Fig. 5. p130^CAS and Paxillin are dephosphorylated in upstream focal adhesions in response to flow. (A) Sparse PAECs were exposed to shear flow for five minutes (arrow, 20 dyn/cm²), and then immediately fixed and double stained for paxillin, p130^CAS and FAK (left column) and the corresponding phosphorylated forms, namely, pY118, pY165 and pY397, respectively (middle column). Ratio images (right column) highlight the relative levels of the phosphorylated proteins compared to total protein. Images of p130^CAS and FAK under no flow conditions can be seen in supplementary material Fig. S2. (B) Quantification of the average intensity of total and phosphorylated forms of paxillin, p130^CAS and FAK in upstream and downstream focal adhesions was calculated for more than a thousand focal adhesions from 20 different cells, under no flow conditions or after 15 minutes of flow. The average intensity after 15 minutes of flow, normalized by the intensity under no flow conditions, is presented. Bars indicate s.e.m. Bar, 5 µm.