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Yeast Trk1 Potassium Transporter Gradually Changes Its Affinity in Response to Both External and Internal Signals

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    0557979 - FGÚ 2023 RIV CH eng J - Článek v odborném periodiku
    Masaryk, Jakub - Sychrová, Hana
    Yeast Trk1 Potassium Transporter Gradually Changes Its Affinity in Response to Both External and Internal Signals.
    Journal of Fungi. Roč. 8, č. 5 (2022), č. článku 432. E-ISSN 2309-608X
    Grant CEP: GA ČR(CZ) GA20-04420S
    Institucionální podpora: RVO:67985823
    Klíčová slova: cation homeostasis * Saccharomyces cerevisiae * potassium uptake * membrane potential
    Obor OECD: Microbiology
    Impakt faktor: 5.724, rok: 2021
    Způsob publikování: Open access
    https://www.mdpi.com/2309-608X/8/5/432

    Yeasts need a high intracellular concentration of potassium to grow. The main K+ uptake system in Saccharomyces cerevisiae is the Trk1 transporter, a complex protein with four MPM helical membrane motifs. Trk1 has been shown to exist in low- or high-affinity modes, which reflect the availability of potassium in the environment. However, when and how the affinity changes, and whether the potassium availability is the only signal for the affinity switch, remains unknown. Here, we characterize the Trk1 kinetic parameters under various conditions and find that Trk1's K-T and V-max change gradually. This gliding adjustment is rapid and precisely reflects the changes in the intracellular potassium content and membrane potential. A detailed characterization of the specific mutations in the P-helices of the MPM segments reveals that the presence of proline in the P-helix of the second and third MPM domain (F820P and L949P) does not affect the function of Trk1 in general, but rather specifically prevents the transporter's transition to a high-affinity state. The analogous mutations in the two remaining MPM domains (L81P and L1115P) result in a mislocalized and inactive protein, highlighting the importance of the first and fourth P-helices in proper Trk1 folding and activity at the plasma membrane.
    Trvalý link: http://hdl.handle.net/11104/0331853

     
     
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