FIG. 7.

Effects of Dyn2 tyrosine phosphomutants on Tf uptake in cells depleted of Dyn2. (a to b′) Clone 9 cells depleted of Dyn2 via siRNA and transfected to reexpress WT Dyn2 (a) or a Dyn2 tyrosine point mutant (Dyn2 Y231+597F [b]) were allowed to internalize Alexa-594-labeled Tf at 37°C for 20 min (a′ and b′). Dyn2 was stained (a and b) to detect the reexpressed WT or mutant (*) and analyzed by fluorescence microscopy. (c) WB analysis confirmed that Dyn2 protein levels were reduced by siRNA treatment by 90%. (d) Quantitation of Tf uptake based on fluorescence intensity measurements in control Clone 9 cells and Dyn2 siRNA-treated cells alone or following reexpression of the indicated constructs shows that Dyn2 tyrosine phosphomutants are unable to rescue Tf uptake in cells depleted of endogenous Dyn2. Data are presented as means ± SE. Bar = 10 μm.