The regulated production of proteins in neurons in response to extracellular stimuli has emerged as an important and common mechanism for the modification of synapses. In addition, ample evidence now supports that proteins can be made within neuronal subcompartments such as dendrites. However, the spatial scale over which protein translation is independently regulated and whether it is truly controlled locally in dendrites by focal synaptic activity are unknown. Furthermore, the pathways that link synaptic stimuli to the control of protein production are unclear. In many cell types, the regulation of protein translation in response to extracellular stimuli occurs through the mTOR pathway. An important role for the mTOR pathway is neurons is indicated by the association of mutations in the pathway with the human neurological disorders Tuberous Sclerosis Complex (TSC) and Lhermitte-Duclos Disease (LDD) and the finding that pharmacological inhibitors of mTOR interfere with several forms of long-term synaptic plasticity. The research proposed here will examine the regulation of the mTOR pathway by synaptic stimuli and its role controlling dendritic and synaptic growth. Traditional biochemcial approaches will be used to systematically map the sets of stimuli that activate or repress protein translation in neurons. 2-photon uncaging of; glutamate will be used to focally activate synapses and to probe the spatial scale of regulation of protein translation in dendrites. The perturbation of dendritic spine growth and synaptic plasticity resulting from interfering with the mTOR pathway and from genetic mutations associated with TSC and LDD will be determined. Lastly, electrophysiogical analysis and calcium imaging will be used to uncover functional defects arising from interfering with the mTOR pathway.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS052707-04
Application #
7739468
Study Section
Synapses, Cytoskeleton and Trafficking Study Section (SYN)
Program Officer
Morris, Jill A
Project Start
2007-02-01
Project End
2011-11-30
Budget Start
2009-12-01
Budget End
2011-11-30
Support Year
4
Fiscal Year
2010
Total Cost
$367,074
Indirect Cost
Name
Harvard University
Department
Biology
Type
Schools of Medicine
DUNS #
047006379
City
Boston
State
MA
Country
United States
Zip Code
02115
Bateup, Helen S; Johnson, Caroline A; Denefrio, Cassandra L et al. (2013) Excitatory/inhibitory synaptic imbalance leads to hippocampal hyperexcitability in mouse models of tuberous sclerosis. Neuron 78:510-22
Bateup, Helen S; Takasaki, Kevin T; Saulnier, Jessica L et al. (2011) Loss of Tsc1 in vivo impairs hippocampal mGluR-LTD and increases excitatory synaptic function. J Neurosci 31:8862-9
Cheng, Jie; Zhou, Xiaobo; Miller, Eric L et al. (2010) Oriented Markov random field based dendritic spine segmentation for fluorescence microscopy images. Neuroinformatics 8:157-70
Beck, Dominik; Zhou, Xiaobo; Pham, Tuan et al. (2009) An Image Driven Systems Biology Approach for Neurodegenerative Disease Studies in the TSC-mTOR Pathway. IEEE NIH Life Sci Syst Appl Workshop :36-39
Sturgill, James F; Steiner, Pascal; Czervionke, Brian L et al. (2009) Distinct domains within PSD-95 mediate synaptic incorporation, stabilization, and activity-dependent trafficking. J Neurosci 29:12845-54
Steiner, Pascal; Higley, Michael J; Xu, Weifeng et al. (2008) Destabilization of the postsynaptic density by PSD-95 serine 73 phosphorylation inhibits spine growth and synaptic plasticity. Neuron 60:788-802
Xu, Weifeng; Schluter, Oliver M; Steiner, Pascal et al. (2008) Molecular dissociation of the role of PSD-95 in regulating synaptic strength and LTD. Neuron 57:248-62
Han, Sangyeul; Witt, Rochelle M; Santos, Tulio M et al. (2008) Pam (Protein associated with Myc) functions as an E3 ubiquitin ligase and regulates TSC/mTOR signaling. Cell Signal 20:1084-91
Cheng, Jie; Zhou, Xiaobo; Miller, Eric et al. (2007) A novel computational approach for automatic dendrite spines detection in two-photon laser scan microscopy. J Neurosci Methods 165:122-34
Zhang, Yong; Zhou, Xiaobo; Witt, Rochelle M et al. (2007) Dendritic spine detection using curvilinear structure detector and LDA classifier. Neuroimage 36:346-60