Structural basis of ketamine actions upon man NMDA receptors

In 2010, the pan-assay interference compounds (PAINS) rule was proposed to identify false-positive compounds, especially frequent hitters (FHs), in biological screening campaigns, and has rapidly become an essential component in drug design. However, the specific mechanisms remain unknown, and the result validation and follow-up processing schemes are still unclear. In this review, a large benchmark collection of >600,000 compounds sourced from databases and the literature, including six common false-positive mechanisms, was used to evaluate the detection ability of PAINS. In addition, 400 million purchasable molecules from the ZINC database were also applied to PAINS screening. The results indicate that the PAINS rule is not suitable for the screening of all types of false-positive results and needs more improvement.Trace element selenium (Se) is incorporated as the 21st amino acid, selenocysteine (Sec), into selenoproteins through tRNA[Ser]Sec. Selenoproteins act as gatekeepers of redox homeostasis and modulate immune function to effect anti-inflammation and resolution. However, mechanistic underpinnings involving metabolic reprogramming during inflammation and resolution remain poorly understood. Bacterial endotoxin lipopolysaccharide (LPS) activation of murine bone marrow-derived macrophages (BMDMs) cultured in the presence or absence of Se (as selenite) was used to examine temporal changes in the proteome and metabolome by multiplexed tandem mass tag-quantitative proteomics, metabolomics, and machine-learning approaches. Kinetic deltagram and clustering analysis indicated addition of Se led to extensive reprogramming of cellular metabolism upon stimulation with LPS enhancing PPP, TCA cycle, and OXPHOS, to aid in the phenotypic transition towards alternatively activated macrophages, synonymous with resolution of inflammation. Remodeling of metabolic pathways and consequent metabolic adaptation towards pro-resolving phenotypes began with Se treatment at 0 h and became most prominent around 8 h post LPS stimulation that included succinate dehydrogenase complex (Sdh), pyruvate kinase (Pkm), and Sedoheptulokinase (Shpk). Se-dependent modulation of these pathways predisposed BMDMs to preferentially increase OXPHOS to efficiently regulate inflammation and its timely resolution. Use of macrophages lacking selenoproteins, indicated that all three metabolic nodes were sensitive to selenoproteome expression. Furthermore, inhibition of Sdh with dimethylmalonate affected the pro-resolving effects of Se by increasing the resolution interval in a murine peritonitis model. In summary, our studies provide novel insights into the role of cellular Se via metabolic reprograming to facilitate anti-inflammation and pro-resolution.Formation of myofibers, osteoclasts, syncytiotrophoblasts and fertilized zygotes share a common step, cell-cell fusion. Recent years have brought about considerable progress in identifying some of the proteins involved in these and other cell-fusion processes. However, even for the best characterized cell-fusions, we still do not know the mechanisms that regulate the timing of cell-fusion events. Are they fully controlled by the expression of fusogenic proteins or do they also depend on some triggering signal(s) that activates these proteins? The latter scenario would be analogous to the mechanisms that control the timing of exocytosis initiated by Ca2+ influx and virus-cell fusion initiated by low pH- or receptor-interaction. Diverse cell-fusions are accompanied by the non-apoptotic exposure of phosphatidylserine at the surface of fusing cells. Here we review data on the dependence of membrane remodeling in cell-fusion on phosphatidylserine and phosphatidylserine-recognizing proteins and discuss the hypothesis that cell surface phosphatidylserine serves as a conserved "fuse me" signal regulating the time and place of cell-fusion processes.Ariadne-1 (Ari-1) is an E3 ubiquitin-ligase essential for neuronal development, but whose neuronal substrates are yet to be identified. To search for putative Ari-1 substrates, we used an in vivo ubiquitin biotinylation strategy coupled to quantitative proteomics of Drosophila heads. We identified sixteen candidates that met the established criteria a significant change of at least two-fold increase on ubiquitination, with at least two unique peptides identified. Amongst those candidates, we identified Comatose (Comt), the homologue of the N-ethylmaleimide sensitive factor (NSF), which is involved in neurotransmitter release. Using a pulldown approach that relies on the overexpression and stringent isolation of a GFP-fused construct, we validate Comt/NSF to be an ubiquitination substrate of Ari-1 in fly neurons, resulting in the preferential monoubiquitination of Comt/NSF. We tested the possible functional relevance of this modification using Ari-1 loss of function mutants, which displayed a lower rate of spontaneous neurotransmitter release due to failures at the pre-synaptic side. Tocilizumab supplier By contrast, evoked release in Ari-1 mutants was enhanced compared to controls in a Ca2+ dependent manner without modifications in the number of active zones, indicating that the probability of release per synapse is increased in these mutants. This phenotype distinction between spontaneous versus evoked release suggests that NSF activity may discriminate between these two types of vesicle fusion. Our results thus provide a mechanism to regulate NSF activity in the synapse through Ari-1-dependent ubiquitination.The Ca-ATPase isoform 2a (SERCA2a) pumps cytosolic Ca2+ into the sarcoplasmic reticulum (SR) of cardiac myocytes, enabling muscle relaxation during diastole. Abnormally high cytosolic [Ca2+] is a central factor in heart failure, suggesting that augmentation of SERCA2a Ca2+ transport activity could be a promising therapeutic approach. SERCA2a is inhibited by the protein phospholamban (PLB), and a novel transmembrane peptide, dwarf open reading frame (DWORF), is proposed to enhance SR Ca2+ uptake and myocyte contractility by displacing PLB from binding to SERCA2a. However, establishing DWORF's precise physiological role requires further investigation. In the present study, we developed cell-based FRET biosensor systems that can report on protein-protein interactions and structural changes in SERCA2a complexes with PLB and/or DWORF. To test the hypothesis that DWORF competes with PLB to occupy the SERCA2a binding site, we transiently transfected DWORF into a stable HEK cell line expressing SERCA2a labeled with a FRET donor and PLB labeled with a FRET acceptor.