(A) Model: The WASP/Myosin complex has four activities that are necessary for CME and sufficient for a functional WASP/Myosin complex.
(B) Theoretical outward-directed movement of individual, growing actin filaments that are tethered to the bud tip but not the base.
(C) Model: The TH1 and motor domains constitute a membrane-actin linkage that tethers F-actin to the base of endocytic sites. While the F-actin at endocytic sites is a branched, cross-linked network, we have shown only two individual filaments for clarity of presentation. See also Movie S5.