title: Vacuolar functions are involved in stress-protective effect of intracellular proline in Saccharomyces cerevisiae.
abstract: Proline protects yeast cells from damage caused by various stresses. A yeast Saccharomyces cerevisiae mutant with high levels of intracellular proline grown in a minimal medium accumulated proline in its vacuole, but when grown in a nutrient medium, accumulated proline mainly in the cytosol. To understand the role of the proline pool in the vacuole, we examined the stress-protective effect of proline in proline-accumulating yeast cells deficient in vacuolar functions. The disruption of PEP3 encoding a vacuolar membrane protein required for vacuolar biogenesis caused hypersensitivity to heat shock and ethanol stresses, probably due to disappearance of normal vacuoles. The vph1-disrupted cells lacking vacuolar-ATPase activity showed resistance to heat shock without any change in proline localization, but showed severe growth defects in an ethanol-containing medium. These results indicate that vacuolar functions are involved in the stress-protective effect of proline in S. cerevisiae. Also, it appears that excess proline is transported to the vacuole in an ATP-independent manner.
authors.affiliation: Department of Bioscience, Fukui Prefectural University, 4-1-1 Kenjojima, Fukui 910-1195, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Matsuura
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Takagi
mesh_terms: D033942:Adaptor Proteins, Vesicular Transport; D001693:Biological Transport, Active / Q000502:physiology; D006358:Hot Temperature; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D011392:Proline / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D025262:Vacuolar Proton-Translocating ATPases / Q000235:genetics / Q000378:metabolism*; D014617:Vacuoles / Q000201:enzymology* / Q000235:genetics
chemical_list: D033942:Adaptor Proteins, Vesicular Transport; D008565:Membrane Proteins; C071657:PEP3 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D011392:Proline; D025262:Vacuolar Proton-Translocating ATPases