Related Experiment Video For ROS
Updated: Jul 25, 2025
Inner Mitochondrial Membrane Sensitivity to Na+ Reveals Partially Segmented Functional CoQ Pools
Published on: July 20, 2022
Inhibition of the Mitochondrial Carnitine/Acylcarnitine Carrier by Itaconate through Irreversible Binding to Cysteine
Nicola Giangregorio1, Annamaria Tonazzi1, Lara Console2
1National 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 H2S. Among physiological compounds reacting with Cys, itaconate is produced during inflammation and represents the connection between oxidative metabolism and immune responses. The possible interaction between the CAC and itaconate has been investigated.
Methods:
the modulatory effects of itaconate on the transport activity of the native and recombinant CAC were tested using the proteoliposome experimental model together with site-directed mutagenesis and computational analysis.
Results:
Itaconate reacts with the CAC causing irreversible inhibition. Dose-response experiment performed with the native and recombinant protein showed IC50 for itaconate of 11 ± 4.6 mM and 8.4 ± 2.9 mM, respectively. The IC50 decreased to 3.8 ± 1.0 mM by lowering the pH from pH 7.0 to pH 6.5. Inhibition kinetics revealed a non-competitive type of inhibition. C136 is the main target of itaconate, as demonstrated by the increased IC50 of mutants in which this Cys was substituted by Val. The central role of C136 was confirmed by covalent docking. Administration of dimethyl itaconate to HeLa cells inhibited the CAC transport activity, suggesting that itaconate could react with the CAC also in intact cells.
Related Concept Videos
01:30The Electron Transport Chain
Inhibitors of the electron transport chain
Rotenone, a widely used pesticide, prevents electron transfer from Fe-S cluster to ubiquinone or Q...
01:46Electron Transport Chain: Complex I and II
ROS generation is regulated and maintained at moderate levels necessary...
01:19Allosteric Proteins-ATCase
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis...
01:15Pyruvate Oxidation
First, the enzyme pyruvate dehydrogenase removes the carboxyl group from pyruvate and releases it as carbon dioxide. The stripped molecule is then oxidized and releases electrons, which are then picked up by NAD+...
00:46Feedback Inhibition
01:19Translocation of Proteins into the Mitochondria
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...