Phosphorylation of CPEB by Eg2 mediates the recruitment of CPSF into an active cytoplasmic polyadenylation complex.
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.
Mendez
R
R
Department of Molecular Genetics and Microbiology University of Massachusetts Medical School, Worcester, MA 01655, USA.
Murthy
K G
KG
Ryan
K
K
Manley
J L
JL
Richter
J D
JD
D000818:Animals; D064127:Aurora Kinases; D001483:Base Sequence; D018797:Cell Cycle Proteins; D002467:Cell Nucleus / Q000378:metabolism; D022083:Cytoplasmic Structures / Q000737:chemistry* / Q000378:metabolism*; D046911:Macromolecular Substances; D008970:Molecular Weight; D009865:Oocytes / Q000166:cytology / Q000378:metabolism; D010766:Phosphorylation; D026723:Polyadenylation; D011233:Precipitin Tests; D011485:Protein Binding; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D021122:Protein Subunits; D021381:Protein Transport; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D013816:Thermodynamics; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism*; D029867:Xenopus Proteins; D014982:Xenopus laevis / Q000378:metabolism*; D039221:mRNA Cleavage and Polyadenylation Factors
D018797:Cell Cycle Proteins; C490388:Cpeb1 protein, Xenopus; D046911:Macromolecular Substances; D021122:Protein Subunits; D016601:RNA-Binding Proteins; D014157:Transcription Factors; D029867:Xenopus Proteins; D039221:mRNA Cleavage and Polyadenylation Factors; D011494:Protein Kinases; C112134:AURKA protein, Xenopus; D064127:Aurora Kinases; D017346:Protein Serine-Threonine Kinases