Fig. 8.

Phosphorylation of T544 controls apical actin recruitment and dynamics. (A) Lumen morphology and distribution of mCherry::ACT-5 in the excretory canal of L4 larvae. Canal widths vary (see Fig. 3E), and examples of severely widened and less severely widened canals are shown. Graph shows apical-to-cytoplasmic ratio of mean intensity of mCherry::ACT-5. Each data point represents the average of three measurements in a single animal (n=15, 9 and 14). Error bars are the mean±s.d. (B,C) Intestinal distribution of YFP::ACT-5. Arrows indicate discontinuities. Arrowheads in comma stage indicate basolateral YFP::ACT-5, and arrowheads in 2.5-fold stage indicate ectopic expansions of the cortical actin network. (D) Quantification of YFP::ACT-5 levels at the intestinal apical membrane. Each symbol represents a single animal (n=23, 26 and 19 for L1 and n=24, 21 and 22 for L4). Error bars are the median±95% CI. Tests of significance: Dunnett's T3 multiple comparisons test for A; Dunn's multiple comparisons test for D. ns, not significant. **P≤0.01, ***P≤0.001, ****P≤0.0001. Statistical comparisons are with control unless indicated otherwise. (E) FRAP curves of apical mCherry::ACT-5 in the excretory canal of L4 larvae (n=14 for control, n=6 for erm-1[T544A] and n=7 for erm-1[T544D]) and apical YFP::ACT-5 in the intestine of L1 larvae (n=8 for control, n=13 for erm-1[T544A] and n=8 for erm-1[T544D]). Thin lines and shading represent the mean±s.d., and thick lines were obtained by curve fitting averaged FRAP data with a double exponential equation.