Figure 2

Fyn kinase is a mediator of IFNγ-induced decreases in T84 epithelial monolayer barrier function. (a) Increased association of Fyn with immunoprecipitated interferon-γ receptor (IFNγR) 2 subunit 15 min following IFNγ stimulation is shown. Input lysate levels of Fyn protein as well as an absence of immunoprecipitated Fyn from non-immune IgG control incubations are also shown. Densitometric quantification of Fyn immunoprecipitants was performed using Image J. (b) Reduction of Fyn protein demonstrated by immunoblotting in T84 cells treated 96 h previous with Fyn siRNA. (c, d) T84 cell monolayers exposed to IFNγ (10 ng/ml; 48 h) and transfected with an irrelevant scrambled (Cont) siRNA displayed significant increases in translocation of HRP and E. coli (HB101) fluxes that were not apparent in monolayers transfected with Fyn siRNA. In contrast, the drop in transepithelial resistance (TER) that accompanies IFNγ treatment was not inhibited by Fyn knockdown (e). (c–e) Data represented as mean±s.d.; n=3 monolayers/treatment/experiment, representative of four experiments; ^*P<0.05 compared with control (Unstim). ND, not detected.