scholarly journals Amino Acid Signaling in Saccharomyces cerevisiae: a Permease-Like Sensor of External Amino Acids and F-Box Protein Grr1p Are Required for Transcriptional Induction of the AGP1 Gene, Which Encodes a Broad-Specificity Amino Acid Permease

1999 ◽  
Vol 19 (2) ◽  
pp. 989-1001 ◽  
Author(s):  
Ismaïl Iraqui ◽  
Stephan Vissers ◽  
Florent Bernard ◽  
Johan-Owen de Craene ◽  
Eckhard Boles ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acids ◽  
Amino Acid ◽  
Glucose Sensors ◽  
Amino Acid Permease ◽  
Transporter Family ◽  
F Box Protein ◽  
Transcriptional Induction ◽  
Amino Acid Signaling ◽  
Broad Specificity

ABSTRACT The SSY1 gene of Saccharomyces cerevisiaeencodes a member of a large family of amino acid permeases. Compared to the 17 other proteins of this family, however, Ssy1p displays unusual structural features reminiscent of those distinguishing the Snf3p and Rgt2p glucose sensors from the other proteins of the sugar transporter family. We show here that SSY1 is required for transcriptional induction, in response to multiple amino acids, of theAGP1 gene encoding a low-affinity, broad-specificity amino acid permease. Total noninduction of the AGP1 gene in thessy1Δ mutant is not due to impaired incorporation of inducing amino acids. Conversely, AGP1 is strongly induced by tryptophan in a mutant strain largely deficient in tryptophan uptake, but it remains unexpressed in a mutant that accumulates high levels of tryptophan endogenously. Induction of AGP1requires Uga35p(Dal81p/DurLp), a transcription factor of the Cys6-Zn2 family previously shown to participate in several nitrogen induction pathways. Induction of AGP1by amino acids also requires Grr1p, the F-box protein of the SCFGrr1 ubiquitin-protein ligase complex also required for transduction of the glucose signal generated by the Snf3p and Rgt2p glucose sensors. Systematic analysis of amino acid permease genes showed that Ssy1p is involved in transcriptional induction of at least five genes in addition to AGP1. Our results show that the amino acid permease homologue Ssy1p is a sensor of external amino acids, coupling availability of amino acids to transcriptional events. The essential role of Grr1p in this amino acid signaling pathway lends further support to the hypothesis that this protein participates in integrating nutrient availability with the cell cycle.

scholarly journals Constitutive and Hyperresponsive Signaling by Mutant Forms of Saccharomyces cerevisiae Amino Acid Sensor Ssy1

2003 ◽  
Vol 2 (5) ◽  
pp. 922-929 ◽  
Author(s):  
Richard F. Gaber ◽  
Kim Ottow ◽  
Helge A. Andersen ◽  
Morten C. Kielland-Brandt
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Direct Interaction ◽  
Acid Transport ◽  
Amino Acid Permease ◽  
Amino Acid Permeases ◽  
Mutant Forms ◽  
Amino Acid Sensor ◽  
Transcriptional Induction ◽  
Amino Acid Signaling

ABSTRACT Sensing of extracellular amino acids results in transcriptional induction of amino acid permease genes in yeast. Ssy1, a membrane protein resembling amino acid permeases, is required for signaling but is apparently unable to transport amino acids and is thus believed to be a sensor. By using a novel genetic screen in which potassium uptake was made dependent on amino acid signaling, we obtained gain-of-function mutations in SSY1. Some alleles confer inducer-independent signaling; others increase the apparent affinity for inducers. The results reveal that amino acid transport is not required for signaling and support the notion that sensing by Ssy1 occurs via its direct interaction with extracellular amino acids.

scholarly journals The External Amino Acid Signaling Pathway Promotes Activation of Stp1 and Uga35/Dal81 Transcription Factors for Induction of the AGP1 Gene in Saccharomyces cerevisiae

Genetics ◽  
2004 ◽  
Vol 166 (4) ◽  
pp. 1727-1739 ◽  
Author(s):  
Fadi Abdel-Sater ◽  
Ismaïl Iraqui ◽  
Antonio Urrestarazu ◽  
Bruno André
Keyword(s):  
Amino Acids ◽  
Transcription Factor ◽  
Transcription Factors ◽  
Amino Acid ◽  
Signaling Pathway ◽  
Nitrogen Supply ◽  
Upstream Region ◽  
Gata Factor ◽  
Amino Acid Permease ◽  
Amino Acid Signaling

Abstract Yeast cells respond to the presence of amino acids in their environment by inducing transcription of several amino acid permease genes including AGP1, BAP2, and BAP3. The signaling pathway responsible for this induction involves Ssy1, a permease-like sensor of external amino acids, and culminates with proteolytic cleavage and translocation to the nucleus of the zinc-finger proteins Stp1 and Stp2, the lack of which abolishes induction of BAP2 and BAP3. Here we show that Stp1—but not Stp2—plays an important role in AGP1 induction, although significant induction of AGP1 by amino acids persists in stp1 and stp1 stp2 mutants. This residual induction depends on the Uga35/Dal81 transcription factor, indicating that the external amino acid signaling pathway activates not only Stp1 and Stp2, but also another Uga35/Dal81-dependent transcriptional circuit. Analysis of the AGP1 gene’s upstream region revealed that Stp1 and Uga35/Dal81 act synergistically through a 21-bp cis-acting sequence similar to the UASAA element previously found in the BAP2 and BAP3 upstream regions. Although cells growing under poor nitrogen-supply conditions display much higher induction of AGP1 expression than cells growing under good nitrogen-supply conditions, the UASAA itself is totally insensitive to nitrogen availability. Nitrogen-source control of AGP1 induction is mediated by the GATA factor Gln3, likely acting through adjacent 5′-GATA-3′ sequences, to amplify the positive effect of UASAA. Our data indicate that Stp1 may act in combination with distinct sets of transcription factors, according to the gene context, to promote induction of transcription in response to external amino acids. The data also suggest that Uga35/Dal81 is yet another transcription factor under the control of the external amino acid sensing pathway. Finally, the data show that the TOR pathway mediating global nitrogen control of transcription does not interfere with the external amino acid signaling pathway.

scholarly journals Different Ubiquitin Signals Act at the Golgi and Plasma Membrane to Direct GAP1 Trafficking

2008 ◽  
Vol 19 (7) ◽  
pp. 2962-2972 ◽  
Author(s):  
April L. Risinger ◽  
Chris A. Kaiser
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acids ◽  
Plasma Membrane ◽  
Amino Acid ◽  
Protein Sorting ◽  
High Capacity ◽  
Amino Acid Permease ◽  
Acid Addition ◽  
Amino Acid Levels ◽  
General Amino Acid Permease

The high capacity general amino acid permease, Gap1p, in Saccharomyces cerevisiae is distributed between the plasma membrane and internal compartments according to availability of amino acids. When internal amino acid levels are low, Gap1p is localized to the plasma membrane where it imports available amino acids from the medium. When sufficient amino acids are imported, Gap1p at the plasma membrane is endocytosed and newly synthesized Gap1p is delivered to the vacuole; both sorting steps require Gap1p ubiquitination. Although it has been suggested that identical trans-acting factors and Gap1p ubiquitin acceptor sites are involved in both processes, we define unique requirements for each of the ubiquitin-mediated sorting steps involved in delivery of Gap1p to the vacuole upon amino acid addition. Our finding that distinct ubiquitin-mediated sorting steps employ unique trans-acting factors, ubiquitination sites on Gap1p, and types of ubiquitination demonstrates a previously unrecognized level of specificity in ubiquitin-mediated protein sorting.

scholarly journals Deletion of RTS1, Encoding a Regulatory Subunit of Protein Phosphatase 2A, Results in Constitutive Amino Acid Signaling via Increased Stp1p Processing

2006 ◽  
Vol 5 (1) ◽  
pp. 174-179 ◽  
Author(s):  
Nadine Eckert-Boulet ◽  
Katrin Larsson ◽  
Boqian Wu ◽  
Peter Poulsen ◽  
Birgitte Regenberg ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Protein Phosphatase ◽  
Protein Phosphatase 2A ◽  
Regulatory Subunit ◽  
Mutant Library ◽  
Amino Acid Permease ◽  
Phosphatase 2A ◽  
Amino Acid Sensing ◽  
Amino Acid Signaling

ABSTRACT In Saccharomyces cerevisiae, extracellular amino acids are sensed at the plasma membrane by the SPS sensor, consisting of the transporter homologue Ssy1p, Ptr3p, and the endoprotease Ssy5p. Amino acid sensing results in proteolytic truncation of the transcription factors Stp1p and Stp2p, followed by their relocation from the cytoplasm to the nucleus, where they activate transcription of amino acid permease genes. We screened a transposon mutant library for constitutively signaling mutants, with the aim of identifying down-regulating components of the SPS-mediated pathway. Three isolated mutants were carrying a transposon in the RTS1 gene, which encodes a regulatory subunit of protein phosphatase 2A. We investigated the basal activity of the AGP1 and BAP2 promoters in rts1Δ cells and found increased transcription from these promoters, as well as increased Stp1p processing, even in the absence of amino acids. Based on our findings we propose that the phosphatase complex containing Rts1p keeps the SPS-mediated pathway down-regulated in the absence of extracellular amino acids by dephosphorylating a component of the pathway.

scholarly journals Changes in membrane proteins associated with inhibition of the general amino acid permease of yeast (Saccharomyces cerevisiae)

1981 ◽  
Vol 196 (2) ◽  
pp. 531-536 ◽  
Author(s):  
J R Woodward ◽  
H L Kornberg
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acids ◽  
Amino Acid ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Wild Type ◽  
Amino Acid Permease ◽  
Yeast Saccharomyces Cerevisiae ◽  
General Amino Acid Permease ◽  
Wild Type Yeast

The general amino acid permease (‘Gap’) system of the wild-type yeast (Saccharomyces cerevisiae) strain Y185 is inhibited by the uptake and accumulation of its substrate amino acids. Surprisingly, this inhibition persists even after ‘pools’ of amino acids, accumulated initially, have returned to normal sizes. Recovery from this inhibition depends on a supply of energy and involves the synthesis of a membrane protein component of the Gap system.

scholarly journals Transcriptional Induction by Aromatic Amino Acids in Saccharomyces cerevisiae

1999 ◽  
Vol 19 (5) ◽  
pp. 3360-3371 ◽  
Author(s):  
Ismaïl Iraqui ◽  
Stéphan Vissers ◽  
Bruno André ◽  
Antonio Urrestarazu
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Aromatic Amino Acids ◽  
Positive Control ◽  
General Factor ◽  
Amino Acid Transporters ◽  
Amino Acid Permease ◽  
Gene Encoding ◽  
Inducer Exclusion ◽  
Transcriptional Induction

ABSTRACT Aromatic aminotransferase II, product of the ARO9 gene, catalyzes the first step of tryptophan, phenylalanine, and tyrosine catabolism in Saccharomyces cerevisiae. ARO9 expression is under the dual control of specific induction and nitrogen source regulation. We have here identified UASaro, a 36-bp upstream element necessary and sufficient to promote transcriptional induction of reporter gene expression in response to tryptophan, phenylalanine, or tyrosine. We then isolated mutants in which UASaro-mediated ARO9 transcription is partially or totally impaired. Mutations abolishingARO9 induction affect a gene called ARO80(YDR421w), coding for a Zn2Cys6 family transcription factor. A sequence highly similar to UASaro was found upstream from theYDR380w gene encoding a homolog of bacterial indolepyruvate decarboxylase. In yeast, this enzyme is postulated to catalyze the second step of tryptophan catabolism to tryptophol. We show that ARO9 and YDR380w(named ARO10) have similar patterns of transcriptional regulation and are both under the positive control of Aro80p. Nitrogen regulation of ARO9 expression seems not directly to involve the general factor Ure2p, Gln3p, Nil1p, Uga43p, or Gzf3p.ARO9 expression appears, rather, to be mainly regulated by inducer exclusion. Finally, we show that Gap1p, the general amino acid permease, and Wap1p (Ycl025p), a newly discovered inducible amino acid permease with broad specificity, are the main aromatic amino acid transporters for catabolic purposes.

scholarly journals Growth Inhibition by Amino Acids in Saccharomyces cerevisiae

2020 ◽  
Vol 9 (1) ◽  
pp. 7
Author(s):  
Stephanie J. Ruiz ◽  
Joury S. van ’t Klooster ◽  
Frans Bianchi ◽  
Bert Poolman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acids ◽  
Amino Acid ◽  
Growth Defect ◽  
Amino Acid Transporters ◽  
Amino Acid Permease ◽  
Cytosolic Ph ◽  
Acid Sensitivity ◽  
Growth Inhibitory

Amino acids are essential metabolites but can also be toxic when present at high levels intracellularly. Substrate-induced downregulation of amino acid transporters in Saccharomyces cerevisiae is thought to be a mechanism to avoid this toxicity. It has been shown that unregulated uptake by the general amino acid permease Gap1 causes cells to become sensitive to amino acids. Here, we show that overexpression of eight other amino acid transporters (Agp1, Bap2, Can1, Dip5, Gnp1, Lyp1, Put4, or Tat2) also induces a growth defect when specific single amino acids are present at concentrations of 0.5–5 mM. We can now state that all proteinogenic amino acids, as well as the important metabolite ornithine, are growth inhibitory to S. cerevisiae when transported into the cell at high enough levels. Measurements of initial transport rates and cytosolic pH show that toxicity is due to amino acid accumulation and not to the influx of co-transported protons. The amino acid sensitivity phenotype is a useful tool that reports on the in vivo activity of transporters and has allowed us to identify new transporter-specific substrates.

scholarly journals MCH4is a multicopy suppressor of glycine toxicity inSaccharomyces cerevisiae

2019 ◽  
Author(s):  
Artem V. Melnykov ◽  
Elliot L. Elson
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acids ◽  
Amino Acid ◽  
Osmotic Shock ◽  
Inhibitory Effects ◽  
Amino Acid Permease ◽  
Multicopy Suppressor ◽  
Low Concentrations ◽  
General Amino Acid Permease ◽  
Acid Toxicity

AbstractSaccharomyces cerevisiaecan either import amino acids from the surrounding or synthesize inside the cell, and both processes are tightly regulated. Disruption of such regulation can result in amino acid toxicity to the cell through mechanisms that are poorly understood. In this study we make use of a mutant strain with deregulated general amino acid permease gene whose growth is inhibited by low concentrations of several amino acids. We carry out multicopy suppression screen with several toxic amino acids and identifyMCH4as a gene that suppresses inhibitory effects of glycine. We find that expression ofMCH4is regulated by osmotic shock but not other kinds of stress. These findings are discussed in the context of possible mechanisms of amino acid toxicity.

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