Figure 3.

A pictorial representation of the proposed CSC retrieval subdomain on the endosomal surface (based on data from Jia et al. 2012). The CSC is associated with the cytosolic face of the early endosome and the maturing late endosome through association with the phosphatidylinositol 3-monophosphate (PI3P)-binding SNX3 and Rab7-GTP, respectively. In addition to cargo selection mediated by the CSC, associated adaptors also engage cargo (the PI3P-binding SNX27 is depicted). Through association of the unstructured tail of FAM21, multiple CSCs, along with their associated cargoes, become enriched into a retrieval subdomain (retrieval zone) in which lateral mobility is restricted as a result of WASH-mediated actin polymerization. In the lower bird’s-eye view, two associated CSCs are shown to reflect evidence for dimeric assemblies (Norwood et al. 2011).