Fig. 4.

Cell-ECM adhesions are required for LIPUS-induced CDR formation and increases in early endosomes. (A,B) Cells were seeded on fibronectin or Cell-Tak coated glass and stained for actin and the FA marker paxillin. Cells on fibronectin form FAs (yellow arrowheads), connected to actin stress fibres (red arrowheads), whereas the majority of cells on Cell-Tak did not form any adhesions. In some cases, cells on Cell-Tak were able to form adhesions. Scale bar: 20 µm. (C) LIPUS stimulation of cells on fibronectin (FN) produced an increase in the number of cells with CDRs, but LIPUS stimulation had no effect on CDR formation in cells on Cell-Tak, including those that had formed some small adhesions. (D) Control and LIPUS-treated cells on either fibronectin or Cell-Tak and stained for paxillin and EEA1 (colour inverted). Scale bar: 10 µm. (E) Quantification of the number of early endosomes in LIPUS-stimulated and control cells on FN- or Cell-Tak-coated glass. Note that LIPUS-stimulation had no effect on the number of early endosomes in the cells on Cell-Tak. Data in C and E are from three independent experiments and are presented as described in the Materials and Methods; n numbers are indicated below the plots. **P<0.01, ***P<0.001.