title: Embryonic poly(A)-binding protein (ePAB) phosphorylation is required for Xenopus oocyte maturation.
abstract: Oocyte maturation and early embryonic development require the cytoplasmic polyadenylation and concomitant translational activation of stored maternal mRNAs. ePAB [embryonic poly(A)-binding protein, also known as ePABP and PABPc1-like] is a multifunctional post-transcriptional regulator that binds to poly(A) tails. In the present study we find that ePAB is a dynamically modified phosphoprotein in Xenopus laevis oocytes and show by mutation that phosphorylation at a four residue cluster is required for oocyte maturation. We further demonstrate that these phosphorylations are critical for cytoplasmic polyadenylation, but not for ePAB's inherent ability to promote translation. Our results provide the first insight into the role of post-translational modifications in regulating PABP protein activity in vivo.
authors.affiliation: Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University School of Medicine, 310 Cedar Street, LSOG 304D, New Haven, CT 06520, USA.
authors.forename: Kyle
authors.initials: K
authors.lastname: Friend
authors.forename: Matthew
authors.initials: M
authors.lastname: Brook
authors.forename: F Betül
authors.initials: FB
authors.lastname: Bezirci
authors.forename: Michael D
authors.initials: MD
authors.lastname: Sheets
authors.forename: Nicola K
authors.initials: NK
authors.lastname: Gray
authors.forename: Emre
authors.initials: E
authors.lastname: Seli
mesh_terms: D000818:Animals; D015153:Blotting, Western; D003593:Cytoplasm / Q000378:metabolism; D005260:Female; D005455:Fluorescent Antibody Technique; D018507:Gene Expression Regulation, Developmental; D047468:Immunoprecipitation; D009154:Mutation / Q000235:genetics; D009865:Oocytes / Q000166:cytology* / Q000378:metabolism; D009866:Oogenesis / Q000502:physiology; D010766:Phosphorylation; D011061:Poly A / Q000378:metabolism*; D039102:Poly(A)-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D026723:Polyadenylation; D014176:Protein Biosynthesis; D011499:Protein Processing, Post-Translational; D012333:RNA, Messenger / Q000235:genetics; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis / Q000196:embryology* / Q000378:metabolism*
chemical_list: C424905:PABPC4 protein, Xenopus; D039102:Poly(A)-Binding Proteins; D012333:RNA, Messenger; D029867:Xenopus Proteins; D011061:Poly A