Discipline: Biological Sciences
Subcategory: Cell and Molecular Biology
Katherine Varela - University of Michigan
Co-Author(s): 1) J.C. Althaus2,3, E.L. Stuenkel1-2, M.A. Sutton1-3. 1BP-ENDURE Summer Fellowship Program, 2) Department of Molecular and Integrative Physiology, 3) Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, USA.
Homeostatic Plasticity promotes stability in neural circuits through adaptive changes in neural excitability and synaptic function. When activity is elevated, compensatory downscaling of synaptic function can push firing rates back to average levels. When activity is diminished, upscaling of synaptic function and excitability can restore stable activity patterns in networks. Our previous work has demonstrated that AMPA receptor blockade drives an increase in presynaptic neurotransmitter release through the mTORC1-dependent postsynaptic synthesis and release of Brain Derived Neurotrophic Factor (BDNF). Recently, we have found a critical presynaptic role of the ubiquitin proteasome System (UPS) in gating these BDNF-dependent effects on release. Here, we investigate a potential role for a negative regulator of synaptic vesicle mobility and release – Tomosyn-1 – as a target for UPS degradation downstream of BDNF-induced signaling. Rat hippocampal neurons (~21 DIV) were treated with BDNF (250 ng/ml; 60 min) in the presence or absence of the proteasome inhibitor lactacystin (10 uM) and stained for Tomosyn-1, as well as VGLUT1 to identify excitatory presynaptic terminals. We found that BDNF induces a significant loss of Tomosyn-1 expression at VGLUT-1 positive terminals, an effect that is blocked by coincident inhibition of proteasome activity. We are currently examining the dynamic regulation of Tomosyn-1 expression by monitoring expression of recombinant Tomosyn-1 coupled to fluorescent and photo convertible tags. Our results indicate that BDNF negatively regulates Tomosyn-1 expression in presynaptic terminals via the UPS, which may link postsynaptic signaling to alterations in neurotransmitter release.Not Submitted
Funder Acknowledgement(s): Supported by: BP-Endure 5R25NS080686-07 NIH - R01NS097498
Faculty Advisor: Dr. Michael Sutton, email@example.com
Role: During my summer internship at the University of Michigan I worked under Dr. Michael Sutton researching Homeostatic Plasticity of synaptic connectivity. During this project, I took lead responsibility of conducting the experiments by, preparing and treating the neuronal cells with ICC protocol, using confocal microscopy to image post ICC, and conducted data analysis using IMAGE J, FIJI, and Excel. Moreover, when the project reached completion, I presented the data findings of my research both orally and in poster format, at the University of Michigan, and Society for Neuroscience.