Figure 3.

The Atypical ESCRT-III Protein IST1 Accumulates on Endosomes in Proband Fibroblasts

(A) Cultured fibroblasts from control subjects or the probands indicated were fixed, labeled against EEA1 and IST1, then visualized with confocal immunofluorescence microscopy. The number of IST1 puncta per cell and the percentage of EEA1-positive endosomes associated with an IST1 punctum was quantified in three such experiments (in five cells per experimental condition in each biological repeat) and plotted in the corresponding charts. Arrows indicate juxtaposed or co-localized puncta.

(B) Cultured fibroblasts from control subjects or the probands indicated were fixed and labeled for the endosomal tubular marker SNX1, then visualized with widefield immunofluorescence microscopy. The percentage of cells with at least one SNX-1-positive tubular structure > 1.2 μm in length was quantified in 100 cells per sample, and the results for three such experiments were plotted in the corresponding chart. Bars indicate mean ± SEM, p values calculated by one-way ANOVA with Tukey’s post hoc test for repeated-measures. Micrograph scale bars = 10 μm.