(I am not at my editing system right now, so I am doing this from memory.)
You can probably accomplish it by setting up 3 effects – I’d use an adjustment layer:
Channel Combiner1 set RGB to YUV
Curves Effects
RGB= don’t use
Red = Y
Green = U
Blue = V
Channel Combiner2 set YUV to RGB
Another idea, Synthetic Aperture Color Finesse is a color correction tool that comes with AE. It can manipulate colors using YCbCr notation. which is for most purposes the same as YUV.
Jim
Colorburst Video