Swimming against the Tide: Mobility of the Microtubule-Associated Protein Tau in Neurons

• DOI: 10.1523/jneurosci.0927-07.2007
• Publication Date: 2007-09-12T16:38:31Z
• Authors: Sven Konzack; Edda Thies; Alexander Marx; Eva-Maria Mandelkow; Eckhard Mandelkow
• Keywords: Axoplasmic transport; Neurite; Growth cone; Tau protein; Photobleaching

Long-haul transport along microtubules is crucial for neuronal polarity, and defects cause neurodegeneration. Tau protein stabilizes microtubule tracks, but in Alzheimer's disease it aggregates becomes missorted into the somatodendritic compartment. can inhibit axonal by obstructing motors on microtubules, yet tau itself still move axons. We therefore investigated movement live-cell fluorescence microscopy, FRAP (fluorescence recovery after photobleaching), FSM speckle microscopy). highly dynamic, with diffusion coefficients of ∼3 μm 2 /s dwell times ∼4 s. This facilitates entry axons over distances millimeters periods days. For longer times, two mechanisms are observed. At low near-physiological levels, cotransported fragments from cell bodies axons, moving at instantaneous velocities ∼1 μm/s. high concentrations, forms local accumulations bidirectionally ∼0.3 These clusters first appear distal endings may indicate an early stage neurite degeneration.