Figure 2
Tyrosine phosphorylation of MT1-MMP control cortactin recruitment on MT1-MMP endosomes.
(A) Expression of MT1-MMPmCh mutants in MDA-MB-231 cells (B) MT1-MMPmCh WT, Y573F and Y573E were overexpressed in MDA-MB-231 cells during 24 hours. Cells were plated on gelatin and immunolabelled with antibody against cortactin (in green). Z-projection. Scale bars, 5 μm (entire cell); 1 μm (boxed region at higher magnification). (C) Quantification of cortactin on MT1-MMPmCh endosomes in MDA-MD-231 cells. The y-axis indicates mean cortactin intensity associated with MT1-MMPmCh-containing endosomes normalized to the value in control MT1-MMPmCh WT cells (in percentage) ± SEM (n is the number of cells analyzed, from at least 3 independent experiments). ***P < 0.001. (D) MDA-MB-231 cells were treated with indicated siRNAs (siNT, for non-targeting siRNA), plated on gelatin and stained with antibodies against cortactin (in red) and Rab7 (in green). Z-projection. Scale bars, 5 μm (entire cell); 1 μm (boxed region at higher magnification). (E) Quantification of cortactin on Rab7 vesicles in MDA-MD-231 cells. The y-axis indicates mean cortactin intensity associated with Rab7-containing endosomes normalized to the value in control siNt-treated cells (in percentage) ± SEM (n is the number of cells analyzed, from at least 3 independent experiments). *P < 0.05.
