The long term objectives of this research program are to understand the mechanisms by which the cytoskeleton becomes abnormal in Alzheimer's diesease and, perhaps, in normal aged brains. We are particularly interested in the role phosphorylation of cytoskeletal polypeptides might play in mediating the ability of the polypeptides to interact in an appropriate fashion to form noraml cytoskeletal organelles. A major hypothesis we will be testing is that alterations in the state of phosphorylation of cytoskeletal polypeptides in Alzheimer's disease is one step leading to the formation of the paired helical filaments (PHF) in the neurofibrillary tangle (NFT) and neuritic plague (NP) that are a hallmark of the pathology of this disease. Results to date indicate that modifications in the state of phosphorylation of the tau family of microtubule-associated proteins may be a step in the pathogenesis of the NFT and NP. In this program we will use a variety of biochemcial procedures to isolate and purify individual tau isoforms and fragments from AD brains to use in bioassay with regard to their properties in stimulating the assembly and stability of microtubules as a test for those fragments likely to contain biologically relevant modified sites. We will also compare the detailed pattern of tau cytochemistry in buffer and alkaline phosphatase treated NFT and NP at the electron microscopic level to ask whether or not sites accessible to anti-tau without dephosphorylation represent early-forming tangles with relatively unmodified tau associated with some straignt tubules, whereas those sites exposed after dephosphorylation represent tau modified by more extensive phosphorylation to participate in the formation of networks of PHF. We will use phosphorylation by exogenous and endogenous protein kinase activities of tissue sections and membrane blots to further identify and characterize sites on the tau family of polypeptides which might be modified in AD and, potentially, in aged human brains.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Project (R01)
Project #
5R01AG006383-02
Application #
3117407
Study Section
Neurological Sciences Subcommittee 1 (NLS)
Project Start
1988-04-01
Project End
1991-03-31
Budget Start
1989-04-01
Budget End
1990-03-31
Support Year
2
Fiscal Year
1989
Total Cost
Indirect Cost
Name
Emory University
Department
Type
Schools of Medicine
DUNS #
042250712
City
Atlanta
State
GA
Country
United States
Zip Code
30322
Lu, Q; Soria, J P; Wood, J G (1993) p44mpk MAP kinase induces Alzheimer type alterations in tau function and in primary hippocampal neurons. J Neurosci Res 35:439-44
Lu, Q; Wood, J G (1993) Functional studies of Alzheimer's disease tau protein. J Neurosci 13:508-15
Lu, Q; Wood, J G (1993) Characterization of fluorescently derivatized bovine tau protein and its localization and functions in cultured Chinese hamster ovary cells. Cell Motil Cytoskeleton 25:190-200
Roden, R L; Donahue, S P; Schwartz, G A et al. (1991) 200 kD neurofilament protein and synapse elimination in the rat soleus muscle. Synapse 9:239-43
Wood, J G; Zinsmeister, P (1991) Tyrosine phosphorylation systems in Alzheimer's disease pathology. Neurosci Lett 121:12-6
Wood, J G; Zinsmeister, P (1989) Immunohistochemical evidence for reorganization of tau in the plaques and tangles in Alzheimer's disease. Histochem J 21:659-62
Tillotson, M L; Wood, J G (1989) Phosphotyrosine antibodies specifically label ameboid microglia in vitro and ramified microglia in vivo. Glia 2:412-9
Scanlon, M; Laster, S M; Wood, J G et al. (1989) Cytolysis by tumor necrosis factor is preceded by a rapid and specific dissolution of microfilaments. Proc Natl Acad Sci U S A 86:182-6
Tillotson, M L; Wood, J G (1989) Tyrosine phosphorylation in the postnatal rat brain: a developmental, immunohistochemical study. J Comp Neurol 282:133-41
Pollock, N J; Wood, J G (1988) Differential sensitivity of the microtubule-associated protein, tau, in Alzheimer's disease tissue to formalin fixation. J Histochem Cytochem 36:1117-21