Fig. 2. SGs show discrete microdomains and dynamic shuttling of some components. (A) SGs are positive for MLN51, TIA1 and FMRP. Arsenite-treated HeLa cells, were fixed and co-labelled with anti-MLN51 (a, purple), anti-TIA1 (c, red) and anti-FMRP (b, green) antibodies. Nuclei were counterstained with Hoechst (d, blue) and the merged image of a, b and c is shown in e. (B) Confocal analysis of MLN51 and FMRP distribution into SGs. Arsenite-treated cells were co-labelled using anti-MLN51 (green) and anti-FMRP (red) antibodies and with Hoechst (blue). One section of 200 nm of the merge image is shown; inserts on the top left and lower right inside are higher magnification (2.5 fold) images of the SGs present in dotted squares. (C) FRAP analysis of MLN51Fl and MLN51Ct mobilization into SGs after arsenite treatment. HeLa cells transfected with EYFP-tagged MLN51 full length (fl) and MLN51/377-703 (Ct) and GFP-tagged hnRNPA1 and PABP for 48 hours and treated with arsenite were analysed by FRAP. One representative cell expressing EYFP-MLN51Fl (a) or EYFP-MLN51Ct (b) is shown. In both cases one granule (square boxes) was bleached and pictures were taken every 3 seconds. Time is indicated in seconds on each picture. (c) Graphical representation of fluorescence recovery patterns. Curves represent fluorescence intensity over time (seconds) and each curve corresponds to ten independent experiments.