C. Immunofluorescence staining

Adherent and non-adherent cells were fixed with a solution of 4% paraformaldehyde in 1X PBS for 15 min and permeabilized with 0.2% Triton X-100 for 20 min. The cells were then blocked with 2% bovine serum albumin (BSA) in 1X PBS (PBS-2% BSA) at room temperature for 1 h, incubated with primary antibodies for paxillin (recombinant anti-paxillin antibody [Y113], Abcam ab32084; 1:250 dilution) and myosin [phospho-myosin light chain 2 (Ser19) antibody, Cell Signaling Technologies^® (# 3671); 1:250 dilution] in PBS-2% BSA for 48 h at 4  °C. The sample was incubated fo0r 48 h at 4  °C for secondary antibodies Alexa Fluor 647 (donkey anti-rabbit, Abcam ab 150075, 1:500 dilution) and Alexa Fluor 555 [anti-mouse IgG (H + L), F(ab ′)2 fragment, 1:500 dilution]. Phalloidin staining was performed with Alexa Fluor 488 phalloidin (Life Technologies; 1:200) diluted in PBS with 2% BSA for 48 h at 4°C. Images were taken with 2X (air), 40X, and 60X oil immersion objective. Analysis was performed with ImageJ and Imaris (Bitplane).