Open AccessA single gene encodes two isoforms of the p70 S6 kinase: activation upon mitogenic stimulation.
Author(s) -
Christoph Reinhard,
George Thomas,
Sara C. Kozma
Publication year - 1992
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.89.9.4052
Subject(s) - gene isoform , biology , clone (java method) , cdna library , complementary dna , microbiology and biotechnology , open reading frame , gene , p70 s6 kinase 1 , amino acid , kinase , peptide sequence , protein kinase a , signal transduction , biochemistry , pi3k/akt/mtor pathway
Previously, two cDNA clones were isolated from a rat liver or hepatoma cDNA library for the mitogenic-activated p70 S6 kinase (p70s6k). Except for a single amino acid change and a 23-amino acid N-terminal extension in the latter clone, the open reading frames of the two clones are identical. A probe common to both clones also revealed four distinct transcripts. Here, by using specific probes, it was possible to show which transcript corresponds to which clone and that both clones are derived from the same gene. Furthermore, analysis of in vitro translation products using specific antibodies demonstrates that both clones encode the p70s6k but that the clone harboring the 23-amino acid extension also encodes an additional isoform of the kinase, referred to as p85s6k. It could be shown by using the specific antibody to the p85s6k that this isoform of the kinase is present in rat liver and is activated after mitogenic stimulation of quiescent Swiss 3T3 cells.