Arg L207R/T233S-EYFP is unable to rescue cell edge protrusion in fibroblasts adhering to fibronectin.
A–D, phase images and 10-min kymographs of wild type fibroblasts (A) and arg−/− fibroblasts expressing EYFP (B), wild type Arg-EYFP (C), or Arg L207R/T233S-EYFP (D). Scale bars indicate 10 μm. Quantification of protrusions (E) and retractions (F) were measured over 10 min. Values are mean ± S.E., ****, p < 0.0001. G, phosphorylation levels of cortactin in arg−/− fibroblasts expressing EYFP, Arg-EYFP, or Arg L207R/T233S-EYFP. Cortactin was immunoprecipitated (IP) and Western blotted for phosphotyrosine. Cortactin phosphorylation is reduced in arg−/− + EYFP fibroblasts, but similar in arg−/− + Arg-EYFP and arg−/− + Arg L207R/T233S-EYFP cells. H, quantification of cell spreading. Cell area was measured at 0, 10, 20, and 30 min of spreading on fibronectin.