Figure 6.

Ca²⁺-dependent MLC activation enhances filopodia formation via p-cortactin rearrangement. (A) Representative immunofluorescence (IF) images of MKN-45 and DLD-1 cells stained for mitochondria and F-actin (red: mitochondria, green: F-actin). Scale bar: 10 μm. (B) Representative MYO10 IF staining in MKN-45 and DLD-1 cells treated with CCCP (10 μM) (blue: nuclei, red: MYO10, green: F-actin). Scale bar: 20 μm. (C) Quantification of MYO10-positive filopodia in MKN-45 and DLD-1 cells treated with CCCP (10 μM). Data are expressed as means ± SD, **P < 0.01, ***P < 0.001 (vs. DMSO group). (D) Representative IF staining of MKN-45 and DLD-1 cells (blue: nuclei, red: dil, green: MYO10, violet: p-cortactin). Scale bar: 20 μm (left). Zoomed-in images and fluorescence co-localization of p-cortactin and MYO10 at filopodia tips in MKN-45 and DLD-1 cells (MKN-45: Pearson > 0.9; DLD-1: Pearson > 0.9). Scale bar: 2 μm (right). (E) Quantification of p-cortactin-positive filopodia tips per cell in MKN-45 and DLD-1 cells treated with CaCl₂ (5 mM) or BAPTA-AM (10 μM). Data are expressed as means ± SD, *P < 0.05, **P < 0.01 (vs. DMSO group). (F) Quantification of p-cortactin-positive filopodia tips per cell in MKN-45 and DLD-1 cells treated with calyculin A (50 nM) or P18 (8 μM). Data are expressed as means ± SD, *P < 0.05, **P < 0.01, ***P < 0.001 (vs. DMSO group). (G) Representative MYO10 IF staining in MKN-45 and DLD-1 cells treated with PP2 (10 μM) (blue: nuclei, red: MYO10, green: F-actin). Scale bar: 20 μm. (H) Quantification of MYO10-positive filopodia in MKN-45 and DLD-1 cells treated with PP2 (10 μM). Data are expressed as means ± SD, *P < 0.05, **P < 0.01 (vs. DMSO group).