αCat forced dimerization promotes cortical recruitment and filopodia formation. Part 1: live imaging of mCherry-iDimerize Empty-Vector (EV) and mCherry-iDimerize-ΔNαCat-expressing R2/7 DLD1 cells treated with (+) or without (−) bidentate (B/B “dimerizer”) and monodentate washout (W/O) ligand in 6-h time course. Note that labels and time stamps are incorporated within corresponding image frames. mCherry-iDimerize-ΔNαCat is rapidly recruited to the periphery after addition of B/B ligand (within 10 s; red arrows). The mCherry-iDimerize EV (control construct) localizes to the nucleus and cytoplasm, where addition of the B/B ligand promotes nuclear exclusion rather than cortical recruitment. Part 2: live imaging of mCherry-iDimerize- WT-ΔNαCat– and ΔNαCatKKR<3A mutant–expressing cells (red) coinfected with GFP-LifeAct (green). Shown first: mCherry-iDimerize-WT-ΔNαCat before (left) and after (right) B/B treatment (40-s time course). Note formation of elongated filopodia within 10 s after B/B treatment. Shown second: mCherry-iDimerize- ΔNαCatKKR<3A mutant expressing cell before (left) and after (right) B/B treatment (60-s time course). Note no formation of elongated filopodia after B/B treatment.
