Protein ubiquitination has emerged as a crucial mechanism for controlling development and function of neuronal circuits, and its defective regulation has been implicated in the pathogenesis of a variety of neurodegenerative diseases, including Parkinson's disease, Alzheimer's disease, Huntington's disease, and amyotrophic lateral sclerosis. However, very little is presently known about the molecular machinery that controls protein ubiquitination in neurons. In the ubiquitin-proteasome pathway, substrate proteins are marked for degradation in the proteasome by covalent linkage to ubiquitin, a 76-amino acid polypeptide. The ubiquitination process involves a highly specific enzyme cascade in which ubiquitin is first activated by an E1 ubiquitin-activating enzyme, then transferred to an E2 ubiquitin-conjugating enzyme, and finally ligated to the substrate by an E3 ubiquitin-protein ligase. Of these enzymes, E3 ligase is the most important player because it determines the specificity of ubiquitin-mediated protein degradation. The importance of E3 ligases in neurodegenerative disorders is highlighted by recent findings that mutations in the E3 ligase parkin are responsible for a familial form of Parkinson's disease. In a search for neuronal proteins that regulate the neurotransmitter release machinery component SNAP-25, the applicant has discovered a novel protein, called Spring. Spring is a neuron-specific member of the RING-B-box-coiled-coil (RBCC) protein family. The importance of the RBCC family is underscored by the identification of the mutations in several RBCC proteins as the causes for a number of human diseases, including Opitz syndrome, Mulibrey nanism, and familial Mediterranean fever. In this project, the applicant will use a combination of biochemical, proteomic, molecular biological, and cell biological approaches to test the hypothesis that Spring functions as a novel E3 ubiquitin-protein ligase to regulate the turnover of the neurotransmitter release machinery. In addition, this project will characterize neuronal distribution and synaptic localization of Spring, and explore the possible involvement of this novel protein in Alzheimer's disease and Parkinson's disease. Successful completion of proposed studies will yield novel insights into the molecular mechanisms that control neuronal protein ubiquitination and neurotransmitter release, and provide fundamental information towards our ultimate goal of understanding and treating numerous neurological diseases and psychiatric disorders.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS047199-05
Application #
7341059
Study Section
Molecular, Cellular and Developmental Neurosciences 2 (MDCN)
Program Officer
Sutherland, Margaret L
Project Start
2003-12-01
Project End
2010-11-30
Budget Start
2007-12-01
Budget End
2010-11-30
Support Year
5
Fiscal Year
2008
Total Cost
$335,479
Indirect Cost
Name
Emory University
Department
Pharmacology
Type
Schools of Medicine
DUNS #
066469933
City
Atlanta
State
GA
Country
United States
Zip Code
30322
Whatley, Brandi R; Li, Lian; Chin, Lih-Shen (2008) The ubiquitin-proteasome system in spongiform degenerative disorders. Biochim Biophys Acta 1782:700-12
Olzmann, J A; Li, L; Chin, L S (2008) Aggresome formation and neurodegenerative diseases: therapeutic implications. Curr Med Chem 15:47-60
Lee, James T; Wheeler, Tiffany C; Li, Lian et al. (2008) Ubiquitination of alpha-synuclein by Siah-1 promotes alpha-synuclein aggregation and apoptotic cell death. Hum Mol Genet 17:906-17
Pridgeon, Julia W; Olzmann, James A; Chin, Lih-Shen et al. (2007) PINK1 protects against oxidative stress by phosphorylating mitochondrial chaperone TRAP1. PLoS Biol 5:e172
Olzmann, James A; Bordelon, Jill R; Muly, E Chris et al. (2007) Selective enrichment of DJ-1 protein in primate striatal neuronal processes: implications for Parkinson's disease. J Comp Neurol 500:585-99
Olzmann, James A; Li, Lian; Chudaev, Maksim V et al. (2007) Parkin-mediated K63-linked polyubiquitination targets misfolded DJ-1 to aggresomes via binding to HDAC6. J Cell Biol 178:1025-38
Kim, Bong Yoon; Olzmann, James A; Barsh, Gregory S et al. (2007) Spongiform neurodegeneration-associated E3 ligase Mahogunin ubiquitylates TSG101 and regulates endosomal trafficking. Mol Biol Cell 18:1129-42
Choi, Joungil; Sullards, M Cameron; Olzmann, James A et al. (2006) Oxidative damage of DJ-1 is linked to sporadic Parkinson and Alzheimer diseases. J Biol Chem 281:10816-24
Choi, Joungil; Levey, Allan I; Weintraub, Susan T et al. (2004) Oxidative modifications and down-regulation of ubiquitin carboxyl-terminal hydrolase L1 associated with idiopathic Parkinson's and Alzheimer's diseases. J Biol Chem 279:13256-64
Olzmann, James A; Brown, Keith; Wilkinson, Keith D et al. (2004) Familial Parkinson's disease-associated L166P mutation disrupts DJ-1 protein folding and function. J Biol Chem 279:8506-15