SMURF1 knockdown reactivates BMP signaling in SDCs. (A) SMURF1 knockdown screening by qRT-PCR in lentivirus transduced cells expressing negative knockdown shRNA control (shNeg) or one of three different shRNA constructs (shSMURF1-173, −724, and −332) targeting SMURF1 transcripts for silencing. Expression levels are relative to non-transduced parental control cells. Expression was normalized to the GAPDH housekeeping gene and presented as mean ± SD. Screening was performed in monolayer cells in duplicate. (B) SMURF1 immunoblotting in SDCs expressing shSMURF1-724 shRNA gene silencing construct relative to shNeg and parental controls from two cell lines. (C) Immunoblotting of pSMAD1/5/8 in SDCs from two cell lines expressing shSMURF1-724 shRNA gene silencing construct relative to shNeg, parental, and monolayer cells. β-actin was used for a gel loading control. Data shown are representative of at least three independent experiments.