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TORC1 and TORC2 converge to regulate the SAGA co‐activator in response to nutrient availability
Author(s) -
Laboucarié Thomas,
Detilleux Dylane,
RodriguezMias Ricard A,
Faux Céline,
Romeo Yves,
FranzWachtel Mirita,
Krug Karsten,
Maček Boris,
Villén Judit,
Petersen Janni,
Helmlinger Dominique
Publication year - 2017
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.15252/embr.201744942
Subject(s) - library science , computer science
Gene expression regulation is essential for cells to adapt to changes in their environment. Co‐activator complexes have well‐established roles in transcriptional regulation, but less is known about how they sense and respond to signaling cues. We have previously shown that, in fission yeast, one such co‐activator, the SAGA complex, controls gene expression and the switch from proliferation to differentiation in response to nutrient availability. Here, using a combination of genetic, biochemical, and proteomic approaches, we show that SAGA responds to nutrients through the differential phosphorylation of its Taf12 component, downstream of both the TORC 1 and TORC 2 pathways. Taf12 phosphorylation increases early upon starvation and is controlled by the opposing activities of the PP 2A phosphatase, which is activated by TORC 1, and the TORC 2‐activated Gad8 AKT kinase. Mutational analyses suggest that Taf12 phosphorylation prevents cells from committing to differentiation until starvation reaches a critical level. Overall, our work reveals that SAGA is a direct target of nutrient‐sensing pathways and has uncovered a mechanism by which TORC 1 and TORC 2 converge to control gene expression and cell fate decisions.