Cumero 2012 Br J Pharmacol
|Cumero S, Fogolari F, Domenis R, Zucchi R, Mavelli I, Contessi S (2012) F0F1-ATPsynthase as a molecular target of 3-Iodothyronamine. Br J Pharmacol 166:2331-47|
Abstract: Background & Purpose: T1AM is a thyronamine derivative of thyroid hormone acting as a signalling molecule via non-genomic effectors and can reach intracellular targets. In light of the importance of F0F1-ATPsynthase as a target in drug development, T1AM interaction with the enzyme is demonstrated by its effects on the activity and a model of binding locations is depicted.
Experimental Approach: Kinetic analyses were performed on F0F1-ATPsynthase in sub-mitochondrial particles and soluble F1-ATPase. Activity assays and immunodetection of the inhibitor protein IF1 were used and combined with molecular docking analyses. In situ respirometric analysis of T1AM effect was investigated on H9c2 cardiomyocytes.
Key Results: T1AM is a non-competitive inhibitor of F0F1-ATPsynthase whose binding is mutually exclusive with that of the inhibitors IF1 and aurovertin B. Distinct T1AM binding sites are consistent with results from both kinetic and docking analyses: at low nanomolar concentrations, T1AM binds to a high affinity-region likely located within the IF1 binding site, causing IF1 release; at higher concentrations, T1AM binds to a low affinity-region likely located within the aurovertin binding cavity and inhibits enzyme activity. Low nanomolar concentrations of T1AM elicit in cardiomyocytes an increase in ADP-stimulated mitochondrial respiration indicative for an activation of F0F1-ATPsynthase consistent with displacement of endogenous IF1, thereby reinforcing the in vitro results.
Conclusions & Implications: The T1AM effects upon F0F1-ATPsynthase are twofold: IF1 displacement and enzyme inhibition. By targeting F0F1-ATPsynthase within mitochondria T1AM might affect cell bioenergetics with a positive effect on mitochondrial energy production at low endogenous concentration. T1AM putative binding locations overlapping with IF1 and aurovertin binding sites are depicted. • Keywords: H9c2 cardiomyocytes, Inhibitor of ATPsynthase, Mitochondrial energy production, 3-iodothyronamine (T1AM), F0F1-ATPsynthase, F1-ATPase, IF1, Aurovertin B, Resveratrol, Multiple inhibition kinetics, Molecular docking analysis
• O2k-Network Lab: IT Udine Mavelli I
Labels: MiParea: Respiration, Pharmacology;toxicology
Enzyme: Complex V;ATP synthase Regulation: ATP, Inhibitor Coupling state: OXPHOS, ET