To investigate whether the quantities of TGF-β1 and BMP-2 released from bone chips within different time periods are sufficient to activate TGF-β and BMP signaling, respectively, we analyzed the phosphorylation of TGF-β1- and BMP-2-specific receptor-regulated Smad proteins (R-Smads) in BCM-treated ST2 cells (Fig. 1c, d). This evidence concerns the gene BMP2 and blue cone monochromacy.