Large clostridial cytotoxins and protein overexpression were used to probe for involvement of Ras-related GTPases (guanosine triphosphate) in synaptic transmission in cultured rat hippocampal neurons. The toxins TcdA-10463 (inactivates Rho, Rac, Cdc42, Rap) and TcsL-1522 (inactivates Ral, Rac, Ras, R-Ras, Rap) both inhibited autaptic responses. In a proportion of the neurons (25%, TcdA-10463; 54%, TcsL-1522), the inhibition was associated with a shift from activity-dependent depression to facilitation, indicating that the synaptic release probability was reduced. Overexpression of a dominant negative Ral mutant, Ral A28N, caused a strong inhibition of autaptic responses, which was associated with a shift to facilitation in a majority (80%) of the neurons. These results indicate that Ral, along with at least one other non-Rab GTPase, participates in presynaptic regulation in hippocampal neurons.
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http://dx.doi.org/10.1097/01.wnr.0000186594.87328.c8 | DOI Listing |
Adv Sci (Weinh)
December 2024
Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, 400016, China.
Current antiepileptic drugs are ineffective in one-third of patients with epilepsy; however, identification of genes involved in epilepsy can enable a precision medicine approach. Here, it is demonstrated that downregulating D-2-hydroxyglutarate dehydrogenase (D2HGDH) enhances susceptibility to epilepsy. Furthermore, its potential involvement in the seizure network through synaptic function modulation is investigated.
View Article and Find Full Text PDFSci Rep
December 2024
Neurobiology Division, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK.
Proximity-dependent biotinylation coupled with mass spectrometry enables the characterization of subcellular proteomes. This technique has significantly advanced neuroscience by revealing sub-synaptic protein networks, such as the synaptic cleft and post-synaptic density. Profiling proteins at this detailed level is essential for understanding the molecular mechanisms of neuronal connectivity and transmission.
View Article and Find Full Text PDFSci Rep
December 2024
Department of Psychology and Neuroscience, Dalhousie University, Halifax, B3H 4R2, Canada.
The parasitic wasp, Cotesia congregata, manipulates the behaviour of its host, the caterpillar Manduca sexta. The female wasp injects her eggs and a symbiotic virus (i.e.
View Article and Find Full Text PDFNat Commun
December 2024
Nanobiology Institute, Yale University, West Haven, CT, USA.
Neurotransmitters are released from synaptic vesicles with remarkable precision in response to presynaptic calcium influx but exhibit significant heterogeneity in exocytosis timing and efficacy based on the recent history of activity. This heterogeneity is critical for information transfer in the brain, yet its molecular basis remains poorly understood. Here, we employ a biochemically-defined fusion assay under physiologically relevant conditions to delineate the minimal protein machinery sufficient to account for various modes of calcium-triggered vesicle fusion dynamics.
View Article and Find Full Text PDFGenetics
December 2024
Department of Genetics and Biochemistry and Center for Human Genetics, Clemson University, 114 Gregor Mendel Circle, Greenwood, SC 29646, USA.
Mucopolysaccharidosis type IIIB (MPS IIIB) is a rare lysosomal storage disorder caused by defects in alpha-N-acetylglucosaminidase (NAGLU) and characterized by severe effects in the central nervous system. Mutations in NAGLU cause accumulation of partially degraded heparan sulfate in lysosomes. The consequences of these mutations on whole genome gene expression and their causal relationships to neural degeneration remain unknown.
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