Tryptophan permease gene TAT2 confers high-pressure growth in Saccharomyces cerevisiae.
Hydrostatic pressure in the range of 15 to 25 MPa was found to cause arrest of the cell cycle in G(1) phase in an exponentially growing culture of Saccharomyces cerevisiae, whereas a pressure of 50 MPa did not. We found that a plasmid carrying the TAT2 gene, which encodes a high-affinity tryptophan permease, enabled the cells to grow under conditions of pressure in the range of 15 to 25 MPa. Additionally, cells expressing the Tat2 protein at high levels became endowed with the ability to grow under low-temperature conditions at 10 or 15 degrees C as well as at high pressure. Hydrostatic pressure significantly inhibited tryptophan uptake into the cells, and the Tat2 protein level was down-regulated by high pressure. The activation volume associated with tryptophan uptake was found to be a large positive value, 46.2 +/- 3.85 ml/mol, indicating that there was a net volume increase in a rate-limiting step in tryptophan import. The results showing cell cycle arrest in G(1) phase and down-regulation of the Tat2 protein seem to be similar to those observed upon treatment of cells with the immunosuppressive drug rapamycin. Although rapamycin treatment elicited the rapid dephosphorylation of Npr1 and induction of Gap1 expression, hydrostatic pressure did not affect the phosphorylation state of Npr1 and it decreased the level of Gap1 protein, suggesting that the pressure-sensing pathway may be independent of Npr1 function. Here we describe high-pressure sensing in yeast in comparison with the TOR-signaling pathway and discuss an important factor involved in adaptation of organisms to high-pressure environments.
Abe
F
F
The DEEPSTAR Group, Japan Marine Science and Technology Center, Yokosuka 237-0061, Japan. abef@jamstec.go.jp
Horikoshi
K
K
D026905:Amino Acid Transport Systems; D015153:Blotting, Western; D002453:Cell Cycle; D002455:Cell Division; D004262:DNA Restriction Enzymes / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D029968:Escherichia coli Proteins; D005434:Flow Cytometry; D005656:Fungal Proteins / Q000378:metabolism; D016193:G1 Phase; D006874:Hydrostatic Pressure; D007166:Immunosuppressive Agents / Q000494:pharmacology; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011494:Protein Kinases; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D015398:Signal Transduction; D020123:Sirolimus / Q000494:pharmacology; D013696:Temperature; D013816:Thermodynamics; D013997:Time Factors; D014364:Tryptophan / Q000493:pharmacokinetics; D020703:ras GTPase-Activating Proteins / Q000378:metabolism
D026905:Amino Acid Transport Systems; D029968:Escherichia coli Proteins; D005656:Fungal Proteins; C491145:GAP1 protein, S cerevisiae; D007166:Immunosuppressive Agents; D026901:Membrane Transport Proteins; D029701:Saccharomyces cerevisiae Proteins; C429825:TAT2 protein, S cerevisiae; D020703:ras GTPase-Activating Proteins; C066958:NPR1 protein, S cerevisiae; C035131:TnaB protein, E coli; D014364:Tryptophan; D011494:Protein Kinases; D004262:DNA Restriction Enzymes; D020123:Sirolimus