Evolution and functional divergence of the anoctamin family of membrane proteins

Our study suggests that anoctamins have evolved by series of duplication events, and that they are constrained by purifying selection. In addition we identified a number of protein domains, and amino acid residues which contribute to predicted functional divergence. Hopefully, this work will facilitate future functional characterization of the anoctamin membrane protein family

Neddylation regulates excitatory synaptic transmission and plasticity

Post-translational modifications, like phosphorylation, ubiquitylation, and sumoylation, have been shown to impact on synaptic neurotransmission by modifying pre- and postsynaptic proteins and therefore alter protein stability, localization, or protein-protein interactions. Previous studies showed that post-translational modifications are essential during the induction of synaptic plasticity, defined by a major reorganization of synaptic proteins. We demonstrated before that neddylation, a post-translational modification that covalently binds Nedd8 to lysine-residues, strongly affects neuronal maturation and spine stability. We now analysed the consequences of inhibiting neddylation on excitatory synaptic transmission and plasticity, which will help to narrow down possible targets, to make educated guesses, and test specific candidates. Here, we show that acute inhibition of neddylation impacts on synaptic neurotransmission before morphological changes occur. Our data indicate that pre- and postsynaptic proteins are neddylated since the inhibition of neddylation impacts on presynaptic release probability and postsynaptic receptor stabilization. In addition, blocking neddylation during the induction of long-term potentiation and long-term inhibition abolished both forms of synaptic plasticity. Therefore, this study shows the importance of identifying synaptic targets of the neddylation pathway to understand the regulation of synaptic transmission and plasticity.Fil: Brockmann, Marisa M.. Universitat Bonn; Alemania. Max Planck Institute Of Psychiatry; AlemaniaFil: Döngi, Michael. Universitat Bonn; AlemaniaFil: Einsfelder, Ulf. Universitat Bonn; AlemaniaFil: Körber, Nils. Universitat Bonn; AlemaniaFil: Refojo, Damian. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación en Biomedicina de Buenos Aires - Instituto Partner de la Sociedad Max Planck; ArgentinaFil: Stein, Valentin. Universitat Bonn; Alemani

Autaptic cultures of human induced neurons as a versatile platform for studying synaptic function and neuronal morphology

Recently developed technology to differentiate induced pluripotent stem cells (iPSCs) into human induced neurons (iNs) provides an exciting opportunity to study the function of human neurons. However, functional characterisations of iNs have been hampered by the reliance on mass culturing protocols which do not allow assessment of synaptic release characteristics and neuronal morphology at the individual cell level with quantitative precision. Here, we have developed for the first time a protocol to generate autaptic cultures of iPSC-derived iNs. We show that our method efficiently generates mature, autaptic iNs with robust spontaneous and action potential-driven synaptic transmission. The synaptic responses are sensitive to modulation by metabotropic receptor agonists as well as potentiation by acute phorbol ester application. Finally, we demonstrate loss of evoked and spontaneous release by Unc13A knockdown. This culture system provides a versatile platform allowing for quantitative and integrative assessment of morphophysiological and molecular parameters underlying human synaptic transmission

Asynchronous release sites align with NMDA receptors in mouse hippocampal synapses

© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Li, S., Raychaudhuri, S., Lee, S. A., Brockmann, M. M., Wang, J., Kusick, G., Prater, C., Syed, S., Falahati, H., Ramos, R., Bartol, T. M., Hosy, E., & Watanabe, S. Asynchronous release sites align with NMDA receptors in mouse hippocampal synapses. Nature Communications, 12(1), (2021): 677, https://doi.org/10.1038/s41467-021-21004-x.Neurotransmitter is released synchronously and asynchronously following an action potential. Our recent study indicates that the release sites of these two phases are segregated within an active zone, with asynchronous release sites enriched near the center in mouse hippocampal synapses. Here we demonstrate that synchronous and asynchronous release sites are aligned with AMPA receptor and NMDA receptor clusters, respectively. Computational simulations indicate that this spatial and temporal arrangement of release can lead to maximal membrane depolarization through AMPA receptors, alleviating the pore-blocking magnesium leading to greater activation of NMDA receptors. Together, these results suggest that release sites are likely organized to activate NMDA receptors efficiently.e also thank the Marine Biological Laboratory and their Neurobiology course for supporting the initial set of experiments (course supported by National Institutes of Health grant R25NS063307). S.W. and this work were supported by start-up funds from the Johns Hopkins University School of Medicine, Johns Hopkins Discovery funds, and the National Science Foundation (1727260), the National Institutes of Health (1DP2 NS111133-01 and 1R01 NS105810-01A1) awarded to S.W. S.W. is an Alfred P. Sloan fellow, McKnight Foundation Scholar, and Klingenstein and Simons Foundation scholar. G.K. was supported by a grant from the National Institutes of Health to the Biochemistry, Cellular and Molecular Biology Program of the Johns Hopkins University School of Medicine (T32 GM007445) and is a National Science Foundation Graduate Research Fellow (2016217537). E.H. and T.M.B. are supported by CRCNS-NIH-ANR grant AMPAR-T. The EM ICE high-pressure freezer was purchased partly with funds from an equipment grant from the National Institutes of Health (S10RR026445) awarded to Scot C Kuo

Past, present, and future of sleep medicine research in Latin America.

Sleep medicine is a relatively young field with exponential growth in development and research in the last decades. Parallel to the advances in the United States, Latin America also had its beginnings in sleep medicine housed in neuroscience laboratories. Since the very first Latin American meeting in 1985, and the first sleep society in 1993, sleep research has undergone significant development in subsequent years. From contributions in animal research that allowed understanding of the activity of the brain during sleep to the studies that improved our knowledge of sleep disorders in humans, Latin America has become a scientific hub for expansion of sleep research. In this article, we present a historical account of the development of sleep medicine in Latin America, the current state of education and the achievements in research throughout history, and the latest advances in the trending areas of sleep science and medicine. These findings were presented during World Sleep Society meeting in Vancouver in 2019 and complement the work on sleep societies and training published by Vizcarra-Escobar et al in their article Sleep societies and sleep training programs in Latin America (J Clin Sleep Med. 2020;16(6):983-988)

Parkin contributes to synaptic vesicle autophagy in Bassoon-deficient mice

Mechanisms regulating the turnover of synaptic vesicle (SV) proteins are not well understood. They are thought to require poly-ubiquitination and degradation through proteasome, endo-lysosomal or autophagy-related pathways. Bassoon was shown to negatively regulate presynaptic autophagy in part by scaffolding Atg5. Here, we show that increased autophagy in Bassoon knockout neurons depends on poly-ubiquitination and that the loss of Bassoon leads to elevated levels of ubiquitinated synaptic proteins per se. Our data show that Bassoon knockout neurons have a smaller SV pool size and a higher turnover rate as indicated by a younger pool of SV2. The E3 ligase Parkin is required for increased autophagy in Bassoon-deficient neurons as the knockdown of Parkin normalized autophagy and SV protein levels and rescued impaired SV recycling. These data indicate that Bassoon is a key regulator of SV proteostasis and that Parkin is a key E3 ligase in the autophagy-mediated clearance of SV proteins

RIM-binding protein 2 regulates release probability by fine-tuning calcium channel localization at murine hippocampal synapses

The tight spatial coupling of synaptic vesicles and voltage-gated Ca2+ channels (CaVs) ensures efficient action potential-triggered neurotransmitter release from presynaptic active zones (AZs). Rab-interacting molecule-binding proteins (RIM-BPs) interact with Ca2+ channels and via RIM with other components of the release machinery. Although human RIM-BPs have been implicated in autism spectrum disorders, little is known about the role of mammalian RIM-BPs in synaptic transmission. We investigated RIM-BP2-deficient murine hippocampal neurons in cultures and slices. Short-term facilitation is significantly enhanced in both model systems. Detailed analysis in culture revealed a reduction in initial release probability, which presumably underlies the increased short-term facilitation. Superresolution microscopy revealed an impairment in CaV2.1 clustering at AZs, which likely alters Ca2+ nanodomains at release sites and thereby affects release probability. Additional deletion of RIM-BP1 does not exacerbate the phenotype, indicating that RIM-BP2 is the dominating RIM-BP isoform at these synapses

Interleukin-13 and its receptor are synaptic proteins involved in plasticity and neuroprotection

Il-13 is expressed in neurons and IL-13 ko causes memory impairment. Here, authors show that IL-13 and its receptor IL-13Ra1 are pre- and post-synaptic proteins, respectively, involved in synaptic signaling, plasticity and neuroprotection