FIG. 8.

Hypothetical default pathways in trypanosomes. Known pathways between endomembrane compartments, including the early endosome (EE), recycling endosome (RE), and late endosome (LE), are indicated by black arrows. The numbers indicate sites where clathrin-coated vesicles are known to operate, including the flagellar pocket (no. 1) (2), the recycling endosome (no. 2) (21), and the Golgi apparatus (no. 3) (this work). Our work indicates that AP-1 functions at site no. 3 of clathrin-mediated trafficking in PCF cells, and possibly also in BSF cells, but not at site no. 1. No information is available for site no. 2. The question mark in the Golgi apparatus-to-flagellar pocket pathway indicates uncertainty as to whether this is a direct route or indirect via the endocytic pathway. The proposed BSF default pathway to the lysosome is indicated in red. The proposed default PCF pathway to the cell surface is in blue and essentially follows the normal pathway to the flagellar pocket.