Figure 3: Podosome protrusive force depends on actomyosin contractility.

(a) Means±s.e.m. of podosome protrusion heights on 30 nm-thick Formvar sheets in control conditions or after blebbistatin addition are shown. t-test was used to compare protrusive heights generated by at least 200 protrusions from five donors. ***P<0.001. (b) Means±s.e.m. of podosome protrusive forces in control conditions or after blebbistatin addition are shown. t-test was used to compare protrusive forces generated by at least 100 protrusions from three donors. ***P<0.001. (c) Representative immunoblottings using antibodies directed against myosin II and αTubulin (αTub) on cell lysates from macrophages transfected with control siRNAs or siRNAs targeting myosin II. (d) Means±s.e.m. of relative myosin II levels normalized on αTubulin immunoblot signals used as a loading control are shown. Mann–Whitney U-test (P<0.01) was used to compare relative myosin II signals in macrophages from five donors treated with indicated siRNAs. (e) Means±s.e.m. of podosome protrusion heights in control conditions or after myosin II depletion by siRNA are shown. t-test was used to compare at least 250 podosome protrusive heights generated by macrophages from five donors. ***P<0.001. (f) Means±s.e.m. of podosome protrusive forces in control conditions or after myosin II depletion by siRNA are shown. Statistical analyses were performed by t-test. 120 protrusions from three donors were measured. ***P<0.001. (g) Means±s.e.m. of protrusion heights under control conditions or after addition of ML7+Y27632 or CD are shown. t-test was used to compare at least 150 podosome protrusions in cells obtained from at least three donors. ***P<0.001. (h) Means±s.e.m. of podosome protrusive forces in control conditions or after addition of ML7+Y27632 or CD are shown. t-test and Dunnett’s multiple comparison test were used to compare at least 16 podosome protrusive forces in cells obtained from at least four donors. ***P<0.001.