The yeast potassium transporter TRK2 is able to substitute for TRK1 in its biological function under low K and low pH conditions
| Autor: | Carlos Lozano, Antonio Peña, Bertha Michel, Miriam Aide Castillo Rodríguez, Jorge Ramírez, Roberto Coria |
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| Rok vydání: | 2006 |
| Předmět: |
Saccharomyces cerevisiae Proteins
Potassium Heterologous chemistry.chemical_element Bioengineering Saccharomyces cerevisiae Biology Applied Microbiology and Biotechnology Biochemistry Polymerase Chain Reaction Histone Deacetylases Chlorides Genetics Northern blot RNA Messenger DNA Fungal Psychological repression Cation Transport Proteins Derepression Ion Transport Transporter Hydrogen-Ion Concentration Blotting Northern Rubidium Yeast Repressor Proteins Mutagenesis Insertional chemistry Membrane protein Rubidium Radioisotopes Gene Deletion Biotechnology Transcription Factors |
| Zdroj: | Yeast (Chichester, England). 23(8) |
| ISSN: | 0749-503X |
| Popis: | In S. cerevisiae, K+ transport relies principally on two structurally related membrane proteins, known as Trk1p and Trk2p. Direct involvement in cation movements has been demonstrated for Trk1p, which is a high-affinity K+ transporter. Initially described as a low-affinity K+ transporter, Trk2p seems to play a minor role in K+ transport, since its activity is only apparent under very specific conditions, such as in a Δsin3 background. Here we show that growth of a Δtrk1Δsin3 double mutant, under K+-limiting conditions or at low pH, is Trk2p-dependent, and by Northern blot analysis we demonstrate that deletion of SIN3 results in transcriptional derepression of TRK2. In addition, we show that heterologous overexpression of TRK2 with the inducible GAL1 promoter bypasses Sin3p repression in a Δtrk1Δtrk2 double mutant and fully restores growth under non-permissive conditions. Furthermore, kinetic experiments in a Δtrk1Δsin3 double mutant revealed a K+ transporter with an apparent high affinity and a moderate capacity. Taken together, these results indicate that TRK2 encodes a functional K+ transporter that, under our experimental conditions, displays distinctive kinetic characteristics. Copyright © 2006 John Wiley & Sons, Ltd. |
| Databáze: | OpenAIRE |
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