FIGURE 5.

Cartoon representation of the Dcp1:Dcp2 decapping complex and the interactions with Xrn1, Pat1, or Dhh1 (A), the Dcp2 C-terminal region (B), and Edc1 and substrate RNA (C). The EVH1 fold in the Dcp1 protein is colored yellow, the Dcp2 regulatory domain light green, and the Dcp2 catalytic domain dark green. (A) The adapter proteins Xrn1, Pat1, and Dhh1 can be recruited by Dcp1. (B) The C-terminal region of Dcp2 contains multiple PRS that interact with Dcp1 in a structurally similar manner as the adapter proteins do. (C) The activator protein Edc1 interacts with Dcp1 and the regulatory domain of Dcp2. Edc1 increases the binding affinity for capped RNA, suggesting that Edc1 contacts the substrate. The interactions displayed in A and B compete with the recruitment of the activator Edc1 or PNRC2 to the decapping complex.