Assembly and maturation of synapses at the Drosophila neuromuscular junction (NMJ) depend on trans-synaptic neurexin/neuroligin signalling, which is promoted by the scaffolding protein Syd-1 binding to neurexin. Here we report that the scaffold protein spinophilin binds to the C-terminal portion of neurexin and is needed to limit neurexin/neuroligin signalling by acting antagonistic to Syd-1. Loss of presynaptic spinophilin results in the formation of excess, but atypically small active zones. Neuroligin-1/neurexin-1/Syd-1 levels are increased at spinophilin mutant NMJs, and removal of single copies of the neurexin-1, Syd-1 or neuroligin-1 genes suppresses the spinophilin-active zone phenotype. Evoked transmission is strongly reduced at spinophilin terminals, owing to a severely reduced release probability at individual active zones. We conclude that presynaptic spinophilin fine-tunes neurexin/neuroligin signalling to control active zone number and functionality, thereby optimizing them for action potential-induced exocytosis.
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http://dx.doi.org/10.1038/ncomms9362 | DOI Listing |
Neurochem Int
May 2024
Mesulam Center for Cognitive Neurology and Alzheimer's Disease, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA. Electronic address:
Cortical synaptic loss has emerged as an early abnormality in Alzheimer's disease (AD) with a strong relationship to cognitive performance. However, the status of synapses in frontotemporal lobar degeneration (FTLD) has received meager experimental attention. The purpose of this study was to investigate changes in cortical synaptic proteins in FTLD with tar DNA binding protein-43 (TDP-43) proteinopathy.
View Article and Find Full Text PDFElife
September 2023
Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany.
We still face fundamental gaps in understanding how molecular plastic changes of synapses intersect with circuit operation to define behavioral states. Here, we show that an antagonism between two conserved regulatory proteins, Spinophilin (Spn) and Syd-1, controls presynaptic long-term plasticity and the maintenance of olfactory memories in . While mutants could not trigger nanoscopic active zone remodeling under homeostatic challenge and failed to stably potentiate neurotransmitter release, concomitant reduction of Syd-1 rescued all these deficits.
View Article and Find Full Text PDFEur J Transl Myol
August 2023
Department of Biology, Maynooth University, National University of Ireland, Maynooth, Co. Kildare, Ireland; Kathleen Lonsdale Institute for Human Health Research, Maynooth University, Maynooth, Co. Kildare.
The wobbler mouse is a widely used model system of amyotrophic lateral sclerosis and exhibits progressive neurodegeneration and neuroinflammation in association with skeletal muscle wasting. This study has used wobbler brain preparations for the systematic and mass spectrometric determination of proteome-wide changes. The proteomic characterization of total protein extracts from wobbler specimens was carried out with the help of an Orbitrap mass spectrometer and revealed elevated levels of glia cell marker proteins, i.
View Article and Find Full Text PDFJ Alzheimers Dis
July 2023
Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
Background: Altered glutamatergic neurotransmission may contribute to impaired default mode network (DMN) function in Alzheimer's disease (AD). Among the DMN hub regions, frontal cortex (FC) was suggested to undergo a glutamatergic plasticity response in prodromal AD, while the status of glutamatergic synapses in the precuneus (PreC) during clinical-neuropathological AD progression is not known.
Objective: To quantify vesicular glutamate transporter VGluT1- and VGluT2-containing synaptic terminals in PreC and FC across clinical stages of AD.
Neurosci Res
July 2022
Department of Demyelinating Disease and Aging, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira, Tokyo 187-8502, Japan; Department of Neurology and Neurological Science, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo 113-8510, Japan. Electronic address:
Recent evidence suggests that soluble amyloid-β oligomers (AβOs) act as a key factor in the pathogenetic mechanism of Alzheimer's disease (AD). AβOs induce neurotoxic and synaptotoxic effects probably through binding to certain receptors, however it remains unclarified which receptors are most critically involved. In addition, dysregulation in glutamatergic signaling is implicated in AD.
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