Fig. 8. Proposed model. Dab2 binds to clathrin, PtdIns(4,5)P₂ (PIP₂), LDLR, MyoVI and accessory proteins, independently of AP-2 (left), and actively mediates LDLR movement to, or trapping in, coated pits (step 1), where it recruits clathrin and completes budding (steps 2,3). By contrast, ARH binds clathrin, PtdIns(4,5)P₂ and LDLR but only recruits accessory proteins indirectly via AP-2 (right). Recruitment of LDLR to coated pits by ARH may be by passive diffusion (step 4). As clathrin assembles, it may displace ARH from AP-2 and LDLRs may remain trapped without a specific adaptor (steps 5,6). See text for explanation and evidence.