Cortassa 2019 Front Physiol

From Bioblast
Revision as of 05:42, 26 October 2023 by Gnaiger Erich (talk | contribs)
(diff) ← Older revision | Latest revision (diff) | Newer revision β†’ (diff)
Publications in the MiPMap
Cortassa S, Aon MA, Sollott SJ (2019) Control and regulation of substrate selection in cytoplasmic and mitochondrial catabolic networks. A systems biology analysis. Front Physiol 10:201.

Β» PMID: 30906265 Open Access

Cortassa S, Aon MA, Sollott SJ (2019) Front Physiol

Abstract: Appropriate substrate selection between fats and glucose is associated with the success of interventions that maintain health such as exercise or caloric restriction, or with the severity of diseases such as diabetes or other metabolic disorders. Although the interaction and mutual inhibition between glucose and fatty-acids (FAs) catabolism has been studied for decades, a quantitative and integrated understanding of the control and regulation of substrate selection through central catabolic pathways is lacking. We addressed this gap here using a computational model representing cardiomyocyte catabolism encompassing glucose (Glc) utilization, pyruvate transport into mitochondria and oxidation in the tricarboxylic acid (TCA) cycle, Ξ²-oxidation of palmitate (Palm), oxidative phosphorylation, ion transport, pH regulation, and ROS generation and scavenging in cytoplasmic and mitochondrial compartments. The model is described by 82 differential equations and 119 enzymatic, electron transport and substrate transport reactions accounting for regulatory mechanisms and key players, namely pyruvate dehydrogenase (PDH) and its modulation by multiple effectors. We applied metabolic control analysis to the network operating with various Glc to Palm ratios. The flux and metabolites' concentration control were visualized through heat maps providing major insights into main control and regulatory nodes throughout the catabolic network. Metabolic pathways located in different compartments were found to reciprocally control each other. For example, glucose uptake and the ATP demand exert control on most processes in catabolism while TCA cycle activities and membrane-associated energy transduction reactions exerted control on mitochondrial processes namely Ξ²-oxidation. PFK and PDH, two highly regulated enzymes, exhibit opposite behavior from a control perspective. While PFK activity was a main rate-controlling step affecting the whole network, PDH played the role of a major regulator showing high sensitivity (elasticity) to substrate availability and key activators/inhibitors, a trait expected from a flexible substrate selector strategically located in the metabolic network. PDH regulated the rate of Glc and Palm consumption, consistent with its high sensitivity toward AcCoA, CoA, and NADH. Overall, these results indicate that the control of catabolism is highly distributed across the metabolic network suggesting that fuel selection between FAs and Glc goes well beyond the mechanisms traditionally postulated to explain the glucose-fatty-acid cycle.

β€’ Bioblast editor: Gnaiger E

Cortassa 2019 Front Physiol CORRECTION.png

Correction: ETF and CII ambiguity

ETF linked to beta-Oxidation is shown as a substrate of CII, which is wrong. For clarification, see Gnaiger (2023).

Correction: FADH2 and Complex II

Ambiguity alert.png
FADH2 is shown as the substrate feeding electrons into Complex II (CII). This is wrong and requires correction - for details see Gnaiger (2024).
Gnaiger E (2024) Complex II ambiguities ― FADH2 in the electron transfer system. J Biol Chem 300:105470. - Β»Bioblast linkΒ«


Enzyme: Complex II;succinate dehydrogenase 


Cookies help us deliver our services. By using our services, you agree to our use of cookies.