Monitoring tau-tubulin interactions utilizing second harmonic generation in living neurons.
Tau is a microtubule associated protein that is localized to the axon in neurons. During pathological conditions, including frontotemporal dementia (FTD), a shift in tau isoforms occurs that leads to enhanced expression of a form of tau with four (rather than three) microtubule binding repeats; this has been postulated to alter microtubule structure. Second harmonic generation (SHG) is a technique that allows the visualization of intact microtubules in axons of living neurons without the need for labeling or fixing. We examined how the presence of exogenous tau influences SHG in living neurons. Our results show that the presence of tau significantly enhances SHG, specifically in neuronal axons, despite the presence of tau throughout the entire cell. Our data also suggest that the presence or absence of the fourth microtubule binding repeat does not significantly alter tau's ability to enhance SHG. These results provide evidence that SHG is a useful, noninvasive tool to study tau-microtubule interactions in axons; further, it appears that tau overexpression, rather than specific isoforms, is the major contributor to tau-induced changes in axonal microtubule SHG signal.
Stoothoff
William H
WH
Massachusetts General Hospital-Harvard Medical School, Department of Neurology, Charlestown, Massachusetts 02129, USA.
Bacskai
Brian J
BJ
Hyman
Bradley T
BT
D000818:Animals; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology* / Q000378:metabolism*; D051379:Mice; D008856:Microscopy, Fluorescence / Q000379:methods*; D009474:Neurons / Q000166:cytology* / Q000378:metabolism*; D025941:Protein Interaction Mapping / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014404:Tubulin / Q000378:metabolism* / Q000648:ultrastructure; D016875:tau Proteins / Q000378:metabolism* / Q000648:ultrastructure
D014404:Tubulin; D016875:tau Proteins