Depletion of furin from airway smooth muscle tissues increases Akt phosphorylation and decreases smooth muscle myosin heavy chain (SmMHC) expression. A, B: representative immunoblots and mean expression levels of endogenous furin protein in extracts from tissues treated with furin shRNA or sham treated. ShRNA significantly reduced expression of furin (n = 10, P = 0.0001) (A) and SmMHC (n = 9, P = 0.0001) (B). C: the depletion of furin caused a significant increase in eotaxin secretion (n = 4, P = 0.0272). D: representative immunoblots of Akt from extracts of sham-treated or furin-depleted muscle tissues stimulated with IL-13 or unstimulated (US). Furin depletion resulted in a significant increase in Akt phosphorylation at Ser473 (n = 7, P = 0.0001). Furin inhibition also significantly potentiated IL-13-induced Akt phosphorylation (n = 7, P = 0.019). Data were analyzed by using a paired Student’s t test (A–C) or one-way ANOVA (D). Values are means ± SE. *Significant difference between groups.