Tau is a microtubule (MT) associated protein (MAP) that is found aggregated into straight (SF) or paired helical (PHF) filaments within neurofibrillary tangle deposits in Alzheimer's disease (AD) and other neurodegenerative disorders. Mutations in the gene encoding tau are associated with the hereditary syndrome FTDP-17 (frontotemporal dementia and Parkinsonism linked to chromosome 17) indicating that tau plays a causative role in the pathogenesis of this and possibly other diseases such as AD. Many of the FTDP-17 linked mutations fall within the MT binding domain (MBD) of tau, a region that contains, depending on the isoform, three or four pseudo-repeats (3R vs. 4R) of a 31 to 32 residue MT interaction motif. These mutations disrupt tau-MT interactions and tau-promoted MT assembly, and several also enhance tau PHF formation in vitro. A different class of FTDP-17 associated mutations influence tau mRNA splicing and alter the ratio of 4R to 3R tau isoforms in vivo, which can both modulate the normal functions of tau and enhance tau aggregation by altering the relative populations of free and MT-bound isoforms. Thus, tau mutations may exert pathogenic effects by interfering with tau function, by enhancing tau aggregation, or by both means. Tau is intrinsically unstructured when free in solution but undergoes structural transitions upon binding to MTs, upon filament formation, and upon associating with lipid membranes. Residual structure in free tau may play an important role in mediating these various intermolecular interactions. We propose to characterize, at high resolution, the structural and dynamic properties of tau in its free state using NMR spectroscopy. We will also elucidate in detail the structure of detergent micelle associated tau and the topology of lipid vesicle and MT-bound tau. We will probe the effects of FTDP-17 linked mutations on the structural properties of free, lipid-associated and MT-bound tau and will use newly designed mutations to elucidate the structural basis for these intermolecular interactions. Our studies will focus on 3R and 4R forms of the tau MBD. The results will clarify the molecular mechanisms underlying both normal tau function and tau induced neurodegeneration and may suggest strategies for developing new therapeutics. This work may also have broader implications for understanding and treating other protein aggregation diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Project (R01)
Project #
5R01AG025440-02
Application #
7097372
Study Section
Neurodegeneration and Biology of Glia Study Section (NDBG)
Program Officer
Miller, Marilyn
Project Start
2005-08-01
Project End
2009-07-31
Budget Start
2006-08-01
Budget End
2007-07-31
Support Year
2
Fiscal Year
2006
Total Cost
$302,676
Indirect Cost
Name
Weill Medical College of Cornell University
Department
Biochemistry
Type
Schools of Medicine
DUNS #
060217502
City
New York
State
NY
Country
United States
Zip Code
10065
Sung, Yoon-Hui; Eliezer, David (2018) Structure and dynamics of the extended-helix state of alpha-synuclein: Intrinsic lability of the linker region. Protein Sci 27:1314-1324
Eliezer, David (2017) Proteins acting out of (dis)order. Elife 6:
Zhao, Jing; Huvent, Isabelle; Lippens, Guy et al. (2017) Glycan Determinants of Heparin-Tau Interaction. Biophys J 112:921-932
Dikiy, Igor; Fauvet, Bruno; Jovi?i?, Ana et al. (2016) Semisynthetic and in Vitro Phosphorylation of Alpha-Synuclein at Y39 Promotes Functional Partly Helical Membrane-Bound States Resembling Those Induced by PD Mutations. ACS Chem Biol 11:2428-37
Chaari, Ali; Eliezer, David; Ladjimi, Moncef (2016) The C-terminal ?-helices of mammalian Hsc70 play a critical role in the stabilization of ?-synuclein binding and inhibition of aggregation. Int J Biol Macromol 83:433-41
Iaea, David B; Dikiy, Igor; Kiburu, Irene et al. (2015) STARD4 Membrane Interactions and Sterol Binding. Biochemistry 54:4623-36
Mahul-Mellier, Anne-Laure; Fauvet, Bruno; Gysbers, Amanda et al. (2014) c-Abl phosphorylates ?-synuclein and regulates its degradation: implication for ?-synuclein clearance and contribution to the pathogenesis of Parkinson's disease. Hum Mol Genet 23:2858-79
Dikiy, Igor; Eliezer, David (2014) N-terminal acetylation stabilizes N-terminal helicity in lipid- and micelle-bound ?-synuclein and increases its affinity for physiological membranes. J Biol Chem 289:3652-65
Barré, Patrick; Eliezer, David (2013) Structural transitions in tau k18 on micelle binding suggest a hierarchy in the efficacy of individual microtubule-binding repeats in filament nucleation. Protein Sci 22:1037-48
Dikiy, Igor; Ramlall, Trudy F; Eliezer, David (2013) ¹H, ¹³C, and ¹?N backbone resonance assignments of the L124D mutant of StAR-related lipid transfer domain protein 4 (StARD4). Biomol NMR Assign 7:245-8

Showing the most recent 10 out of 31 publications