2007 — 2013 |
Juo, Peter C |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. R56Activity Code Description: To provide limited interim research support based on the merit of a pending R01 application while applicant gathers additional data to revise a new or competing renewal application. This grant will underwrite highly meritorious applications that if given the opportunity to revise their application could meet IC recommended standards and would be missed opportunities if not funded. Interim funded ends when the applicant succeeds in obtaining an R01 or other competing award built on the R56 grant. These awards are not renewable. |
Molecular and Genetic Analysis of Cdk-5 Function in Synaptic Transmission @ Tufts University Boston
[unreadable] DESCRIPTION (provided by applicant): The long-term goal of this research is to identify and understand the genes and mechanisms that regulate CDK-5 function in synaptic transmission. The cyclin-dependent kinase CDK-5 has diverse cellular functions during development, contributes to several neurodegenerative disorders, and has recently emerged as an important regulator of synapse function and plasticity. The focus of this proposal is to investigate the mechanisms by which CDK-5 regulates glutamate receptor (GluR) trafficking and to identify upstream regulatory signals that control CDK-5 function at the synapse. Activity-dependent regulation of the localization and abundance of synaptic GluRs directly affects synaptic strength and is thought to underlie information storage and processing in the brain. Aberrant regulation of GluRs may contribute to excitotoxicity in ischemia (lack of blood flow), stroke and neurodegenerative disorders. Thus, it is important to define the basic cell biological mechanisms that regulate GluR transport. We use C. elegans as a genetic model to study the genes and mechanisms that regulate synaptic transmission and GluR trafficking in vivo. Advantages of C. elegans include the compact genome (i.e. less gene redundancy), powerful genetic tools and ability of the animal to tolerate severe reductions in nervous system function. Our preliminary studies indicate that CDK-5 regulates the abundance of the scaffolding protein LIN-10/Mint-1 and the glutamate receptor GLR-1 at synapses in vivo. LIN-10/Mint-1 is a PTB and PDZ domain-containing protein that has been localized to the golgi and synapses and has a conserved role in polarized transport in neurons and epithelia. In this proposal, we will (1) Determine which step of GLR-1 trafficking is regulated by CDK-5, (2) Define the mechanisms by which CDK-5 regulates the abundance of LIN-1u/Mint-1, (3) Characterize the upstream regulatory signals that control CDK-5 function. This research may reveal novel targets for therapeutic intervention to control GluR-mediated excitotoxicity after stroke and ischemic (lack of blood flow) brain injury. In addition, since CDK-5 regulates neuronal development and function, and contributes to Alzheimer's Disease and amyotrophic lateral sclerosis (ALS), understanding the mechanisms that regulate CDK-5 activity and how it controls synaptic transmission in healthy neurons will help reveal the pathogenesis underlying the role of CDK-5 in neurodegeneration. [unreadable] [unreadable]
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0.931 |
2014 — 2018 |
Juo, Peter |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Regulation of Glutamate Receptors At Synapses by Wd40 Repeat Proteins and the Deubiquitinating Enzyme Usp-46 in C. Elegans
This project will increase our fundamental understanding of how neurons communicate with each other at the molecular level. Neuronal communication is essential for normal brain function and for learning and memory. Neurons communicate with each other at specialized junctions called synapses. Neurons release chemical signals, such as the neurotransmitter glutamate, which are received by downstream neurons via specialized protein detectors called glutamate receptors (GluRs). Changing the number or levels of GluRs at the synapse allows neurons to alter their communication, which enables the brain to learn, adapt and store memories. The specific focus of this project is to study how a new family of proteins control the number of GluRs at the synapse by preventing their degradation via the ubiquitin system. Ubiquitin is a tag that can be attached and removed from other proteins in a highly controlled manner. Proteins marked with ubiquitin are targeted to the cellular trash for degradation. This proposal studies how three proteins function together to specifically remove ubiquitin from GluRs, thus rescuing them from degradation and increasing receptor levels at the synapse. In addition, this project develops and launches an innovative, discovery-based Molecular Genetics and Cell Biology Lab Course for undergraduates, trains graduate students and postdoctoral fellows, and provides research opportunities for high school teachers and minority undergraduates.
Ubiquitin is an important regulator of synapse development and function. There are about 100 deubiquitinating enzymes (DUBs) that remove ubiquitin from other proteins, however very little is known about the DUBs that function at the synapse. The awardee's lab recently identified USP-46 as the first DUB to regulate GluRs. This proposal investigates how two proteins, WDR-20 and WDR-48, interact and regulate the activity of USP-46 to control GluRs levels at the synapse, and tests how these molecular changes affect behavior. This study uses genetic, biochemical, quantitative imaging and behavioral methods to study GluRs in the well-established genetic model organism C. elegans. Advantages of C. elegans include powerful genetic tools, a simple and defined nervous system, and simple behavioral assays to correlate neuronal function with whole animal behavior. The basic mechanisms involved in synapse development and function are conserved from nematodes to humans. Understanding how molecular changes at the synapse impact neuronal communication and behavior will provide fundamental information that could be applied to improve learning and memory, and to begin to uncover the molecular basis of learning and behavioral disorders.
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1 |
2017 — 2018 |
Juo, Peter C |
R21Activity Code Description: To encourage the development of new research activities in categorical program areas. (Support generally is restricted in level of support and in time.) |
An Optogenetic Behavioral Screen For Conserved Genes That Regulate Glutamatergic Synapses @ Tufts University Boston
Project Summary Glutamate is the major excitatory neurotransmitter in the brain. The development and function of glutamatergic synapses is essential for proper neuronal connectivity and brain function, including learning and memory. Recent data suggest that defects in synapse development and function contribute to several neurodevelopmental and neuropsychiatric diseases such as intellectual disability, autism spectrum disorders, Alzheimer's disease and schizophrenia. In addition, excessive activation of glutamate signaling can lead to excitotoxic cell death in ischemia, stroke and neurodegenerative diseases. Thus, it is important to understand the cell biological and molecular mechanisms involved in regulating glutamatergic synapses. While much progress has been made identifying genes that regulate glutamatergic synapse development and function in vitro using neuronal cultures, less is known about the in vivo function of many of those genes. Challenges of in vivo analysis include the fact that mouse gene knock-outs do not always lead to the same dramatic synaptic defects observed in vitro, perhaps due to gene redundancy, and furthermore, compound knock-outs of gene families often lead to embryonic lethality further hindering phenotypic analyses. We use C. elegans as a genetic model to study genes and mechanisms that regulate glutamatergic synapses in vivo. Advantages of C. elegans include less gene redundancy, powerful genetic tools, a simple defined nervous system, and the ability of the animal to tolerate severe reductions in neuronal function. The goal of this exploratory proposal is to identify novel genes and mechanisms that regulate glutamatergic synapse development and function in vivo. In Aim 1, we combine several strengths of C. elegans and develop an innovative, optogenetic behavioral screen, based on a simple glutamatergic behavior, to identify conserved neuronal genes that regulate glutamatergic synapes. We have completed a pilot screen of genes with cell-adhesion molecule domains and identified several strong candidates, including the Ig-domain-containing, VEGF (Vascular Endothelial Growth Factor) receptor-related genes, ver-1 and ver-4. In Aim 2, we investigate the role of ver-1 and ver-4 in regulating glutamatergic synapses to illustrate our strategy for analyzing top candidates from our screen. Understanding how VEGFR signaling regulates glutamatergic synapses in C. elegans will be informative given that worms do not possess a cardiovascular system where VEGF has traditionally been shown to act. Identifying novel genes and fundamental mechanisms that regulate glutamatergic synapses may provide potential therapeutic targets for treatment of neurological diseases.
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0.931 |