Dataset Information

Mitochondrial sAC-cAMP-PKA Axis Modulates the ΔΨ_m-Dependent Control Coefficients of the Respiratory Chain Complexes: Evidence of Respirasome Plasticity.

ABSTRACT: The current view of the mitochondrial respiratory chain complexes I, III and IV foresees the occurrence of their assembly in supercomplexes, providing additional functional properties when compared with randomly colliding isolated complexes. According to the plasticity model, the two structural states of the respiratory chain may interconvert, influenced by the intracellular prevailing conditions. In previous studies, we suggested the mitochondrial membrane potential as a factor for controlling their dynamic balance. Here, we investigated if and how the cAMP/PKA-mediated signalling influences the aggregation state of the respiratory complexes. An analysis of the inhibitory titration profiles of the endogenous oxygen consumption rates in intact HepG2 cells with specific inhibitors of the respiratory complexes was performed to quantify, in the framework of the metabolic flux theory, the corresponding control coefficients. The attained results, pharmacologically inhibiting either PKA or sAC, indicated that the reversible phosphorylation of the respiratory chain complexes/supercomplexes influenced their assembly state in response to the membrane potential. This conclusion was supported by the scrutiny of the available structure of the CI/CIII₂/CIV respirasome, enabling us to map several PKA-targeted serine residues exposed to the matrix side of the complexes I, III and IV at the contact interfaces of the three complexes.

SUBMITTER: Scrima R

PROVIDER: S-EPMC10607245 | biostudies-literature | 2023 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Mitochondrial sAC-cAMP-PKA Axis Modulates the ΔΨ<sub>m</sub>-Dependent Control Coefficients of the Respiratory Chain Complexes: Evidence of Respirasome Plasticity.

Scrima Rosella R Cela Olga O Rosiello Michela M Nabi Ari Qadir AQ Piccoli Claudia C Capitanio Giuseppe G Tucci Francesco Antonio FA Leone Aldo A Quarato Giovanni G Capitanio Nazzareno N

International journal of molecular sciences 20231013 20

The current view of the mitochondrial respiratory chain complexes I, III and IV foresees the occurrence of their assembly in supercomplexes, providing additional functional properties when compared with randomly colliding isolated complexes. According to the plasticity model, the two structural states of the respiratory chain may interconvert, influenced by the intracellular prevailing conditions. In previous studies, we suggested the mitochondrial membrane potential as a factor for controlling ...[more]

PMID: 37894823

Similar Datasets

Project description:Cyclic 3'5' adenosine monophosphate (cAMP)-dependent-protein kinase (PKA) signaling is a fundamental regulatory pathway for mediating cellular responses to hormonal stimuli. The pathway is activated by high-affinity association of cAMP with the regulatory subunit of PKA and signal termination is achieved upon cAMP dissociation from PKA. Although steps in the activation phase are well understood, little is known on how signal termination/resetting occurs. Due to the high affinity of cAMP to PKA (KD ∼ low nM), bound cAMP does not readily dissociate from PKA, thus begging the question of how tightly bound cAMP is released from PKA to reset its signaling state to respond to subsequent stimuli. It has been recently shown that phosphodiesterases (PDEs) can catalyze dissociation of bound cAMP and thereby play an active role in cAMP signal desensitization/termination. This is achieved through direct interactions with the regulatory subunit of PKA, thereby facilitating cAMP dissociation and hydrolysis. In this study, we have mapped direct interactions between a specific cyclic nucleotide phosphodiesterase (PDE8A) and a PKA regulatory subunit (RIα isoform) in mammalian cAMP signaling, by a combination of amide hydrogen/deuterium exchange mass spectrometry, peptide array, and computational docking. The interaction interface of the PDE8A:RIα complex, probed by peptide array and hydrogen/deuterium exchange mass spectrometry, brings together regions spanning the phosphodiesterase active site and cAMP-binding sites of RIα. Computational docking combined with amide hydrogen/deuterium exchange mass spectrometry provided a model for parallel dissociation of bound cAMP from the two tandem cAMP-binding domains of RIα. Active site coupling suggests a role for substrate channeling in the PDE-dependent dissociation and hydrolysis of cAMP bound to PKA. This is the first instance, to our knowledge, of PDEs directly interacting with a cAMP-receptor protein in a mammalian system, and highlights an entirely new class of binding partners for RIα. This study also highlights applications of structural mass spectrometry combined with computational docking for mapping dynamics in transient signaling protein complexes. Together, these results present a novel and critical role for phosphodiesterases in moderating local concentrations of cAMP in microdomains and signal resetting.

Dataset Information

Mitochondrial sAC-cAMP-PKA Axis Modulates the ΔΨ_m-Dependent Control Coefficients of the Respiratory Chain Complexes: Evidence of Respirasome Plasticity.

Publications

Mitochondrial sAC-cAMP-PKA Axis Modulates the ΔΨ<sub>m</sub>-Dependent Control Coefficients of the Respiratory Chain Complexes: Evidence of Respirasome Plasticity.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Dataset Information

Mitochondrial sAC-cAMP-PKA Axis Modulates the ΔΨm-Dependent Control Coefficients of the Respiratory Chain Complexes: Evidence of Respirasome Plasticity.

Publications

Mitochondrial sAC-cAMP-PKA Axis Modulates the ΔΨ<sub>m</sub>-Dependent Control Coefficients of the Respiratory Chain Complexes: Evidence of Respirasome Plasticity.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Mitochondrial sAC-cAMP-PKA Axis Modulates the ΔΨ_m-Dependent Control Coefficients of the Respiratory Chain Complexes: Evidence of Respirasome Plasticity.