Figure 5

Schematic models for cargo selection and Cvt vesicle formation. The Cvt pathway selectively transports the vacuolar hydrolases aminopeptidase I (Ape1) and α-mannosidase (Ams1) into the yeast vacuole. Precursor Ape1 (prApe1) is synthesized in the cytosol, forms dodecamers, and is further assembled into an Ape1 complex composed of multiple dodecamers. The propeptide region of prApe1 is recognized by its receptor Cvt19, which independently recruits Ams1. This process is termed the cargo selection step for the Cvt pathway. Cvt9 subsequently binds to the complete Cvt complex (Cvt19 bound to cargo) and mediates the tethering step of the Cvt pathway. When the Cvt complex reaches its destination, the perivacuolar preautophagosomal structure (PAS), Cvt19 further interacts with Aut7 accompanied by the release of Cvt9. The Cvt19-Aut7 interaction ensures that the cargo proteins are packaged inside the forming Cvt vesicle.