Figure 4. Triple labeling of MKN1 cells reveals sequential rearrangement of cytoskeletal filaments in response to EGF.
MKN1 cells were co-transfected with expression constructs for mRFP-actin (A, A’, A”), EB3-CFP (B, B’, B”) and HK18-YFP (C, C’, C”) and were imaged before and after addition of 30 ng/ml EGF. Note that EGF-induced cell extensions are positive for actin and only later recruit microtubules (black arrows). These areas are still negative for keratin after 6 min of EGF treatment. Note also the co-alignment of actin bundles with microtubules (white arrows). A time-lapse sequence of the same cell beginning 10 min after EGF addition is provided as Video S5. Bar, 10 µm.