(A) Increased phosphorylation (shown in duplicate lanes) of Raf-1 (p-Raf-1), ERK1/2 MAPK (p-ERK1/2), Raf-1 kinase inhibitor protein (RKIP) (p-RKIP) and atypical protein kinase Cζ (PKCζ) (p-PKCζ) in hypoxic CCL39 cells stimulated by 5-HT (1 µM; 5 min) which, except for p-PKCζ, was potentiated by the RKIP inhibitor locostatin (5 µM; added 45 min prior to the addition of 5-HT). (B–E) Quantification of data is also shown representing four independent experiments with comparable outcomes [samples were adjusted for loading errors, using the tubulin blot density to standardize, prior to normalization relative to control (unstimulated) values]. Quantitative data are shown as mean ± SEM. *P < 0.05, significantly greater than normoxic control (unstimulated) value. †P < 0.05, ††P < 0.01, †††P < 0.001, significantly greater than hypoxic control value. ‡P < 0.05, ‡‡P < 0.01, significantly greater than 5-HT-treated cells.