Fig. 8. A model illustrating TPA-induced trafficking of PKC in RBL cells (A) and RBL-Syt II^- cells (B). According to this model, exposure to TPA of the control cells results in translocation of PKC from the cytosol to the plasma membrane, from where the enzyme is delivered to early endosomes and subsequently a fraction is delivered to the SG, whereas most of the kinase is delivered to late endosomes and degradation. In the RBL-Syt II^- cells, the transport to the late endosome and the degradative compartment is retarded because of the reduced amount of Syt II. As a consequence, the kinase is delivered to the recycling endosomal compartment, from where it recycles back to the plasma membrane. EE, early endosomes; RE, recycling endosomes, LE, late endosomes; SG, secretory granules; N, nucleus.