RAPH1 and breast cancer: Depletion of Lpd in MDA-MB-231 breast cancer cells decreased lamellipodia size (Supplementary Figure 3A), similar to B16-F1 mouse melanoma cells, in which Lpd depletion also reduces protrusion speed under steady-state conditions.17 EGF-stimulated MDA-MB-231 Lpd knockdown cells displayed reduced protrusion persistence and distance, without affecting protrusion speed (Supplementary Figure 3B).