English: a Simplified scheme of translational repression and activation that the CPEB protein exerts by regulating polyadenylation in Xenopus. Maskin interacts with CPEB and eIF4E, preventing the formation of the initiation complex. After CPEB phosphorylation, PARN dissociates from the complex and PAP initiates elongation of the poly(A) tail. PABP proteins bind to the poly(A) tail, promoting the formation of the initiation complex and dissociation of Maskin from eIF4E. b Optimal localization of binding sites in the 3’UTR of mRNA for translational regulation with the CPEB proteins in vertebrates. CPSF, cleavage and polyadenylation specificity factor. c Primary structure of the CPEB proteins with a prion-like domain at the N-terminus (drawn to scale). Numbers refer to amino acid positions. All CPEB proteins have RNA recognition motifs (RRMs) and a zinc finger domain (ZnF) at the C-terminus. Stretches of amino acids are colored: Q, glutamine rich; PQ, proline/glutamine rich; SA, serine/alanine rich; PA, proline/alanine rich; PAQ, proline/alanine/glutamine rich