Protein expression of different PKC isoforms in CD34⁺ progenitor cells cultured with different cytokines.

CD34⁺ cells were cultured in vitro for 4 days in medium alone or in the presence of EPO (5 U/mL) and SCF (50 ng/mL), G-CSF (50 ng/mL) and SCF (50 ng/mL), EPO (5 U/mL), or SCF (50 ng/mL) before the preparation of cytosolic proteins. Relative protein expressions of PKC-α, PKC-β2, PKC-γ, PKC-δ, PKC-ε, PKC-ζ, and Bax were determined by Western blotting. (A) One representative blot is shown. Note that for BT4c and U87GM, the upper band for PKC-α is possibly a phosphorylated form. (B) Optical density of PKC-α, determined by densitometric imaging of hyperfilms, is shown. Mean ± SEM of 5 to 12 separate experiments (*P < .001, n = 12;P = .009, n = 5). The expected 80-kd band is used for quantitation. (C) Optical density of PKC-β2, determined by densitometric imaging of hyperfilms, is shown. Mean ± SEM of 5 to 8 separate experiments (*P = .046, n = 5).