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Mutated tau binds less avidly to microtubules than wildtype tau in living cells
Author(s) -
Nagiec E. Ewa,
Sampson Kathleen E.,
Abraham Irene
Publication year - 2001
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/1097-4547(20010201)63:3<268::aid-jnr1020>3.0.co;2-e
Subject(s) - microtubule , cytoplasm , tau protein , wild type , biology , cytoskeleton , mutant , microbiology and biotechnology , transfection , tauopathy , tubulin , cell culture , cell , genetics , neurodegeneration , alzheimer's disease , gene , pathology , medicine , disease
Some forms of genetically inherited dementia, including frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP‐17), are caused by mutations in tau. We have examined several mutations in the microtubule‐binding portion of tau for their effect on microtubule binding, cellular distribution and cytoskeletal structure in mammalian cells. Using constructs coding for mutant (P301L and V337M) and wildtype human tau fused to a green fluorescent protein analog (EGFP) we followed the disposition of tau in live cells after transient transfection using confocal microscopy. Most of the tau protein localized to structures that resembled microtubules or microtubule bundles and co‐localized with tubulin. At 3 days post‐transfection mutant tau proteins showed a higher abundance of free tau in the cytoplasm than did wildtype tau. Cells expressing the P301L mutation showed proportionally more cytoplasmic localization of tau. Confirming these results, fractionated cells with mutant tau had a higher percentage of tau in the cytoplasmic compartment as compared to the cytoskeletal compartment. Cells with wildtype tau had most tau in the cytoskeletal fraction. Because the mutations (V337M, P301L) are associated with genetic tauopathies, these results suggest that a factor in disease etiology of genetic tauopathies and other dementias with altered tau is a greater abundance of tau in the cytoplasm due to decreased binding to microtubules. This increased cytoplasmic presence may be a significant factor in promoting tau aggregation. J. Neurosci. Res. 63:268–275, 2001. © 2001 Wiley‐Liss, Inc.