scholarly journals Starvation Induces Vacuolar Targeting and Degradation of the Tryptophan Permease in Yeast

1999 ◽  
Vol 146 (6) ◽  
pp. 1227-1238 ◽  
Author(s):  
Thomas Beck ◽  
Anja Schmidt ◽  
Michael N. Hall
Keyword(s):  
Amino Acid ◽  
Secretory Pathway ◽  
Nutrient Deprivation ◽  
Tor Signaling ◽  
Amino Acid Permease ◽  
High Affinity ◽  
Lysine Residues ◽  
Amino Acid Permeases ◽  
General Amino Acid Permease ◽  
Ubiquitination Machinery

In Saccharomyces cerevisiae, amino acid permeases are divided into two classes. One class, represented by the general amino acid permease GAP1, contains permeases regulated in response to the nitrogen source. The other class, including the high affinity tryptophan permease, TAT2, consists of the so-called constitutive permeases. We show that TAT2 is regulated at the level of protein stability. In exponentially growing cells, TAT2 is in the plasma membrane and also accumulates in internal compartments of the secretory pathway. Upon nutrient deprivation or rapamycin treatment, TAT2 is transported to and degraded in the vacuole. The ubiquitination machinery and lysine residues within the NH2-terminal 31 amino acids of TAT2 mediate ubiquitination and degradation of the permease. Starvation-induced degradation of internal TAT2 is blocked in sec18, sec23, pep12, and vps27 mutants, but not in sec4, end4, and apg1 mutants, suggesting that, upon nutrient limitation, internal TAT2 is diverted from the late secretory pathway to the vacuolar pathway. Furthermore, our results suggest that TAT2 stability and sorting are controlled by the TOR signaling pathway, and regulated inversely to that of GAP1.

Ammonia regulation of amino acid permeases in Saccharomyces cerevisiae

1983 ◽  
Vol 3 (4) ◽  
pp. 672-683
Author(s):  
W E Courchesne ◽  
B Magasanik
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Cytoplasmic Membrane ◽  
Nitrogen Sources ◽  
Amino Acid Permease ◽  
Inducer Exclusion ◽  
Amino Acid Permeases ◽  
General Amino Acid Permease ◽  
State Growth ◽  
And Control

The activities of the proline-specific permease (PUT4) and the general amino acid permease (GAP1) of Saccharomyces cerevisiae vary 70- to 140-fold in response to the nitrogen source of the growth medium. The PUT4 and GAP1 permease activities are regulated by control of synthesis and control of activity. These permeases are irreversibly inactivated by addition of ammonia or glutamine, lowering the activity to that found during steady-state growth on these nitrogen sources. Mutants altered in the regulation of the PUT4 permease (Per-) have been isolated. The mutations in these strains are pleiotropic and affect many other permeases, but have no direct effect on various cytoplasmic enzymes involved in nitrogen assimilation. In strains having one class of mutations (per1), ammonia inactivation of the PUT4 and GAP1 permeases did not occur, whereas glutamate and glutamine inactivation did. Thus, there appear to be two independent inactivation systems, one responding to ammonia and one responding to glutamate (or a metabolite of glutamate). The mutations were found to be nuclear and recessive. The inactivation systems are constitutive and do not require transport of the effector molecules per se, apparently operating on the inside of the cytoplasmic membrane. The ammonia inactivation was found not to require a functional glutamate dehydrogenase (NADP). These mutants were used to show that ammonia exerts control of arginase synthesis largely by inducer exclusion. This may be the primary mode of nitrogen regulation for most nitrogen-regulated enzymes of S. cerevisiae.

scholarly journals Two FK506 resistance-conferring genes in Saccharomyces cerevisiae, TAT1 and TAT2, encode amino acid permeases mediating tyrosine and tryptophan uptake.

1994 ◽  
Vol 14 (10) ◽  
pp. 6597-6606 ◽  
Author(s):  
A Schmidt ◽  
M N Hall ◽  
A Koller
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
T Cell Activation ◽  
Cell Activation ◽  
Amino Acid Permease ◽  
High Affinity ◽  
New Genes ◽  
Eukaryotic Microorganisms ◽  
Amino Acid Permeases ◽  
Tryptophan Uptake

The macrocyclic lactone FK506 exerts immunosuppressive effects on T lymphocytes by interfering with signal transduction leading to T-cell activation and also inhibits the growth of eukaryotic microorganisms, including Saccharomyces cerevisiae. We reported previously that an FK506-sensitive target in S. cerevisiae is required for amino acid import and that overexpression of two new genes, TAT1 and TAT2 (formerly called TAP1 and TAP2), confers resistance to the drug. Here we report that TAT1 and TAT2 encode novel members of the yeast amino acid permease family composed of integral membrane proteins that share 30 to 40% identity. TAT1 is the tyrosine high-affinity transporter, which also mediates low-affinity or low-capacity uptake of tryptophan. TAT2 is the tryptophan high-affinity transporter. FK506 does not reduce the levels of TAT1 and TAT2 transcripts, indicating that the inhibition of amino acid transport by the drug is posttranscriptional.

scholarly journals Uptake of the β-Lactam Precursor α-Aminoadipic Acid in Penicillium chrysogenum Is Mediated by the Acidic and the General Amino Acid Permease

2004 ◽  
Vol 70 (8) ◽  
pp. 4775-4783 ◽  
Author(s):  
Hein Trip ◽  
Melchior E. Evers ◽  
Jan A. K. W. Kiel ◽  
Arnold J. M. Driessen
Keyword(s):  
Amino Acid ◽  
Penicillium Chrysogenum ◽  
Acid Uptake ◽  
Penicillin Production ◽  
Acid Transport ◽  
Acidic Amino Acid ◽  
Amino Acid Permease ◽  
Relative Contribution ◽  
Amino Acid Permeases ◽  
General Amino Acid Permease

ABSTRACT External addition of the β-lactam precursor α-aminoadipic acid to the filamentous fungus Penicillium chrysogenum leads to an increased intracellular α-aminoadipic acid concentration and an increase in penicillin production. The exact route for α-aminoadipic acid uptake is not known, although the general amino acid and acidic amino acid permeases have been implicated in this process. Their corresponding genes, PcGAP1 and PcDIP5, of P. chrysogenum were cloned and functionally expressed in a mutant of Saccharomyces cerevisiae (M4276) in which the acidic amino acid and general amino acid permease genes (DIP5 and GAP1, respectively) are disrupted. Transport assays show that both PcGap1 and PcDip5 mediated the uptake of α-aminoadipic acid, although PcGap1 showed a higher affinity for α-aminoadipic acid than PcDip5 (Km values, 230 and 800 μM, respectively). Leucine strongly inhibits α-aminoadipic acid transport via PcGap1 but not via PcDip5. This difference was exploited to estimate the relative contribution of each transport system to the α-aminoadipic acid flux in β-lactam-producing P. chrysogenum. The transport measurements demonstrate that both PcGap1 and PcDip5 contribute to the α-aminoadipic acid flux.

scholarly journals Ammonia regulation of amino acid permeases in Saccharomyces cerevisiae.

1983 ◽  
Vol 3 (4) ◽  
pp. 672-683 ◽  
Author(s):  
W E Courchesne ◽  
B Magasanik
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Cytoplasmic Membrane ◽  
Nitrogen Sources ◽  
Amino Acid Permease ◽  
Inducer Exclusion ◽  
Amino Acid Permeases ◽  
General Amino Acid Permease ◽  
State Growth ◽  
And Control

The activities of the proline-specific permease (PUT4) and the general amino acid permease (GAP1) of Saccharomyces cerevisiae vary 70- to 140-fold in response to the nitrogen source of the growth medium. The PUT4 and GAP1 permease activities are regulated by control of synthesis and control of activity. These permeases are irreversibly inactivated by addition of ammonia or glutamine, lowering the activity to that found during steady-state growth on these nitrogen sources. Mutants altered in the regulation of the PUT4 permease (Per-) have been isolated. The mutations in these strains are pleiotropic and affect many other permeases, but have no direct effect on various cytoplasmic enzymes involved in nitrogen assimilation. In strains having one class of mutations (per1), ammonia inactivation of the PUT4 and GAP1 permeases did not occur, whereas glutamate and glutamine inactivation did. Thus, there appear to be two independent inactivation systems, one responding to ammonia and one responding to glutamate (or a metabolite of glutamate). The mutations were found to be nuclear and recessive. The inactivation systems are constitutive and do not require transport of the effector molecules per se, apparently operating on the inside of the cytoplasmic membrane. The ammonia inactivation was found not to require a functional glutamate dehydrogenase (NADP). These mutants were used to show that ammonia exerts control of arginase synthesis largely by inducer exclusion. This may be the primary mode of nitrogen regulation for most nitrogen-regulated enzymes of S. cerevisiae.

scholarly journals Two FK506 resistance-conferring genes in Saccharomyces cerevisiae, TAT1 and TAT2, encode amino acid permeases mediating tyrosine and tryptophan uptake

1994 ◽  
Vol 14 (10) ◽  
pp. 6597-6606
Author(s):  
A Schmidt ◽  
M N Hall ◽  
A Koller
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
T Cell Activation ◽  
Cell Activation ◽  
Amino Acid Permease ◽  
High Affinity ◽  
New Genes ◽  
Eukaryotic Microorganisms ◽  
Amino Acid Permeases ◽  
Tryptophan Uptake

The macrocyclic lactone FK506 exerts immunosuppressive effects on T lymphocytes by interfering with signal transduction leading to T-cell activation and also inhibits the growth of eukaryotic microorganisms, including Saccharomyces cerevisiae. We reported previously that an FK506-sensitive target in S. cerevisiae is required for amino acid import and that overexpression of two new genes, TAT1 and TAT2 (formerly called TAP1 and TAP2), confers resistance to the drug. Here we report that TAT1 and TAT2 encode novel members of the yeast amino acid permease family composed of integral membrane proteins that share 30 to 40% identity. TAT1 is the tyrosine high-affinity transporter, which also mediates low-affinity or low-capacity uptake of tryptophan. TAT2 is the tryptophan high-affinity transporter. FK506 does not reduce the levels of TAT1 and TAT2 transcripts, indicating that the inhibition of amino acid transport by the drug is posttranscriptional.

scholarly journals The absorption of protons with specific amino acids and carbohydrates by yeast

1973 ◽  
Vol 134 (4) ◽  
pp. 1031-1043 ◽  
Author(s):  
A. Seaston ◽  
C. Inkson ◽  
A. A. Eddy
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Permease ◽  
Maximum Value ◽  
Mutant Strains ◽  
Fast Absorption ◽  
Proton Uptake ◽  
Amino Acid Permeases ◽  
General Amino Acid Permease

1. Proton uptake in the presence of various amino acids was studied in washed yeast suspensions containing deoxyglucose and antimycin to inhibit energy metabolism. A series of mutant strains of Saccharomyces cerevisiae with defective amino acid permeases was used. The fast absorption of glycine, l-citrulline and l-methionine through the general amino acid permease was associated with the uptake of about 2 extra equivalents of protons per mol of amino acid absorbed, whereas the slower absorption of l-methionine, l-proline and, possibly, l-arginine through their specific permeases was associated with about 1 proton equivalent. l-Canavanine and l-lysine were also absorbed with 1–2 equivalents of protons. 2. A strain of Saccharomyces carlsbergensis behaved similarly with these amino acids. 3. Preparations of the latter yeast grown with maltose subsequently absorbed it with 2–3 equivalents of protons. The accelerated rate of proton uptake increased up to a maximum value with the maltose concentration (Km=1.6mm). The uptake of protons was also faster in the presence of α-methylglucoside and sucrose, but not in the presence of glucose, galactose or 2-deoxyglucose. All of these compounds except the last could cause acid formation. The uptake of protons induced by maltose, α-methylglucoside and sucrose was not observed when the yeast was grown with glucose, although acid was then formed both from sucrose and glucose. 4. A strain of Saccharomyces fragilis that both fermented and formed acid from lactose absorbed extra protons in the presence of lactose. 5. The observations show that protons were co-substrates in the systems transporting the amino acids and certain of the carbohydrates.

scholarly journals Control of Amino Acid Permease Sorting in the Late Secretory Pathway of Saccharomyces cerevisiae by SEC13, LST4, LST7 and LST78

Genetics ◽  
1997 ◽  
Vol 147 (4) ◽  
pp. 1569-1584 ◽  
Author(s):  
Kevin J Roberg ◽  
Stephen Bickel ◽  
Neil Rowley ◽  
Chris A Kaiser
Keyword(s):  
Amino Acid ◽  
Cell Surface ◽  
Secretory Pathway ◽  
Protein Transport ◽  
Secretory Vesicle ◽  
Temperature Sensitive ◽  
Permissive Temperature ◽  
Amino Acid Permease ◽  
New Genes ◽  
Amino Acid Permeases

Abstract The SEC13 gene was originally identified by temperature-sensitive mutations that block all protein transport from the ER to the Golgi. We have found that at a permissive temperature for growth, the sec13-1 mutation selectively blocks transport of the nitrogen-regulated amino acid permease, Gaplp, from the Golgi to the plasma membrane, but does not affect the activity of constitutive permeases such as Hip1p, Can1p, or Lyp1p. Different alleles of SEC13 exhibit different relative effects on protein transport from the ER to the Golgi, or on Gap1p activity, indicating distinct requirements for SEC13 function at two different steps in the secretory pathway. Three new genes, LST4, LST7, and LSTB, were identified that are also required for amino acid permease transport from the Golgi to the cell surface. Mutations in LST4 and LST7 reduce the activity of the nitrogen-regulated permeases Gap1p and Put4p, whereas mutations in LST8 impair the activities of a broader set of amino acid permeases. The LST8 gene encodes a protein composed of WD-repeats and has a close human homologue. The LST7 gene encodes a novel protein. Together, these data indicate that SEC13, LST4, LST7, and LST8 function in the regulated delivery of Gap1p to the cell surface, perhaps as components of a post-Golgi secretory-vesicle coat.

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