Fig. 6. Cell-surface ADAM12 induces actin cytoskeleton reorganization in 3T3-L1 cells. (A-C) 3T3-L1 cells were analyzed by staining with rhodamine-conjugated phalloidin to monitor F-actin organization during differentiation. (D-L) Growing 3T3-L1 cells were transfected with plasmids encoding ADAM12-cyt/EGFP (D-F), ADAM12-cyt catalytic site mutation/EGFP (G-I) or vector control (J-L) and analyzed for EGFP (D,G,J), F-actin (E,H,K) and by phase-contrast microscopy (F,I,L). Cytoskeletal organization was disrupted in cells transfected with either ADAM12-cyt or ADAM12-cyt with a catalytic site mutation (E,H), whereas actin stress fibers were maintained in cells transfected with the vector control (K). Single and double arrows indicate actin stress fibers and cortical actin, respectively. Bars, 10 µm (A-C) and 7 µm (D-L).