Figure 6.

Src kinase activity is essential to rescue dynamic podosome properties in Src^−/− OCLs. GFP-actin was comicroinjected into Src^−/− OCLs with the indicated Src mutant. The life spans of an average of 500 podosomes per condition in 6–9 cells from two to four independent experiments were determined. Expression of Src^WT, Src^Y527F, Src^R175L, or Src^W118K restored podosome life span to values comparable to those of podosomes observed in Src^+/− OCLs. Src^W118K/R175L did not affect life span of podosomes in Src^−/− OCLs. In contrast, expression of Src kinase-dead mutants induced formation of long-lived podosomes, with an average life span greater than 25 min (*p < 0.001 relative to Src^+/−; #p < 0.001 relative to Src^−/−).