Endogenous neurosteroids and their synthetic analogues-neuroactive steroids-have been found to bind to muscarinic acetylcholine receptors and allosterically modulate acetylcholine binding and function. Using radioligand binding experiments we investigated their binding mode. We show that neuroactive steroids bind to two binding sites on muscarinic receptors. Their affinity for the high-affinity binding site is about 100 nM. Their affinity for the low-affinity binding site is about 10 µM. The high-affinity binding occurs at the same site as binding of steroid-based WIN-compounds that is different from the common allosteric binding site for alcuronium or gallamine that is located between the second and third extracellular loop of the receptor. This binding site is also different from the allosteric binding site for the structurally related aminosteroid-based myorelaxants pancuronium and rapacuronium. Membrane cholesterol competes with neurosteroids/neuroactive steroids binding to both high- and low-affinity binding site, indicating that both sites are oriented towards the cell membrane..
- MeSH
- alosterická regulace účinky léků fyziologie MeSH
- androstany metabolismus farmakologie MeSH
- androsteny metabolismus farmakologie MeSH
- benzimidazoly metabolismus farmakologie MeSH
- CHO buňky MeSH
- cholesterol metabolismus MeSH
- Cricetulus MeSH
- křečci praví MeSH
- lidé MeSH
- nedepolarizující myorelaxancia metabolismus farmakologie MeSH
- neurosteroidy metabolismus MeSH
- receptory muskarinové metabolismus MeSH
- triethojodid gallaminia metabolismus farmakologie MeSH
- vazebná místa účinky léků fyziologie MeSH
- vekuronium analogy a deriváty metabolismus farmakologie MeSH
- zvířata MeSH
- Check Tag
- křečci praví MeSH
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Allosteric modulators are ligands that bind to a site on the receptor that is spatially separated from the orthosteric binding site for the endogenous neurotransmitter. Allosteric modulators modulate the binding affinity, potency, and efficacy of orthosteric ligands. Muscarinic acetylcholine receptors are prototypical allosterically-modulated G-protein-coupled receptors. They are a potential therapeutic target for the treatment of psychiatric, neurologic, and internal diseases like schizophrenia, Alzheimer's disease, Huntington disease, type 2 diabetes, or chronic pulmonary obstruction. Here, we reviewed the progress made during the last decade in our understanding of their mechanisms of binding, allosteric modulation, and in vivo actions in order to understand the translational impact of studying this important class of pharmacological agents. We overviewed newly developed allosteric modulators of muscarinic receptors as well as new spin-off ideas like bitopic ligands combining allosteric and orthosteric moieties and photo-switchable ligands based on bitopic agents.
- MeSH
- agonisté muskarinových receptorů metabolismus MeSH
- alosterická regulace fyziologie MeSH
- antagonisté muskarinových receptorů metabolismus MeSH
- lidé MeSH
- ligandy MeSH
- receptory muskarinové metabolismus fyziologie MeSH
- receptory spřažené s G-proteiny MeSH
- vazebná místa MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Mycobacterium tuberculosis (Mtb) causes both acute tuberculosis and latent, symptom-free infection that affects roughly one-third of the world's population. It is a globally important pathogen that poses multiple dangers. Mtb reprograms its metabolism in response to the host niche, and this adaptation contributes to its pathogenicity. Knowledge of the metabolic regulation mechanisms in Mtb is still limited. Pyruvate kinase, involved in the late stage of glycolysis, helps link various metabolic routes together. Here, we demonstrate that Mtb pyruvate kinase (Mtb PYK) predominantly catalyzes the reaction leading to the production of pyruvate, but its activity is influenced by multiple metabolites from closely interlinked pathways that act as allosteric regulators (activators and inhibitors). We identified allosteric activators and inhibitors of Mtb PYK originating from glycolysis, citrate cycle, nucleotide/nucleoside inter-conversion related pathways that had not been described so far. Enzyme was found to be activated by fructose-1,6-bisphosphate, ribose-5-phosphate, adenine, adenosine, hypoxanthine, inosine, L-2-phosphoglycerate, l-aspartate, glycerol-2-phosphate, glycerol-3-phosphate. On the other hand thiamine pyrophosphate, glyceraldehyde-3-phosphate and L-malate were identified as inhibitors of Mtb PYK. The detailed kinetic analysis indicated a morpheein model of Mtb PYK allosteric control which is strictly dependent on Mg2+ and substantially increased by the co-presence of Mg2+ and K+.
Neutral trehalase 1 (Nth1) from Saccharomyces cerevisiae catalyzes disaccharide trehalose hydrolysis and helps yeast to survive adverse conditions, such as heat shock, starvation or oxidative stress. 14-3-3 proteins, master regulators of hundreds of partner proteins, participate in many key cellular processes. Nth1 is activated by phosphorylation followed by 14-3-3 protein (Bmh) binding. The activation mechanism is also potentiated by Ca(2+) binding within the EF-hand-like motif. This review summarizes the current knowledge about trehalases and the molecular and structural basis of Nth1 activation. The crystal structure of fully active Nth1 bound to 14-3-3 protein provided the first high-resolution view of a trehalase from a eukaryotic organism and showed 14-3-3 proteins as structural modulators and allosteric effectors of multi-domain binding partners.
