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The activation mechanism of plant S6 kinase (S6K), a substrate of TOR kinase, is different from that of mammalian S6K
Author(s) -
Yaguchi Misaki,
Ikeya Shun,
Kozaki Akiko
Publication year - 2020
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1002/1873-3468.13661
Subject(s) - p70 s6 kinase 1 , phosphorylation , kinase , yeast , biology , microbiology and biotechnology , biochemistry , protein kinase b
The S6 kinases (S6Ks) are known to be activated by the target of rapamycin through phosphorylation of their hydrophobic motif (HM). However, our previous research showed that the HM site of plant S6Ks is not phosphorylated and is not essential for their activity in yeast cells lacking Ypk3, an ortholog of mammalian S6K. Here, we demonstrate that the HM site of mammalian S6Ks is phosphorylated and is indispensable for their activity in yeast ypk3∆ cells. Furthermore, pseudo‐phosphorylation at the HM site of plant S6Ks results in regaining of activity that is lost due to mutation in the conserved phosphorylation sites, namely the T‐loop and Turn motif. These results indicate the activation mechanism of plant S6Ks is different from that of mammals.