Figure 2.

Calpain 2 is required for ECM degradation and invasion. (A) MTLn3 cells expressing control or calpain 2 siRNA were cultured on Oregon green 488 gelatin–coated coverslips and stained with anti-cortactin antibody. Arrows indicate areas of degradation that colocalize with cortactin containing invadopodia. Quantification of the percentage of cells containing any ECM-degrading invadopodia is shown. Data are mean ± SEM of three independent experiments. *, P < 0.02 compared with control cells. (B) MTLn3 cells expressing control or calpain 2si were plated on Matrigel-coated membranes and assayed for their ability to invade through the membrane. Invasion is shown relative to control cells. Data are mean ± SEM of three independent experiments. *, P < 0.04 compared with control cells. Bars: (A) 10 μm; (B) 1mm.