Fig. 4. Hsp90 is necessary for G12/Src regulation of permeability and TJ structure. (A) QL12-MDCK cells in +/–dox and +/–GA (2 µM) for 72 hours were analyzed for TER as described in the Materials and Methods. (B) Sodium and chloride permeability were determined in QL12-MDCK cells +/–dox and +/–GA as described in Materials and Methods. (C) Effect of GA in QL12-MDCK cells +/–dox on size selectivity for cation permeability relative to sodium [lithium (Li; 1.2 Å), potassium (K; 2.66 Å), rubidium (Rb; 2.96 Å), cesium (Cs; 3.38 Å) and arginine hydrocholoride (6.96 Å)]. (D) Immunofluorescence microscopy of ZO-1, occludin and claudin 1 in QL12-MDCK cells +/–dox and –dox +GA. Arrow highlights area of membrane thickening. ^*P<0.05. Scale bar: 5 µm.