HeLa cells were grown in 24-well plates on glass coverslips (50,000 cells/well) for 24 hrs. Cells were then transfected (1 mg of DNA with lipofectamine 2000 as described above) with plasmids encoding wild-type or dominant-negative (DN) human MLCK fused to GFP [78] , wild-type or DN Rab5 fused to GFP [79] , or MyoII-tail or MyoII-head domain fused to GFP [80] . 24 hr after transfection cells were inoculated with IAV-WSN (MOI 1) in PBS or in PBS containing 10% FCS and 80 mM dynasore. 4 hr after infection cells were fixed and stained for examination by confocal microscopy as described above.