A5047494090- Phosphodiesterase function and regulation
- Receptor Mechanisms and Signaling
- Ion channel regulation and function
- Neuroscience and Neuropharmacology Research
- Mosquito-borne diseases and control
- Lipid Membrane Structure and Behavior
- Cholinesterase and Neurodegenerative Diseases
- Cardiac electrophysiology and arrhythmias
- Sphingolipid Metabolism and Signaling
- HIV Research and Treatment
- Virology and Viral Diseases
- Calcium signaling and nucleotide metabolism
- Cellular transport and secretion
- bioluminescence and chemiluminescence research
- Muscle Physiology and Disorders
- Cardiac Fibrosis and Remodeling
- RNA and protein synthesis mechanisms
- Adenosine and Purinergic Signaling
- Protein Kinase Regulation and GTPase Signaling
- Metabolism and Genetic Disorders
- Signaling Pathways in Disease
- Viral Infections and Outbreaks Research
- Listeria monocytogenes in Food Safety
- Histone Deacetylase Inhibitors Research
- Mitochondrial Function and Pathology
University of Oxford
2012-2025
University of Glasgow
2013
Justus-Liebig-Universität Gießen
1998-2009
Institute of Pharmacology
1998-2006
Compartmentalized cAMP/PKA signalling is now recognized as important for physiology and pathophysiology, yet a detailed understanding of the properties, regulation function local signals lacking. Here we present fluorescence resonance energy transfer (FRET)-based sensor, CUTie, which detects compartmentalized cAMP with unprecedented accuracy. targeted to specific multiprotein complexes at discrete plasmalemmal, sarcoplasmic reticular myofilament sites, reveals differential kinetics...
cAMP is a ubiquitous second messenger responsible for the cellular effects of multiple hormones and neurotransmitters via activation its main effector, protein kinase A (PKA). Multiple studies have shown that basal concentration in several cell types about 1 μM. This value well above reported required to half-maximally activate PKA, which measures 100-300 nM range. Several hypotheses been suggested explain this apparent discrepancy including inaccurate measurements intracellular free cAMP,...
Previous work has shown that the protein kinase A (PKA)–regulated phosphodiesterase (PDE) 4D3 binds to kinase–anchoring proteins (AKAPs). One such protein, AKAP9, localizes centrosome. In this paper, we investigate whether a PKA–PDE4D3–AKAP9 complex can generate spatial compartmentalization of cyclic adenosine monophosphate (cAMP) signaling at Real-time imaging fluorescence resonance energy transfer reporters shows centrosomal PDE4D3 modulated dynamic microdomain within which cAMP...
Listeriolysin (LLO) is a major virulence factor of Listeria monocytogenes, Gram-positive bacterium that can cause life-threatening diseases. Various signalling events and cellular effects, including modulation gene expression, are triggered by LLO through unknown mechanisms. Here, we demonstrate applied extracellularly at sublytic concentrations causes long-lasting oscillations the intracellular Ca2+ level human embryonic kidney cells; resulting from pulsed influx extracellular pores formed...
Abstract The sarcomeric troponin-tropomyosin complex is a critical mediator of excitation-contraction coupling, stability and force generation. We previously reported that induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) from patients with dilated cardiomyopathy (DCM) mutation, troponin T (TnT)-R173W, display sarcomere protein misalignment impaired contractility. Yet it not known how TnT mutation causes dysfunction microdomains these events contribute to proteins in presence...
Signaling by cAMP is organized in multiple distinct subcellular nanodomains regulated cAMP-hydrolyzing PDEs (phosphodiesterases). Cardiac β-adrenergic signaling has served as the prototypical system to elucidate compartmentalization. Although studies cardiac myocytes have provided an understanding of location and properties a handful compartments, overall view cellular landscape missing.
Abstract Propiogenic substrates and gut bacteria produce propionate, a post-translational protein modifier. In this study, we used mouse model of propionic acidaemia (PA) to study how disturbances propionate metabolism result in histone modifications changes gene expression that affect cardiac function. Plasma surrogates were raised PA mice, but female hearts manifested more profound acyl-CoAs, propionylation acetylation, transcription. These resulted moderate diastolic dysfunction with Ca...
Escherichia coli alpha-hemolysin (HlyA), archetype of a bacterial pore-forming toxin, has been reported to deregulate physiological Ca2+ channels, thus inducing periodic low-frequency oscillations that trigger transcriptional processes in mammalian cells. The present study was undertaken delineate the mechanisms underlying oscillations. Patch-clamp experiments were combined with single cell measurements intracellular and flowcytometric analyses. Application HlyA at subcytocidal...
Norepinephrine, a neuromodulator that activates β-adrenergic receptors (βARs), facilitates learning and memory as well the induction of synaptic plasticity in hippocampus. Several forms long-term potentiation (LTP) at Schaffer collateral CA1 synapse require stimulation both βARs N-methyl-D-aspartate (NMDARs). To understand mechanisms mediating interactions between βAR NMDAR signaling pathways, we combined FRET imaging cAMP hippocampal neuron cultures with spatial mechanistic modeling...
Abstract Programmed degradation of mitochondria by mitophagy, an essential process to maintain mitochondrial homeostasis, is not completely understood. Here we uncover a regulatory that controls mitophagy and involves the cAMP-degrading enzyme phosphodiesterase 2A2 (PDE2A2). We find PDE2A2 part signalosome at inner membrane where it interacts with contact site organizing system (MICOS). As this compartmentalised signalling regulates PKA-mediated phosphorylation MICOS component MIC60,...
Alphaviruses are small enveloped viruses that have been used extensively as model viruses. During infection, virus particles taken up into endosomes, where a low pH activates the viral fusion protein, E1. Fusion of and endosomal membranes releases core cytoplasm cores disassembled by interaction with 60S ribosomal subunits. Recently, we shown in vitro this disassembly is strongly stimulated pH. We proposed after entry cytoplasm, membrane proteins transferred to form an ion-permeable pore...
In the heart compartmentalisation of cAMP/protein kinase A (PKA) signalling is necessary to achieve a specific functional outcome in response different hormonal stimuli. Chronic exposure catecholamines known be detrimental and disrupted cAMP has been associated disease. However, most cases it remains unclear whether altered local an adaptive response, consequence disease or contributes pathogenetic process. We have previously demonstrated that isoforms PKA expressed cardiac myocytes, PKA-I...
Recently, we presented evidence that the E1 fusion protein of alphavirus Semliki Forest virus forms ion-permeable pores in target membrane after fusion. We proposed homologous proteins flaviviruses and hepatitis C form similar pores. To test this hypothesis for E flaviviruses, release [(3)H]choline from liposomes by flavivirus West Nile (WN) was determined. [(3)H]Choline released at mildly acid pH. The pH threshold depended on lipid composition. Release certain activated even neutral...
Recent studies have demonstrated that the actin binding protein, ezrin, and cAMP-sensor, EPAC1, cooperate to induce cell spreading in response elevations intracellular cAMP. To investigate mechanisms underlying these effects we generated a model of EPAC1-dependent based on stable transfection EPAC1 into HEK293T (HEK293T–EPAC1) cells. We found direct activation with EPAC-selective analogue, 8-pCPT-2′-O-Me-cAMP (007), promoted In addition, co-activation PKA, combination adenylate cyclase...
Recently, class II fusion proteins have been identified on the surface of alpha- and flaviviruses. These two functions besides membrane fusion: they generate an isometric lattice viral form ion-permeable pores at low pH. An attempt was made to identify inhibitors for ion generated by alphaviruses Semliki Forest virus Sindbis virus. can be detected analysed in three situations: (i) target during entry, performing patch-clamp measurements currents; (ii) particle, studying entry propidium...
Alpha- and flaviviruses contain class II fusion proteins, which form ion-permeable pores in the target membrane during virus entry. The generated entry of alphavirus Semliki Forest have been shown previously to be blocked by lanthanide ions. Here, analyses influence rare earth ions on West Nile Uganda S revealed an unexpected effect results showed that a 30 s treatment cells with appropriate ion changed cellular chemistry into state no longer supported multiplication flaviviruses. This...