title: cDNA cloning of a novel B subunit of Xenopus protein phosphatase 2A and its biological activity in oocytes.
abstract: We have cloned a cDNA encoding a novel B regulatory subunit of protein phosphatase 2A (PP2A) from a Xenopus oocyte cDNA library. The novel B subunit, termed B beta', shows the strongest overall sequence similarity to, but a distinct N-terminal sequence from, the beta isoform of the human/rat B subunit. When expressed ectopically in Xenopus oocytes, the B beta' isoform can augment the endogenous PP2A activity and inhibit oocyte maturation induced by progesterone. These results suggest that the B beta' isoform can form a complex with other PP2A subunits to make a trimeric PP2A holoenzyme in Xenopus oocytes and may negatively control the initiation of oocyte maturation.
authors.affiliation: Department of Biology, Faculty of Science, Kyushu University, Fukuoka, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Iwashita
authors.forename: H
authors.initials: H
authors.lastname: Shima
authors.forename: M
authors.initials: M
authors.lastname: Nagao
authors.forename: N
authors.initials: N
authors.lastname: Sagata
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary; D008969:Molecular Sequence Data; D009865:Oocytes / Q000201:enzymology*; D010749:Phosphoprotein Phosphatases / Q000737:chemistry / Q000235:genetics*; D054648:Protein Phosphatase 2; D051381:Rats; D017386:Sequence Homology, Amino Acid; D014981:Xenopus
chemical_list: D018076:DNA, Complementary; D010749:Phosphoprotein Phosphatases; D054648:Protein Phosphatase 2