Western blot analysis of PKC-, βΙ, δ, ɛ, η, and ζ isoforms in homogenates obtained from 32D (A), 32D GM1 (B), 32D G (C), and 32D Epo1 (D) cell lines. Cells were examined before (lane 1) and after 4 hours of serum-starvation (lanes 2 through 5) in the absence (lane 2) or presence of the specific growth factor that was readded for 15 (lane 3), 30 (lane 4), and 60 (lane 5) minutes. The positive control was represented by a rat brain homogenate (lane 6). A representative of five separate experiments is reported.