Premium
Functional dissection of the glucose signaling pathways that regulate the yeast glucose transporter gene ( HXT ) repressor Rgt1
Author(s) -
Jouandot David,
Roy Adhiraj,
Kim JeongHo
Publication year - 2011
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.23253
Subject(s) - repressor , snf3 , phosphorylation , activator (genetics) , biology , biochemistry , transcriptional regulation , microbiology and biotechnology , psychological repression , gene , chemistry , transcription factor , saccharomyces cerevisiae , gene expression
The yeast Rgt1 repressor is a bifunctional protein that acts as a transcriptional repressor and activator. Under glucose‐limited conditions, Rgt1 induces transcriptional repression by forming a repressive complex with its corepressors Mth1 and Std1. Here, we show that Rgt1 is converted from a transcriptional repressor into an activator under high glucose conditions and this occurs through two independent but consecutive events mediated by two glucose signaling pathways: (1) disruption of the repressive complex by the Rgt2/Snf3 pathway; (2) phosphorylation of Rgt1 by the cAMP‐dependent protein kinase (cAMP‐PKA) pathway. Rgt1 is phosphorylated by PKA at four serine residues within its amino‐terminal region, but this does not occur until the repressive complex is disrupted. While phosphorylation of any one of these sites is sufficient to enable Rgt1 to induce transcriptional activation, phosphorylation of all the sites results in the release of Rgt1 from DNA. We discuss how the bifunctional properties of Rgt1 are regulated through differential phosphorylation. J. Cell. Biochem. 112: 3268–3275, 2011. © 2011 Wiley Periodicals, Inc.