Marked reduction in the endosomal and nuclear localization of pSmad1 in Bmpr1aCKOlenses. A. WT (Cre-negative) lens; Rab5B (green), pSmad1 (red). B. Bmpr1aCKO(Cre-positive) lens Rab5B (green), pSmad1 (red). Both the number of endosomes and the relative number of Smad1-positive endosomes is reduced in the Bmpr1aCKOlens. In B, note the relative difference in staining intensity for pSmad1 and Rab5b in the ciliary epithelium (CE), compared to the Bmpr1aCKOlens.