Fig. 6. Model of the interaction between unfolded actin, PFD and CCT. (A and B) Side view and top views, respectively, of the proposed ternary interaction between actin, PFD and CCT. The PFD:actin complex shown in Figure 5 interacts with specific CCT subunits through the tips of some of the PFD subunits and presents the actin molecule to the CCT subunits that interact with this molecule (Llorca et al., 1999). The actin molecule has been fitted into the actin part of the three-dimensional reconstruction of the CCT:actin complex used to generate the model (Llorca et al., 2000). The color code of the actin molecule is as in Figure 5.