Phosphorylation of CPEB by Eg2 mediates the recruitment of CPSF into an active cytoplasmic polyadenylation complex

• Published in: Molecular cell 2000-11, Vol.6 (5), p.1253-1259
• Main Authors: Mendez, R, Murthy, K G, Ryan, K, Manley, J L, Richter, J D
• Format: Article
• Language: English
• Subjects: Animals; Aurora Kinases; Base Sequence; Cell Cycle Proteins; Cell Nucleus - metabolism; CPEB protein; CPSF protein; Cytoplasmic Structures - chemistry; Cytoplasmic Structures - metabolism; Eg2 protein; Macromolecular Substances; Molecular Weight; mRNA Cleavage and Polyadenylation Factors; Oocytes - cytology; Oocytes - metabolism; Phosphorylation; Polyadenylation; Precipitin Tests; Protein Binding; Protein Kinases - metabolism; Protein Subunits; Protein Transport; Protein-Serine-Threonine Kinases; RNA-Binding Proteins - chemistry; RNA-Binding Proteins - metabolism; Thermodynamics; Transcription Factors - chemistry; Transcription Factors - metabolism; Xenopus; Xenopus laevis - metabolism; Xenopus Proteins
• ISSN: 1097-2765
• DOI: 10.1016/S1097-2765(00)00121-0

The release of Xenopus oocytes from prophase I arrest is largely driven by the cytoplasmic polyadenylation-induced translation of dormant maternal mRNAs. Two cis elements, the CPE and the hexanucleotide AAUAAA, and their respective binding factors, CPEB and a cytoplasmic form of CPSF, control polyadenylation. The most proximal stimulus for polyadenylation is Eg2-catalyzed phosphorylation of CPEB serine 174. Here, we show that this phosphorylation event stimulates an interaction between CPEB and CPSF. This interaction is direct, does not require RNA tethering, and occurs through the 160 kDa subunit of CPSF. Eg2-stimulated and CPE-dependent polyadenylation is reconstituted in vitro using purified components. These results demonstrate that the molecular function of Eg2-phosphorylated CPEB is to recruit CPSF into an active cytoplasmic polyadenylation complex.