Key Role for Intracellular K+ and Protein Kinases Sat4/Hal4 and Hal5 in the Plasma Membrane Stabilization of Yeast Nutrient Transporters
- 1 August 2007
- journal article
- Published by Taylor & Francis Ltd in Molecular and Cellular Biology
- Vol. 27 (16), 5725-5736
- https://doi.org/10.1128/mcb.01375-06
Abstract
K+ transport in living cells must be tightly controlled because it affects basic physiological parameters such as turgor, membrane potential, ionic strength, and pH. In yeast, the major high-affinity K+ transporter, Trk1, is inhibited by high intracellular K+ levels and positively regulated by two redundant "halotolerance" protein kinases, Sat4/Hal4 and Hal5. Here we show that these kinases are not required for Trk1 activity; rather, they stabilize the transporter at the plasma membrane under low K+ conditions, preventing its endocytosis and vacuolar degradation. High concentrations (0.2 M) of K+, but not Na+ or sorbitol, transported by undefined low-affinity systems, maintain Trk1 at the plasma membrane in the hal4 hal5 mutant. Other nutrient transporters, such as Can1 (arginine permease), Fur4 (uracil permease), and Hxt1 (low-affinity glucose permease), are also destabilized in the hal4 hal5 mutant under low K+ conditions and, in the case of Can1, are stabilized by high K+ concentrations. Other plasma membrane proteins such as Pma1 (H+ -pumping ATPase) and Sur7 (an eisosomal protein) are not regulated by halotolerance kinases or by high K+ levels. This novel regulatory mechanism of nutrient transporters may participate in the quiescence/growth transition and could result from effects of intracellular K+ and halotolerance kinases on membrane trafficking and/or on the transporters themselves.Keywords
This publication has 47 references indexed in Scilit:
- Membrane potential governs lateral segregation of plasma membrane proteins and lipids in yeastThe EMBO Journal, 2006
- Eisosomes mark static sites of endocytosisNature, 2006
- Response of Fission Yeast to Toxic Cations Involves Cooperative Action of the Stress-Activated Protein Kinase Spc1/Sty1 and the Hal4 Protein KinaseMolecular and Cellular Biology, 2005
- NPR1 Kinase and RSP5-BUL1/2 Ubiquitin Ligase Control GLN3-dependent Transcription in Saccharomyces cerevisiaeOnline Journal of Public Health Informatics, 2004
- Visualization of Protein Compartmentation within the Plasma Membrane of Living Yeast CellsMolecular Biology of the Cell, 2003
- The Npr1 Kinase Controls Biosynthetic and Endocytic Sorting of the Yeast Gap1 PermeaseOnline Journal of Public Health Informatics, 2001
- Potassium transport in fungi and plantsBiochimica et Biophysica Acta (BBA) - Reviews on Biomembranes, 2000
- Epitope mapping and accessibility of immunodominant regions of yeast plasma membrane H+‐ATPaseJBIC Journal of Biological Inorganic Chemistry, 1993
- Study of the Positive Control of the General Amino‐Acid Permease and Other Ammonia‐Sensitive Uptake Systems by the Product of the NPR1 Gene in the Yeast Saccharomyces cerevisiaeJBIC Journal of Biological Inorganic Chemistry, 1983
- Ion Transport in yeastBiochimica et Biophysica Acta (BBA) - Reviews on Biomembranes, 1981