Figure 10.

Tau expression reduces the mobility of AnxA2 in growth cones. (A) Immunoblot showing the expression of PAGFP-tagged AnxA2 at the expected size (arrows). Endogenous annexin is indicated by the arrowhead. Tubulin is stained as loading control. (B) Fluorescence micrographs of PC12 cells stably expressing FLAG-tagged wt tau or R406W tau after infection with a lentivirus encoding AnxA2–PAGFP. Cells were fixed with paraformaldehyde and stained with antibodies against GFP (for AnxA2–PAGFP) and the FLAG-epitope (for tau). Close-ups of the tips of processes are shown on the right. Note that AnxA2–PAGFP showed an enrichment at the tip of neurites similar to endogenous AnxA2. Wt tau colocalized with AnxA2–PAGFP at the tip while R406W tau was absent (arrowheads). Bar, 10 µm. (C) Retention of AnxA2–PAGFP at the tip of neuronally differentiated PC12 cells stably expressing FLAG-tagged wt tau, R406W tau, or control cells. Note the increased retention of AnxA2–PAGFP* in wt tau, but not in R406W tau–expressing cells or control cells. Values are shown as mean ± SEM (error bars). ***, P < 0.001; *, P < 0.05 (n = 6–27). Experiments were performed with the 352 tau isoform.