Translocation of PKCα induced by PAF and its inhibition by Ro 31-8220. HEC-1B cells were incubated in the absence of serum for 24 hr prior to stimulation with 1 nM PAF either alone (A) or in the presence of the PKC inhibitor, Ro 31–8220 (B) for the times indicated. Cells incubated with PAF in the presence of 10 µM Ro 31–8220 were pretreated for 30 minutes prior to stimulation. Cytosolic and particulate fractions were prepared and analyzed by Western immunoblot analysis with PKC alpha antibody. Top panel: Western blot shows the location of the alpha isozyme in resting confluent cells, its association with the membrane following PAF addition (A), and inhibition of this association in the presence of Ro 31-8220 (B). Bottom panels of (A) and (B): Corresponding densitometric analysis. Presented are the results of a typical experiment (n = 4).