassos
Catalysis
Carnitine palmitoyltransferase I
Animals
Fatty acids
title_short CPT 1C is localized in endoplasmic reticulum of neurons and has carnitine palmitoyltransferase activity
title_full CPT 1C is localized in endoplasmic reticulum of neurons and has carnitine palmitoyltransferase activity
title_fullStr CPT 1C is localized in endoplasmic reticulum of neurons and has carnitine palmitoyltransferase activity
title_full_unstemmed CPT 1C is localized in endoplasmic reticulum of neurons and has carnitine palmitoyltransferase activity
title_sort CPT 1C is localized in endoplasmic reticulum of neurons and has carnitine palmitoyltransferase activity
dc.creator.none.fl_str_mv Sierra, Adriana Y.
Gratacós, Esther
Carrasco, Patricia
Clotet, Josep
Ureña, Jesús
Serra i Cucurull, Dolors
Asins Muñoz, Guillermina
Hegardt, Fausto
Casals i Farré, Núria
author Sierra, Adriana Y.
author_facet Sierra, Adriana Y.
Gratacós, Esther
Carrasco, Patricia
Clotet, Josep
Ureña, Jesús
Serra i Cucurull, Dolors
Asins Muñoz, Guillermina
Hegardt, Fausto
Casals i Farré, Núria
author_role author
author2 Gratacós, Esther
Carrasco, Patricia
Clotet, Josep
Ureña, Jesús
Serra i Cucurull, Dolors
Asins Muñoz, Guillermina
Hegardt, Fausto
Casals i Farré, Núria
author2_role author
author
author
author
author
author
author
author
dc.subject.none.fl_str_mv Catàlisi
Carnitina palmitoïl-transferasa 1
Animals
Àcids grassos
Catalysis
Carnitine palmitoyltransferase I
Animals
Fatty acids
topic Catàlisi
Carnitina palmitoïl-transferasa 1
Animals
Àcids grassos
Catalysis
Carnitine palmitoyltransferase I
Animals
Fatty acids
description CPT1c is a carnitine palmitoyltransferase 1 (CPT1) isoform that is expressed only in the brain. The enzyme has recently been localized in neuron mitochondria. Although it has high sequence identity with the other two CPT1 isoenzymes (a and b), no CPT activity has been detected to date. Our results indicate that CPT1c is expressed in neurons but not in astrocytes of mouse brain sections. Overexpression of CPT1c fused to the green fluorescent protein in cultured cells demonstrates that CPT1c is localized in the endoplasmic reticulum rather than mitochondria and that the N-terminal region of CPT1c is responsible for endoplasmic reticulum protein localization. Western blot experiments with cell fractions from adult mouse brain corroborate these results. In addition, overexpression studies demonstrate that CPT1c does not participate in mitochondrial fatty acid oxidation, as would be expected from its subcellular localization. To identify the substrate of CPT1c enzyme, rat cDNA was overexpressed in neuronal PC-12 cells, and the levels of acylcarnitines were measured by high-performance liquid chromatography-mass spectrometry. Palmitoylcarnitine was the only acylcarnitine to increase in transfected cells, which indicates that palmitoyl-CoA is the enzyme substrate and that CPT1c has CPT1 activity. Microsomal fractions of PC-12 and HEK293T cells overexpressing CPT1c protein showed a significant increase in CPT1 activity of 0.57 and 0.13 nmol.mg(-1).min(-1), respectively, which is approximately 50% higher than endogenous CPT1 activity. Kinetic studies demonstrate that CPT1c has similar affinity to CPT1a for both substrates but 20-300 times lower catalytic efficiency.
publishDate 2008
dc.date.none.fl_str_mv 2008
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv https://hdl.handle.net/2445/223479
url https://hdl.handle.net/2445/223479
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv Reproducció del document publicat a: https://doi.org/10.1074/jbc.M707965200
Journal of Biological Chemistry, 2008, vol. 283, num.11, p. 6878-6885
https://doi.org/10.1074/jbc.M707965200
dc.rights.none.fl_str_mv cc by (c) Sierra, Adriana Y. et al., 2008
info:eu-repo/semantics/openAccess
rights_invalid_str_mv cc by (c) Sierra, Adriana Y. et al., 2008
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv American Society for Biochemistry and Molecular Biology
publisher.none.fl_str_mv American Society for Biochemistry and Molecular Biology
dc.source.none.fl_str_mv Articles publicats en revistes (Infermeria Fonamental i Clínica)
reponame:Dipòsit Digital de la UB
instname:Universidad de Barcelona
instname_str Universidad de Barcelona
reponame_str Dipòsit Digital de la UB
collection Dipòsit Digital de la UB
repository.name.fl_str_mv
repository.mail.fl_str_mv
_version_ 1869422975101435904
score 15,811543

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