Nejvíce citovaný článek - PubMed ID 31346773
Trk1, the sole potassium-specific transporter in Candida glabrata, contributes to the proper functioning of various cell processes
The non-conventional yeast Kluyveromyces marxianus has recently emerged as a promising candidate for many food, environment, and biotechnology applications. This yeast is thermotolerant and has robust growth under many adverse conditions. Here, we show that its ability to grow under potassium-limiting conditions is much better than that of Saccharomyces cerevisiae, suggesting a very efficient and high-affinity potassium uptake system(s) in this species. The K. marxianus genome contains two genes for putative potassium transporters: KmHAK1 and KmTRK1. To characterize the products of the two genes, we constructed single and double knock-out mutants in K. marxianus and also expressed both genes in an S. cerevisiae mutant, that lacks potassium importers. Our results in K. marxianus and S. cerevisiae revealed that both genes encode efficient high-affinity potassium transporters, contributing to potassium homeostasis and maintaining plasma-membrane potential and cytosolic pH. In K. marxianus, the presence of HAK1 supports growth at low K+ much better than that of TRK1, probably because the substrate affinity of KmHak1 is about 10-fold higher than that of KmTrk1, and its expression is induced ~80-fold upon potassium starvation. KmHak1 is crucial for salt stress survival in both K. marxianus and S. cerevisiae. In co-expression experiments with ScTrk1 and ScTrk2, its robustness contributes to an increased tolerance of S. cerevisiae cells to sodium and lithium salt stress.
- Klíčová slova
- Kluyveromyces marxianu, K+–H+ symporter, affinity, potassium, transporter, uniporter,
- MeSH
- draslík * metabolismus MeSH
- fungální proteiny genetika metabolismus MeSH
- genový knockout MeSH
- Kluyveromyces * genetika metabolismus růst a vývoj MeSH
- koncentrace vodíkových iontů MeSH
- membránové potenciály MeSH
- proteiny přenášející kationty * genetika metabolismus MeSH
- regulace genové exprese u hub MeSH
- Saccharomyces cerevisiae * genetika metabolismus růst a vývoj MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- draslík * MeSH
- fungální proteiny MeSH
- proteiny přenášející kationty * MeSH
