And while this did help reliability, the AP2 never had the same high-revving flair that made the AP1 so cool. That wasn't all: one major painpoint of the AP1 was the overly hard suspension ...

Clathrin that is associated with AP1 and AP3 forms vesicles for transport ... Clathrin that is associated with AP2 forms vesicles from the plasma membrane that transport to the early endosomes.