Fig 5. Knock-down of SMA expression increases the activation of Rac.

SMCs were transfected with non-specific, GC-matched siRNA (control) or siRNA targeting SMA (SMA). (A) Expression of SMA was determined by qPCR measurements and normalized to GAPDH expression. Data (mean + S.D.) from 8 independent transfection experiments are shown. Insert: Western blot analysis of SMA protein expression. The blot was reprobed with beta-actin antibody as a loading control. (B, C) Quiescent controls or cells transfected with SMA-siRNA were stimulated with 10% FBS for 1 and 5 min. Cell lysates were prepared and the amount of GTP-bound Rac (B) and RhoA (C) determined by ELISA following the manufacturer’s instructions. Assays were performed in triplicates with two independent cell batches for each condition. Data (OD490 measurements) are presented as mean +/- S.D. *P<0.001, n.s. = non-significant.