The Golgi apparatus plays a significant role in the maintenance of Ca2+ homeostasis in the vps33Δ vacuolar biogenesis mutant of saccharomyces cerevisiae

Academic Article

Abstract

  • The vacuole is the major site of intracellular Ca2+ storage in yeast and functions to maintain cytosolic Ca2+ levels within a narrow physiological range. In this study, we examined how cellular Ca2+ homeostasis is maintained in a vps33Δ vacuolar biogenesis mutant. We found that growth of the vps33Δ strain was sensitive to high or low extracellular Ca2+. This strain could not properly regulate cytosolic Ca2+ levels and was able to retain only a small fraction of its total cellular Ca2+ in a nonexchangeable intracellular pool. Surprisingly, the vps33Δ strain contained more total cellular Ca2+ than the wild type strain. Because most cellular Ca2+ is normally found within the vacuole, this suggested that other intracellular compartments compensated for the reduced capacity to store Ca within the vacuole of this strain. To test this hypothesis, we examined the contribution of the Golgi-localized Ca2+ ATPase Pmr1p in the maintenance of cellular Ca2+ homeostasis. We found that a vps33Δ/pmr1Δ strain was hypersensitive to high extracellular Ca2+. In addition, certain combinations of mutations effecting both vacuolar and Golgi Ca2+ transport resulted in synthetic lethality. These results indicate that the Golgi apparatus plays a significant role in maintaining Ca2+ homeostasis when vacuolar biogenesis is compromised.
  • Published In

    Digital Object Identifier (doi)

    Pubmed Id

  • 10226580
  • Author List

  • Miseta A; Fu L; Kellermayer R; Buckley J; Bedwell DM
  • Start Page

  • 5939
  • End Page

  • 5947
  • Volume

  • 274
  • Issue

  • 9