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Schizosaccharomyces pombe AGC family kinase Gad8p forms a conserved signaling module with TOR and PDK1‐like kinases
Author(s) -
Matsuo Tomohiko,
Kubo Yoshiya,
Watanabe Yoshinori,
Yamamoto Masayuki
Publication year - 2003
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/cdg298
Subject(s) - biology , schizosaccharomyces pombe , kinase , microbiology and biotechnology , phosphorylation , tor signaling , schizosaccharomyces , protein kinase a , map2k7 , cyclin dependent kinase 2 , genetics , biochemistry , yeast , saccharomyces cerevisiae
The TOR protein is a phosphoinositide kinase‐related kinase widely conserved among eukaryotes. Fission yeast tor1 encodes an ortholog of TOR, which is required for sexual development and growth under stressed conditions. We isolated gad8 , which encodes a Ser/Thr kinase of the AGC family, as a high‐copy suppressor of the sterility of a tor1 mutant. Disruption of gad8 caused phenotypes similar to those of tor1 disruption. Gad8p was less phosphorylated and its kinase activity was undetectable in tor1 Δ cells. Three amino acid residues corresponding to conserved phosphorylation sites in the AGC family kinases, namely Thr387 in the activation loop, Ser527 in the turn motif and Ser546 in the hydrophobic motif, were important for the kinase activity of Gad8p. Tor1p was responsible for the phosphorylation of Ser527 and Ser546, whereas Ksg1p, a PDK1‐like kinase, appeared to phosphorylate Thr387 directly. Altogether, Tor1p, Ksg1p and Gad8p appear to constitute a signaling module for sexual development and growth under stressed conditions in fission yeast, which resembles the mTOR–PDK1–S6K1 system in mammals and may represent a basic signaling module ubiquitous in eukaryotes.