Model of CPEB-mediated translational control. A CPE-containing RNA is recognized by a CPEB and Maskin-containing protein complex in the nucleus either co-transcriptionally or soon after transcription is complete. After export from the nucleus, a cytoplasmic RNP complex is assembled that includes the poly(A) polymerase Gld2 and the deadenylating enzyme PARN. PARN is expelled from the complex upon progesterone-induced and aurora A-catalyzed CPEB phosphorylation; Gld2 then elongates the poly(A) tail by default. Maskin is phosphorylated at this time. These events, as well as its association with an embryonic poly(A) binding protein (not shown), lead to the replacement of Maskin for eIF4G on eIF4E. As a consequence, translation is activated. The association of eIF4A3 with the cytoplasmic complex is conjectural.
