Figure 1

Spreading of cofilin along dendrites in the resting state.

Photoactivatable green fluorescent protein (PAGFP)-cofilin fusion proteins were photoactivated (ten times at 5 Hz for 1 ms each, repeated twice with a 10 s interval). (A,C,E) Images of dendrites expressing mKeima and wild-type (WT) PAGFP-cofilin (A), PAGFP-(S3A) cofilin (C), or PAGFP-(S3E) cofilin (E). White arrowheads mark an individual photoactivated spine. (B,D,F) Time course of PAGFP fluorescence in photoactivated (PA) and neighboring spines (n = 6, 6, and 7 dendrites for WT, S3A, and S3E, respectively). (G,H) Fluorescence intensities of PAGFP-cofilin at 10 s (G) or 15–30 min (H) after photoactivation. Ten seconds after terminating PA, the fluorescence intensity was lower in dendrites expressing S3E (25% ± 6.1%) than in WT- (85% ± 22%, p < 0.01) and S3A-expressing dendrites- (74% ± 21%, p < 0.01). In contrast, at 15–30 min, no differences were observed (2.6% ± 1.1%, 4.3% ± 3.4%, and 4.6% ± 3.5% for WT, S3A, and S3E, respectively; p > 0.4). Data represent the mean ± SD. **p < 0.01, using Steel’s multiple comparison test after the Kruskal–Wallis test.