Fig. 3.
Nuclear accumulation of GHR in vitro is mediated by a classical nuclear import pathway involving Impα and -β. (a) CLSM visualization showing localization of T-Ag-GFP (Upper) and GHBPC (GHBPC-IAF) (Lower) in mechanically perforated HTC rat hepatoma cells in the absence or presence of cytosol or cytosol with anti-IMPβ antibody. (b) Quantitative measurements of the kinetics of nuclear accumulation of GHBPC (Left) and T-Ag-GFP (Right), +/− exogenous cytosol in the absence or presence of specific antibodies to IMPα or IMPβ. [Data were fitted for the function Fn/c(t) = Fn/cmax × (1− e-kt], where t is time, Fn/cmax is the maximal level of nuclear accumulation, and k is the first-order rate constant. (c) Recognition of GHBPC by the IMP α/β heterodimer as indicated by native gel electrophoresis imaging; 25 pmol GHBPC-IAF or T-Ag-GFP was incubated in the absence or presence of 10 μM IMPα/β heterodimer for 15 min at 20°C, before electrophoresis.