The long term goals of the Principal Investigator are to investigate the changes in the tau molecule that lead to a decrease in its normal functions and increase its pathological ability to self-assemble into filaments found in many neurodegenerative disorders. The purpose of this proposal is to determine the effects of changes in phosphorylation that are observed in Alzheimer's disease (AD) on the functions of the tau protein. These experiments will have an immediate impact in AD research since there is a current controversy over the role of phosphorylation and """"""""hyperphosphorylation"""""""" in the polymerization of tau into filaments found in AD pathology. We hypothesize that site-specific phosphorylation events can change the conformation of tau and create variants of the molecule that have an increased ability to polymerize, a decreased ability to bind to and stabilize microtubules, or both. We also hypothesize that the phosphorylation of the tau molecule will increase the stability of tau filaments, which could account for their longevity in affected neurons in AD. We will test these hypotheses by accomplishing the following specific aims: 1) The effects of site-specific phosphorylation events found in AD on the polymerization of the longest isoform of tau and the stability of those filaments will be assessed using an in vitro polymerization paradigm monitored by laser light scattering and quantitative electron microscopy. 2) The effects of AD-like phosphorylation on the ability of tau to bind to and stabilize microtubules will be assessed using tubulin binding assays and microtubule polymerization assays in the presence of phospho-variants of tau. 3) The effects of site-specific phosphorylation events will be modeled in the background of the six major isoforms of tau since these isoforms can be differentially involved in neurodegenerative diseases. 4) The effects of """"""""hyperphosphorylation"""""""" will be modeled to determine the effects of multiple phosphorylation events on the polymerization and stability of tau filaments. 5) The effects of phosphorylation that occur after tau polymerization on the stability of tau filaments will be investigated using quantitative electron microscopy.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Project (R01)
Project #
1R01AG022428-01
Application #
6672384
Study Section
Special Emphasis Panel (ZRG1-MDCN-1 (01))
Program Officer
Snyder, Stephen D
Project Start
2003-09-01
Project End
2008-07-31
Budget Start
2003-09-01
Budget End
2004-07-31
Support Year
1
Fiscal Year
2003
Total Cost
$292,313
Indirect Cost
Name
University of Kansas Lawrence
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
076248616
City
Lawrence
State
KS
Country
United States
Zip Code
66045
Voss, Kellen; Combs, Benjamin; Patterson, Kristina R et al. (2012) Hsp70 alters tau function and aggregation in an isoform specific manner. Biochemistry 51:888-98
Combs, Benjamin; Voss, Kellen; Gamblin, T Chris (2011) Pseudohyperphosphorylation has differential effects on polymerization and function of tau isoforms. Biochemistry 50:9446-56
Sun, Qian; Gamblin, T Chris (2009) Pseudohyperphosphorylation causing AD-like changes in tau has significant effects on its polymerization. Biochemistry 48:6002-11
Voss, Kellen; Gamblin, T Chris (2009) GSK-3beta phosphorylation of functionally distinct tau isoforms has differential, but mild effects. Mol Neurodegener 4:18
Rankin, Carolyn A; Sun, Qian; Gamblin, T Chris (2008) Pre-assembled tau filaments phosphorylated by GSK-3b form large tangle-like structures. Neurobiol Dis 31:368-77
Rankin, Carolyn A; Gamblin, T Chris (2008) Assessing the toxicity of tau aggregation. J Alzheimers Dis 14:411-6
Rankin, Carolyn A; Sun, Qian; Gamblin, Truman C (2007) Tau phosphorylation by GSK-3beta promotes tangle-like filament morphology. Mol Neurodegener 2:12
Carlson, Shaun W; Branden, Mike; Voss, Kellen et al. (2007) A complex mechanism for inducer mediated tau polymerization. Biochemistry 46:8838-49
Sarthy, Jay; Gamblin, T Chris (2006) A light scattering assay for arachidonic acid-induced tau fibrillization without interfering micellization. Anal Biochem 353:150-2
Rankin, Carolyn A; Sun, Qian; Gamblin, T Chris (2005) Pseudo-phosphorylation of tau at Ser202 and Thr205 affects tau filament formation. Brain Res Mol Brain Res 138:84-93

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