Background: The carnitine/acylcarnitine carrier (CAC or CACT) mediates transport of acylcarnitines into mitochondria for the β-oxidation. CAC possesses Cys residues which respond to redox changes undergoing to SH/disulfide interconversion.
Methods: The effect of H2S has been investigated on the [(3)H]carnitine/carnitine antiport catalyzed by recombinant or native CAC reconstituted in proteoliposomes. Site-directed mutagenesis was employed for identifying Cys reacting with H2S.
Results: H2S led to transport inhibition, which was dependent on concentration, pH and time of incubation. Best inhibition with IC50 of 0.70 μM was observed at physiological pH after 30-60 min incubation. At longer times of incubation, inhibition was reversed. After oxidation of the carrier by O2, transport activity was rescued by H2S indicating that the inhibition/activation depends on the initial redox state of the protein. The observed effects were more efficient on the native rat liver transporter than on the recombinant protein. Only the protein containing both C136 and C155 responded to the reagent as the WT. While reduced responses were observed in the mutants containing C136 or C155. Multi-alignment of known mitochondrial carriers, highlighted that only the CAC possesses both Cys residues. This correlates well with the absence of effects of H2S on carriers which does not contain the Cys couple.
Conclusions: Altogether, these data demonstrate that H2S regulates the CAC by inhibiting or activating transport on the basis of the redox state of the protein.
General Significance: CAC represents a specific target of H2S among mitochondrial carriers in agreement with the presence of a reactive Cys couple.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/j.bbagen.2015.10.005 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Inhibition of the Mitochondrial Carnitine/Acylcarnitine Carrier by Itaconate through Irreversible Binding to Cysteine 136: Possible Pathophysiological Implications.
Biomolecules
June 2023
National Research Council (CNR), Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), Via Amendola 122/O, 70126 Bari, Italy.
Background: The carnitine/acylcarnitine carrier (CAC) represents the route of delivering acyl moieties to the mitochondrial matrix for accomplishing the fatty acid β-oxidation. The CAC has a couple of Cys residues (C136 and C155) most reactive toward ROS and redox signaling compounds such as GSH, NO, and HS. Among physiological compounds reacting with Cys, itaconate is produced during inflammation and represents the connection between oxidative metabolism and immune responses.
View Article and Find Full Text PDFThe mitochondrial carnitine/acylcarnitine carrier is regulated by hydrogen sulfide via interaction with C136 and C155.
Biochim Biophys Acta
January 2016
Department DiBEST (Biologia, Ecologia, Scienze della Terra), Unit of Biochemistry and Molecular Biotechnology, Via Bucci 4C, University of Calabria, 87036 Arcavacata di Rende, Italy; CNR Institute of Biomembranes and Bioenergetics, Via Amendola 165/A, 70126 Bari, Italy. Electronic address:
Background: The carnitine/acylcarnitine carrier (CAC or CACT) mediates transport of acylcarnitines into mitochondria for the β-oxidation. CAC possesses Cys residues which respond to redox changes undergoing to SH/disulfide interconversion.
Methods: The effect of H2S has been investigated on the [(3)H]carnitine/carnitine antiport catalyzed by recombinant or native CAC reconstituted in proteoliposomes.
Mitochondrial carnitine/acylcarnitine transporter, a novel target of mercury toxicity.
Chem Res Toxicol
May 2015
†CNR Institute of Biomembranes and Bioenergetics, via Amendola 165/A, 70126 Bari, Italy.
The effect of Hg(2+) and CH3Hg(+) on the mitochondrial carnitine/acylcarnitine transporter (CACT) has been studied on the recombinant protein and on the CACT extracted from HeLa cells or Zebrafish and reconstituted in proteoliposomes. Transport was abolished upon treatment of the recombinant CACT in proteoliposomes by Hg(2+) or CH3Hg(+). Inhibition was reversed by the SH reducing agent 1,4-dithioerythritol, GSH, and N-acetylcysteine.
View Article and Find Full Text PDFGlutathione controls the redox state of the mitochondrial carnitine/acylcarnitine carrier Cys residues by glutathionylation.
Biochim Biophys Acta
November 2013
CNR Institute of Biomembranes and Bioenergetics, via Amendola 165/A, 70126 Bari, Italy.
Background: The mitochondrial carnitine/acylcarnitine carrier (CAC) is essential for cell metabolism since it catalyzes the transport of acylcarnitines into mitochondria allowing the β-oxidation of fatty acids. CAC functional and structural properties have been characterized. Cys residues which could form disulfides suggest the involvement of CAC in redox switches.
View Article and Find Full Text PDFInhibition of mitochondrial carnitine/acylcarnitine transporter by H(2)O(2): molecular mechanism and possible implication in pathophysiology.
Chem Biol Interact
April 2013
CNR Institute of Biomembranes and Bioenergetics, via Amendola 165/A, 70126 Bari, Italy.
H(2)O(2) inhibits the [(3)H]carnitine/carnitine antiport catalysed by the mitochondrial carnitine/acylcarnitine transporter reconstituted in proteoliposomes. The inhibition was reversed by dithioerythritol, N-acetylcysteine and L-cysteine. Inhibition time-dependence revealed a faster and a slower reaction stages with orders of reaction of 1.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!