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Target of rapamycin complex 1 and Tap42‐associated phosphatases are required for sensing changes in nitrogen conditions in the yeast Saccharomyces cerevisiae
Author(s) -
Li Jinmei,
Yan Gonghong,
Liu Sichi,
Jiang Tong,
Zhong Mingming,
Yuan Wenjie,
Chen Shaoxian,
Zheng Yin,
Jiang Yong,
Jiang Yu
Publication year - 2017
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.13858
Subject(s) - phosphatase , biology , saccharomyces cerevisiae , yeast , nitrogen , transcription factor , kinase , biochemistry , nitrogen cycle , microbiology and biotechnology , phosphorylation , chemistry , gene , organic chemistry
Summary In yeast target of rapamycin complex 1 (TORC1) and Tap42‐associated phosphatases regulate expression of genes involved in nitrogen limitation response and the nitrogen discrimination pathway. However, it remains unclear whether TORC1 and the phosphatases are required for sensing nitrogen conditions. Utilizing temperature sensitive mutants of tor2 and tap42 , we examined the role of TORC1 and Tap42 in nuclear entry of Gln3, a key transcription factor in yeast nitrogen metabolism, in response to changes in nitrogen conditions. Our data show that TORC1 is essential for Gln3 nuclear entry upon nitrogen limitation and downshift in nitrogen quality. However, Tap42‐associated phosphatases are required only under nitrogen limitation condition. In cells grown in poor nitrogen medium, the nitrogen permease reactivator kinase (Npr1) inhibits TORC1 activity and alters its association with Tap42, rendering Tap42‐associated phosphatases unresponsive to nitrogen limitation. These findings demonstrate a direct role for TORC1 and Tap42‐associated phosphatases in sensing nitrogen conditions and unveil an Npr1‐dependent mechanism that controls TORC1 and the phosphatases in response to changes in nitrogen quality.