Finally, photoactivation experiments revealed that the mutant tau line shows a higher proportion of stationary tau proteins over time suggesting a potential mechanism for the different distribution of mutant proteins or differently phosphorylated proteins in tauopathies. This finding was not related to an effect on microtubule stability as could be seen in western blots by analyzing the degree of tubulin acetylation. Taken together, the data demonstrate that photoactivatable tau proteins provide a useful tool to analyze dynamic properties (with a supportive biochemical correlate) in a living neuronal cell model scenario to help determine the effects of different tau mutations in neurodegenerative diseases. from Annual Meeting of the Study Group Neurochemistry. International Conference of the Gesellschaft fur Biochemie und Molekularbiologie 2006 (GBM 2006): Molecular pathways in health and disease of the nervous system Witten, Germany. 28–30 September 2006