Knockdown of 14-3-3 β/α isoform in NCI-H441 cell line and correlation with SP-A2 expression. Six different shRNAs (1–6), plus another 2 (not shown), were used to knock down the expression of 14-3-3 β/α isoform by RNA interference. A scrambled shRNA (negative control) that does not target any human, mouse, or rat gene was used as control. Western immunoblot was employed to monitor the expression of 14-3-3 β/α isoform (28 kDa), SP-A2 (35 kDa), SP-A1 (35 kDa), 14-3-3 τ/θ isoform (28 kDa), and actin (42 kDa). The experimental shRNAs inhibited the 14-3-3 β/α isoform to a varying degree and this correlated with levels of SP-A2. No differences were observed for SP-A1 and 14-3-3 τ/θ; actin was used as internal control.