Model of proposed role of Hsc70 in cargo sorting. Hsc70 ATPase and its adaptor Auxilin could mediate the turnover of clathrin on the growing CCPs. In the absence of such clathrin turnover, cargo-bound and cargo-free coat components are not discriminated; coat assembly proceeds without enriching cargo. K_n/K_n' and K_-n are forward and reverse rate constants, respectively.