Regulation and interconversion of the potassium transport systems of Saccharomyces cerevisiae as revealed by rubidium transport.
The kinetics of Rb+ transport in Saccharomyces cerevisiae depended on the K+ content of the cells and on K+ starvation, as follows. In cells with normal K+ (grown at millimolar K+), Rb+ transport was regulated by internal K+. The loss of K+ first decreased the Km and later increased the Vmax of Rb+ transport. K+ starvation of normal-K+ cells for 4-5 h decreased the Km of Rb+ transport below the minimum observed after K+ loss. During this time Eadie-Hofstee plots of Rb+ transport suggest that the existing system was converted into a new one with a higher affinity. Growth at 10 microM K+ only required the system triggered by K+ loss, and the system expressed in K+-starved cells was not expressed under these conditions.
D000255:Adenosine Triphosphate / Q000502:physiology; D000641:Ammonia / Q000494:pharmacology; D001692:Biological Transport; D004734:Energy Metabolism; D005656:Fungal Proteins / Q000096:biosynthesis; D011188:Potassium / Q000378:metabolism* / Q000502:physiology; D012413:Rubidium / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000254:growth & development / Q000378:metabolism*
D005656:Fungal Proteins; D000641:Ammonia; D000255:Adenosine Triphosphate; D012413:Rubidium; D011188:Potassium