Fig. 8. A model illustrating Syt III function in endosomal trafficking. According to this model, in control cells (A) Syt III regulates the formation of the endocytic recycling compartment (ERC) and the delivery to this compartment from the early endosome (EE) and the immature granule (ISG) during the process of granule maturation. In the RBL-Syt III^- cells (B), suppression of Syt III inhibits the formation of and delivery to ERC from both the EE and the ISG.