MRC5 SMAD/TGFbeta Reporter (Luc) cells are derived from the human fibroblast cell line MRC5 by stably integration of a SMAD/TGFbeta firefly luciferase reporter construct. MRC5 cells are widely used in the studies of cell biology, virus biology, cellular aging and toxicology. MRC5 SMAD/TGFbeta Reporter (Luc) cells stably express firefly luciferase under the control of the SMAD/TGFbeta response elements, can be used for monitoring the activity of TGF?/SMAD signaling pathway.