Figure 4.
Shear stress–mediated structural reorganization of the KIF network requires K18pSer33-A549 cells were transiently transfected with GFP-tagged K18 wild-type (A–D) or GFP-tagged K18 S33A mutant (E–H). The wild-type and mutant cells were exposed to shear stress (30 dyn/cm2; 60 min) fixed, and processed for indirect immunofluorescence using anti-K18 and direct immunofluorescence for GFP. In GFP-K18S33A and GFP-K18 cells exposed to shear stress for 60 min, the endogenous keratin IF network (red channel) was thick and wavy and formed tonofibrils (C and G). In the GFP-K18S33A cells the exogenously expressed keratin IF network (green channel) was disassembled/degraded after exposure to shear stress (H). In the GFP-K18 cells the exogenously expressed GFP-keratin IF network was intact (D).