GFP-tagged α constructs used in this study. (a) Schematic diagram of the two GFP-tagged constructs. (b) Homogenates of control cells and cells stably transfected with the GFP-tagged α construct, either with or without treatment with an siRNA to deplete endogenous α, were subjected to SDS-PAGE and blotted, and the blots were probed with antibodies against αA, αC, or clathrin heavy chain. Endogenous αA and αC disappear upon knockdown; the construct does not.