Snf1 Protein Kinase and the Repressors Nrg1 and Nrg2 Regulate FLO11, Haploid Invasive Growth, and Diploid Pseudohyphal Differentiation

Abstract

The Snf1 protein kinase of Saccharomyces cerevisiae is important for many cellular responses to glucose limitation, including haploid invasive growth. We show here that Snf1 regulates transcription of FLO11, which encodes a cell surface glycoprotein required for invasive growth. We further show that Nrg1 and Nrg2, two repressor proteins that interact with Snf1, function as negative regulators of invasive growth and as repressors of FLO11. We also examined the role of Snf1, Nrg1, and Nrg2 in two other Flo11-dependent processes. Mutations affected the initiation of biofilm formation, which is glucose sensitive, but also affected diploid pseudohyphal differentiation, thereby unexpectedly implicating Snf1 in a response to nitrogen limitation. Deletion of the NRG1 and NRG2 genes suppressed the defects of a snf1 mutant in all of these processes. These findings suggest a model in which the Snf1 kinase positively regulates Flo11-dependent developmental events by antagonizing Nrg-mediated repression of the FLO11 gene.

Nsf1/Ypl230w participates in transcriptional activation during non-fermentative growth and in response to salt stress in Saccharomyces cerevisiae

“…Nrg1 and its homologue Nrg2 have both been shown to interact with Snf1 (Vyas et al, 2001). Snf1 inactivates Nrg1 (Kuchin et al, 2002;Vyas et al, 2001), and the transcription of NRG1 is inhibited by Rim101 under alkaline pH and salt stress (Lamb & Mitchell, 2003). However, the levels of NRG1 transcription and subsequent protein synthesis increase in the presence of non-fermentable carbon sources, while the level of Nrg2 decreases (Berkey et al, 2004).…”

“…Its function has been linked to glucose repression (Kuchin et al, 2002;Zhou & Winston, 2001), adaptation to stress via the regulation of STRE (STress REsponse) element-containing genes (Vyas et al, 2005), and adaptation to alkaline pH and salt stress (Lamb & Mitchell, 2003). Nrg1 and its homologue Nrg2 have both been shown to interact with Snf1 (Vyas et al, 2001).…”

Activation of yeast Snf1 and mammalian AMP-activated protein kinase by upstream kinases

“…The signals that control Snf1 activity in response to glucose levels are not understood, although the AMP:ATP ratio may have a role under some conditions (11). Snf1 also affects meiosis and sporulation, filamentous invasive growth (12)(13)(14), and aging (15).…”

Overproduction of non‐translatable mRNA silences. The transcription of Ty1 retrotransposons in S. cerevisiae via functional inactivation of the nuclear cap‐binding complex and subsequent hyperstimulation of the TORC1 pathway

“…The Glc7/Reg1 phosphatase functionally antagonizes the Snf1-Snf4 AMP-activated protein kinase. Snf1 regulates a wide range of responses glucose deprivation (Hardie et al, 1998), and it also mediates the diploid pseudohyphal differentiation response to nitrogen limitation (Kuchin et al, 2002). Importantly, Snf1 is negatively regulated by the TORC1 kinase (Bertram et al, 2002;Mayordomo et al, 2002;Orlova et al, 2006).…”