The vacuole as the lysosome of the yeast cell

Matile, Philippe; Wiemken, A.

doi:10.1007/bf00408765

Cited by 239 publications

(71 citation statements)

References 21 publications

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“…Presumably, the large vesicles were derived from the vacuolar system of the fungus, which is known to become more abundant in older hyphae (Buller, 1933;Grove et al, 1970). The proteases in these vacuoles (Matile & Wiemken, 1967;Schwencke et al, 1983) may be responsible for the marked loss of chitin synthetase activity from stationary-phase mycelium during sucrose density gradient fractionation.…”

Section: Discussionmentioning

confidence: 99%

Chitosomes and chitin synthetase in the asexual life cycle of Mucor rouxii: spores, mycelium and yeast cells

Kamada

Bracker²,

Bartnicki-García³

1991

Journal of General Microbiology

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To help understand the subcellular machinery responsible for cell wall formation in a fungus, we determined the abundance and subcellular distribution of chitin synthetase (chitin synthase, EC 2.4.1.16) and chitosomes in the asexual life cycle of Mucor rouxii. Cell-free extracts of ungerminated sporangiospores, hyphaelmycelium in exponential and stationary phase, and yeast cells were fractionated by isopycnic centrifugation in sucrose density gradients. The total amount of chitin synthetase per cell increased exponentially during aerobic germination of spores. In all developmental stages, the profile of chitin synthetase activity encompassed a broad range of sucrose density (d = 1.12-1.22) with two distinct zones: a low-density chitosome zone (d = approx. 1.12-1.16) and a highdensity, mixed-membrane zone (d = approx. 1.16-1.22). Chitosomes were a major reservoir of chitin synthetase in all stages of the life cycle, including ungerminated spores. Two kinds of chitin synthetase profiles were recognized and correlated with the growth state. In nongrowing cells (ungerminated sporangiospores and stationary-phase mycelium), the profile was skewed toward lower densities with a sharp chitosome peak at d = 1.12-1.13. In actively growing cultures (aerobic mycelium or anaerobic yeast cells), the entire profile of chitin synthetase was displaced toward higher densities; the average buoyant density of chitosomes was higher (d= 1-14-1.16), and more chitin synthetase was associated with denser (d= 1.16-1.23) membrane fractions. In all life cycle stages, chitosomal chitin synthetase was almost completely zymogenic. In contrast to the enzyme from spores or from growing cells, samples of chitosomal chitin synthetase from stationary-phase mycelium were unstable and contained a high proportion of larger vesicles in addition to the typical microvesicles. The presence of chitosomes in ungerminated spores indicates that these cells are poised to begin synthesizing somatic (= vegetative) cell walls at the onset of germination. The increased buoyant density of chitosomes in actively growing cultures suggests that the composition of these microvesicles changes significantly as they mobilize chitin synthetase to the cell surface.

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Section: Discussionmentioning

confidence: 99%

Chitosomes and chitin synthetase in the asexual life cycle of Mucor rouxii: spores, mycelium and yeast cells

Kamada

Bracker²,

Bartnicki-García³

1991

Journal of General Microbiology

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“…Both inhibitors were found in the soluble fraction of a metabolic lysate from spheroplasts. The other proteinase inhibitors known at present from yeast have also been reported to be localized in the extravacuolar cytosol [32,33] whereas the respective proteinases are present in the vacuoles [35]. A protective function against proteolytic damage within the cytoplasm has been discussed for the already described proteinase inhibitors from yeast [l, 33,43, 441.…”

Section: Discussionmentioning

confidence: 99%

“…The proteinase B inhibitor IB2 from Saccharomyces cerevisiae had been shown to be localized in the cytoplasm [32,33] whereas proteinase B was found in the vacuoles of the yeast cell [6,34,35]. For the subcellular localization of the proteinase B inhibitors from Saccharomyces carlsbergensis a metabolic lysate from spheroplasts according to Indge [36], containing intact vacuoles, was fractionated by centrifugation at 40 000 x g in a supernatant and a sedimenting fraction.…”

Section: Subcellular Localizationmentioning

confidence: 99%

Isolation, Characterization and Localization of the Proteinase B Inhibitor IB3 from Saccharomyces carlsbergensis

1979

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A heat-stable polypeptide has been detected in Saccharomyces carlsbergensis which inhibits specifically proteinase B from yeast. This proteinase B inhibitor 1'3 differs substantially in chemical, physical and antigenic properties from the earlier described proteinase B inhibitors IBl and 1'2 from yeast. The inhibitor 1'3 has been purified from S. carlsbergensis and appears to be homogeneous by disc gel electrophoresis and sodium dodecyl sulfate gel electrophoresis. The molecular weight has been estimated at 11 500, with no evidence for the existence of subunits. The amino acid analysis shows the absence of tryptophan. No compounds other than amino acids could be detected. The isoelectric point is 4.6. The inhibitor is not affected by incubation with proteinase B but is inactivated by proteinase A and carboxypeptidase Y from yeast and by trypsin from bovine pancreas. The proteinase B inhibitor association constant was calculated to be 3.3 x lo9 M-' and the enzyme inhibitor complex is stable at 25°C in the pH range 5-10. The inhibitor does not exhibit immunological cross-reactivity with IB1 and 1'2. After centrifugal fractionation at 40000 x g of a metabolic lysate from spheroplasts the inhibitor was found to be localized in the supernatant, i.e. the extravacuolar soluble fraction.

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“…Several intracellular proteolytic enzymes have been found in Saccharomyces cerevisiae 95,98 : two endoproteinases, proteinase A 2,20,21,62,69 and B 20,34,58 , two carboxypeptidases, carboxypeptidase Y and carboxypeptidase S 107 , several aminopeptidases 66,67 , and one dipeptidase 25 . The two main vacuolar endopeptidases yscA and yscB are essential for protein degradation during vegetative growth and under starvation con-ditions 74,80,101,106,108 .…”

Section: Intracellular Proteinase Activitymentioning

confidence: 99%

“…The two main vacuolar endopeptidases yscA and yscB are essential for protein degradation during vegetative growth and under starvation con-ditions 74,80,101,106,108 . Although non-specific proteolysis of endocytosed proteins such as membrane receptors or extracellular proteins is largely confined to the lysosomal/ vacuolar system 22,55,56,61,66,67 proteolysis also takes place in other cell compartments. The staining procedure was conducted according to Hutter et al 46 with casein substrates labelled with quenched BODIPY ® FL dye, which is a substituted 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene derivative 35,53 .…”

Section: Intracellular Proteinase Activitymentioning

confidence: 99%

The Potential of Confocal Imaging for Measuring Physiological Changes in Brewer's Yeast

Schlee

Miedl

Leiper

et al. 2006

Journal of the Institute of Brewing

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This study focused on the implementation of fluorescence optical methods and laser scanning confocal microscopy for monitoring brewing yeast performance. Physiological parameters and cell compounds in yeast cells (glycogen, neutral lipids, trehalose, bud scars, DNA and intracellular proteinases) have been successfully visualised with the aid of highly specific fluorochromes. The expression and sub cellular localisation of proteinase A during fermentation has been studied employing a Saccharomyces cerevisiae green fluorescent protein clone. This novel approach to monitoring brewing yeast performance provides new insights into physiological events that occur during wort fermentation.

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The vacuole as the lysosome of the yeast cell

Cited by 239 publications

References 21 publications

Chitosomes and chitin synthetase in the asexual life cycle of Mucor rouxii: spores, mycelium and yeast cells

Chitosomes and chitin synthetase in the asexual life cycle of Mucor rouxii: spores, mycelium and yeast cells

Isolation, Characterization and Localization of the Proteinase B Inhibitor IB3 from Saccharomyces carlsbergensis

The Potential of Confocal Imaging for Measuring Physiological Changes in Brewer's Yeast

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