Allosteric inhibition of adenylyl cyclase type 5 by G-protein: a molecular dynamics study

Frezza, E.; Amans, T.-M.; Martin, J.

doi:10.1101/2020.06.23.166710

Home/Archive/bioRxiv

bioRxiv · 10.1101/2020.06.23.166710

Allosteric inhibition of adenylyl cyclase type 5 by G-protein: a molecular dynamics study

Frezza, E.·Amans, T.-M.·Martin, J.

View original source ↗Export metadata ↓

Abstract

Adenylyl cyclases (ACs) have a crucial role in many signal transduction pathways, in particular in the intricate control of cyclic AMP (cAMP) generation from adenosine triphosphate (ATP). Using homology models developed from existing structural data and docking experiments, we have carried out all-atom, microsecond-scale molecular dynamics simulations on the AC5 isoform of adenylyl cyclase bound to the inhibitory G-protein subunit Gi in the presence and in the absence of ATP. The results show that Gi have significant effects on the structure and flexibility of adenylyl cyclase, as observed earlier for the binding of ATP and Gs. New data on Gi bound to the C1 domain of AC5 help to explain how Gi inhibits enzyme activity and to get insight on its regulation. Simulations also suggest a crucial role of ATP in the regulation of stimulation and inhibition of AC5. Author summaryThe neurons that compose the human brain are able to respond to multiple inputs from other neurons. The chemical "integration" of these inputs then decides whether a given neuron passes on a signal or not. External chemical messages act on neurons via proteins in their membranes that trigger cascades of reactions within the cell. One key molecule in these signaling cascades is cyclic adenosine monophosphate (cAMP) that is chemically synthesized from adenosine triphosphate (ATP) by the enzyme adenylyl cyclase (AC). We are investigating the mechanisms that control how much cAMP is produced as a function of the signals received by the neuron. In particular, we have studied the inhibition effect of a key protein, termed Gi, on AC, and we compare it with the stimulator effect of another key protein termed Gs. Using microsecond molecular simulations, we have been able to show how binding Gi to AC changes its structure and its dynamics so that its enzymatic activity is quenched and that ATP seems to have a crucial role in the regulation of stimulation and inhibition of AC5.

Source connections

Published article ↗

Explore related subjects

molecular biology Preprint

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Frezza, E., Amans, T.-M., Martin, J.. 2020-06-23. Allosteric inhibition of adenylyl cyclase type 5 by G-protein: a molecular dynamics study. https://doi.org/10.1101/2020.06.23.166710

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Trans-branching of polyubiquitin chains orchestrates the DNA replication stress response

Polyubiquitin chain geometry dictates functional consequences of ubiquitylation. Although branched polyubiquitin chains are abundant in cells, little is known about their functions. Here we show that branching on the DNA replication factor PCNA, mediated by the ubiquitin-conjugating enzyme UBE2K and involving lysines 63 and 48 of ubiquitin, orchestrates the sequence of events in response to replication stress. By inducing VCP-dependent extraction of PCNA from chromatin, branching promotes re-priming of stalled forks and necessitates a BRCA1-dependent pathway of daughter-strand gap repair. Our study identifies hyper-accumulation of daughter-strand gaps as the mechanistic basis underlying the toxicity of inhibitors of the PCNA-specific isopeptidase, USP1, in BRCA1-deficient cells. Moreover, an unexpected preference of UBE2K to operate in trans suggests a general timing mechanism to organize hierarchies amongst ubiquitin signals.

molecular biology↗

bioRxiv2026

Impaired proteostasis is an early feature of the diabetic heart in humans and mice

Diabetes and obesity increase cardiac lipid levels leading to cardiomyopathy and heart failure. We hypothesized that intermittent fasting would reduce cardiac lipid levels. Surprisingly, intermittent fasting increased myocardial triglyceride content, but rescued mortality and attenuated cardiomyopathy in mice overexpressing cardiomyocyte acyl-CoA synthetase 1 (MHC-ACSL1). Lipid overload caused cardiomyocyte accumulation of polyubiquitinated protein aggregates containing desmin, a scaffolding intermediate filament protein, which intermittent fasting prevented. Furthermore, intermittent fasting reversed elevated myocardial C16:0 ceramide content, and knockdown of ceramide synthase CerS5 and CerS6 reduced palmitate-induced protein aggregation, highlighting a role for C16:0 ceramides in this pathology. Conversely, impairing aggrephagy with cardiomyocyte-specific p62 ablation induced heart failure in mice fed a high-fat diet, with paradoxically reduced cardiac lipid content. Crucially, non-failing diabetic human hearts also exhibited protein aggregate pathology. Taken together, these results demonstrate that impaired proteostasis characterizes cardiomyopathy from cardiac lipid overload and identify a promising new therapeutic target for this condition.

molecular biology↗

bioRxiv2026

Spatial profiling and neurovascular communication in the developing and adolescent cortex following prenatal alcohol exposure

Fetal alcohol spectrum disorders (FASD) constitute a wide range of developmental, cognitive, and behavioral impairments caused by prenatal alcohol exposure (PAE). Although neuronal and vascular consequences of PAE have been studied, how alcohol affects the cerebrovasculature within the framework of the neurovascular unit (NVU) across development remains poorly understood. At minimum, the NVU comprises neurons, astrocyte endfeet, and endothelial cells (ECs), which coordinate to maintain brain homeostasis. Here, we used the NanoString Digital Spatial Profiling platform to characterize spatial transcriptomic data from neurons, astrocytes, and ECs from PAE and saccharin (SAC) control cortices at embryonic day 18 (E18) and postnatal day 28 (P28). Differentially expressed genes were then used for Ingenuity Pathway Analysis (IPA) to identify altered biological pathways and perform comparison analyses across developmental time points, while CellChat was used to infer cell cell communication networks. We uncovered thousands of differentially expressed genes and numerous altered pathways and biological processes in PAE cortices across development. Both IPA and CellChat analyses implicated dysregulation of vascular and extracellular matrix (ECM) remodeling, cell adhesion, and neuroinflammatory signaling. CellChat further predicted the loss of several key bidirectional relationships and altered ligand-receptor interactions among neurovascular cell types at E18 and P28. Overall, these findings identify PAE associated alterations in neurovascular gene expression and intercellular signaling across development, providing potential mechanisms by which PAE may disrupt neurodevelopment.

molecular biology↗