1 By: Dustin Horn
2 Synaptic Plasticity During LearningOverview of a Neuron Short Term Early Long Term Potentiation Late Long Term Potentiation The “Synaptic Tag”
3 The Neuron
4 Function
5 Other Terms Receptors: NMDA and AMPAGlutamate receptors with integrated ion channels Plasticity: change within the synapses that results in new electrical properties Cytoskeleton: Actin fibers within the cell Allow transport Support cell shape
6 Short Term Happen on timescale of secondsActin dependent post-synaptic plasticity
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8 10 % change in shape could significantly change synaptic communicationPossible mechanism: Actin polymerization affects NMDA receptor NMDA receptor affects actin polymerization
9 Early Long Term PotentiationChanges properties of existing cellular processes Proteins move to new locations Proteins are chemically altered Lasts for hours NMDA and AMPA receptors
10 AMPA and NMDA
11 Late Long-Term PotentiationRequires protein synthesis FMRP- Fragile-x Mental Retardation Protein binds to mRNA
12 Unlocking of mRNA Local Glutamate receptors are activatedResults in phosphorylation of FMRP Frees mRNA Local synaptic ribosomes translate proteins
13 ARC/PSD-95 Located in the post-synaptic densityRegulates # of glutamate receptors inserted into plasma membrane
14 BDNF -Brain-Derived Neurotrophic FactorAutocrine signal that regulates: Scaffold Proteins Neuro-transmitter Receptors Inactive synapse elimination
15 “Synaptic Tag” Experiment ProposalmRNA molecules are guided to proper location by a “Synaptic Tag” Transcription in Nucleus Loaded into vesicles Transported along cytoskeleton Molecular Identity is Unknown Hypothesis: Protein attached to FMRP or CAMKII What and where?
16 Tracking Vesicular Movement
17 Magnetic Immuno-Precipitation
18 Gel-Electrophoresis & Mass Spec.
19 Gene Knock Out CRISPR/Cas-9 Transgenic GFP-ARC
20 Immuno-Gold SEM Develop anti-bodies against candidate proteinAdd in gold particle-antibody complex Use SEM to locate protein
21 In Conclusion Neuronal synapses are dynamic structuresChanges last from seconds to weeks Modulation of synapses underlies our ability to learn Not all molecules involved in the processes are known Synaptic “tag” is an important molecule in ability to form long-term memory
22 Questions?
23 References Slides 2-5: Levitan, I. The Neuron: Cell and Molecular Biology. Oxford Univeristy Press Ch 1-4 Slides 6-8:Rapid Actin-Based Plasticity in Dendritic Spines. Fischer, Maria et al.Neuron , Volume 20 , Issue 5 , Slides 9-14: Levitan, I. The Neuron: Cell and Molecular Biology. Oxford Univeristy Press Ch 11, 17, 19 15-16: Ralf Dahm, Manuel Zeitelhofer, Bernhard Götze, Michael A. Kiebler, Paolo Macchi, Visualizing mRNA Localization and Local Protein Translation in Neurons, Methods in Cell Biology, Academic Press, 2008, Volume 85, Pages Slides 15-20: Cox, M. Molecular Biology: Principles and Practice. W.H. Freeman and company. New York
24 Pictures Slides 2,6-8: Figures from3:http://web.stanford.edu/group/hopes/cgi-bin/hopes_test/wp-content/uploads/2010/06/new- connections3-revised.jpg 4:https://qbi.uq.edu.au/files/7758/Synapse-QBI-brain-neuroscience.jpg 10:https://media.licdn.com/mpr/mpr/AAEAAQAAAAAAAAmCAAAAJGIxYzJmN2VlLWZiM2Et NGM5My05ZTA4LTk0NGMyOGM4OTYwOA.png 16: Figure from: 17:https://www.thermofisher.com/us/en/home/life-science/protein-biology/protein-assays- analysis/immunoprecipitation/_jcr_content/MainParsys/accordion_5def/itemspar/accordionit em_ddcd/itemParsys/textimage_eeff/backgroundimg.img.jpg/ jpg 18:https://i.ytimg.com/vi/7cLDtnbnrg0/maxresdefault.jpg; 19:https://www.mirusbio.com/assets/figures/crispr-cas9-genome-editing.png 20: Figure from: