Cortical localization of DDR1 in cells expressing E-cadherin prevents efficient centrosome clustering. (A) Immunofluorescence images showing cortical localization of DDR1 during mitosis. Cells were stained for F-actin (phalloidin, red), DDR1 (green), and DNA (blue). White arrows represent areas where there are no cell–cell contacts. (B, left) Western blot analysis of DDR1 and E-cadherin levels after siRNA depletion of DDR1 in MCF10A cells. (Right) Quantification of centrosome clustering in cytokinesis upon DDR1 depletion. (C, left) Western blot analysis of DDR1 and E-cadherin levels after siRNA depletion DDR1 in HaCaT cells. (Right) Quantification of centrosome clustering in cytokinesis upon DDR1 depletion. (D) Western blot analysis of the levels of E-cadherin and DDR1 in RPE-1 cells expressing exogenous WT E-cadherin and E-cadherin DN. (E) Quantification of centrosome clustering in cytokinesis in RPE-1 cells expressing E-cadherin and E-cadherin DN before and after DDR1 depletion by siRNA (n = 150). (F) Quantification of centrosome clustering in metaphase and cytokinesis in MCF10A cells treated with 15 µM DDR1 inhibitor for 3 h. (G) Western blot analysis of RhoE levels in HaCaT cells after siRNA depletion of RhoE. (H) Quantification of centrosome clustering in cytokinesis upon RhoE depletion (n = 150). (I) Schematic representation of RhoE-mediated regulation of cortical contractility downstream of E-cadherin. For all graphics, error bars represent mean ± SD from three independent experiments. ***, P < 0.001; ns, not significant. Bar, 10 µM.