Figure 7.

PPIase activity is essential for FKBP51 to facilitate microtubule formation and tau-mediated microtubule polymerization is enhanced by FKBP51. In vitro microtubule assembly assays were performed using Xenopus oocyte extracts supplemented with rhodamine-labeled tubulin. A, Panels show tubulin structures in sample buffer only or supplemented with 1 μm recombinant WT FKBP51, 1 μm F130A FKBP51, 1 μm FKBP52, nocodazole, or taxol. B, Microtubule (MT) lengths were measured for each condition (n = number of asters measured per condition) using AxioVision software from Zeiss, and values are indicated in micrometers ± SD. ***p < 0.001. C, Panels show tubulin structures in sample buffer only or supplemented with 2.5 μm tau alone or 2.5 μm tau plus 1 μm FKBP51. Tau alone caused dramatic morphologic changes to microtubules, which were accentuated in the presence of FKBP51.