Furthermore, we over-expressed Thr49 mutation BMPR1A, Thr137 mutation BMPR1A, or wild BMPR1A in PCa cells, and found that p-Smad1/5/9 levels in T49A and T137A cells were both increased compared to that in control cells, but still lower than that in cells over-expressing wild BMPR1A (Fig. 5I). Here, SMAD1 is linked to posterior cortical atrophy.