FIG. 8.

Proposed model of 4GH domain-mediated transcript destabilization. Stable, efficiently translated transcripts are believed to adopt a closed-loop conformation mediated by protein-protein interactions which bridge the 5′ cap (m7G) and the 3′ poly(A) tail. The model suggests that the 4GH domains of rent2 and NAT1 may compete with the corresponding domain in eIF4G (and perhaps PAIP-1) for interacting partners eIF3 and/or eFI4A. Such associations (dashed lines) may occur in cis when rent2 is a component of a mature surveillance complex (partnered with rent1 and rent3) but in trans upon induction of NAT1 expression.