Effects of Abnormal-Sterol Accumulation on
            <i>Ustilago maydis</i>
            Plasma Membrane H
            <sup>+</sup>
            -ATPase Stoichiometry and Polypeptide Pattern

Hernández, Agustín; Cooke, David T.; Clarkson, David T.

doi:10.1128/jb.180.2.412-415.1998

Cited by 5 publications

(7 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In our case, activation of H + -ATPase activity did not involve changes in affinity for substrate, pH optimum or sensitivity to vanadate, but exhibits changes in the V max of the protein, thus differing from glucose-induced activation. As stated before, we showed that polypeptide amounts of H + -ATPase showed no changes upon EBI fungicide treatment or in the mutants [18]. On the other hand, this activation showed particular characteristics, namely, it is nonessential, and involves changes in the V max of the protein but other factors remain mostly unchanged.…”

Section: Discussionsupporting

confidence: 68%

“…It could be argued that this activation may be due to other causes such as increased polypeptide amounts in membrane or changes in fluidity. We have shown previously that these two factors remain largely unchanged in the same conditions used in this study [18,21].…”

Section: Discussionsupporting

confidence: 68%

“…The reason for this discrepancy is unknown but maybe due to species variation. It is noteworthy that U. maydis H + -ATPase is a slightly larger enzyme than that of Saccaromyces cerevisiae [18]. In our hands, erythrosin B fitted a mixed mechanism of inhibition.…”

Section: Discussionsupporting

confidence: 46%

“…Glucose-induced activation of yeast plasma membrane H + -ATPase shows characteristic changes in kinetic parameters such as pH optimum, K m for MgATP and K i for vanadate. Although we found no glucose-induced activation of ATPase activity [18] we tested whether the activation observed in these mutants and EBI-treated strains showed any similarities in its changes in kinetic parameters. Optimum pH was determined over a range of 2.5 pH units from 5.5 to 8.0.…”

Section: R E S U L T Smentioning

confidence: 88%

“…Indeed, growth retardation in abnormal sterol-accumulating U. maydis is accompanied by changes in the linoleic/oleic acid ratio of complex lipid-bound (CLB)-fatty acids and increases in plasma membrane H + -ATPase activity [21]. However, no changes in membrane fluidity, permeability to protons or amounts of H + -ATPase polypeptide were observed [18,21]. In the present report, we show that a change in the 18 : 2/18 : 1 ratio is responsible for a promotion of ATP hydrolytic activity in U. maydis plasma membrane H + -ATPase upon disturbance of the normal membrane sterol profile.…”

mentioning

confidence: 99%

See 4 more Smart Citations

In vivo activation of plasma membrane H⁺‐ATPase hydrolytic activity by complex lipid‐bound unsaturated fatty acids in Ustilago maydis

Hernández

Cooke

Clarkson

2002

European Journal of Biochemistry

Self Cite

View full text Add to dashboard Cite

As an adaptation process to the growth retardation provoked by the presence of nonlethal concentrations of ergosterol biosynthesis inhibitors, Ustilago maydis alters the ratio of linoleic to oleic acid bound to plasma membrane complex lipids [Hernández, A., Cooke, D.T., Lewis, M. & Clarkson, D.T. (1997) Microbiology143, 3165–3174]. This alteration increases plasma membrane H+‐ATPase hydrolytic activity. Activation of H+‐ATPase by the linoleic/oleic acid proportion is noncompetitive, nonessential and only involves changes in the maximum velocity of the pump. Optimum pH, affinity to MgATP and constants for the inhibition by vanadate and erythrosin B remain unchanged. This all indicates that activation of plasma membrane H+‐ATPase by unsaturated fatty acids differs clearly from glucose‐induced activation observed in yeast. Also, it is a physiologically relevant event similar to other, as yet uncharacterized, changes in plasma membrane H+‐ATPase hydrolytic activity observed in plants and fungi, as part of an adaptation process to different stress conditions.

show abstract

Section: Discussionsupporting

confidence: 68%

Section: Discussionsupporting

confidence: 68%

Section: Discussionsupporting

confidence: 46%

Section: R E S U L T Smentioning

confidence: 88%

mentioning

confidence: 99%

See 3 more Smart Citations

In vivo activation of plasma membrane H⁺‐ATPase hydrolytic activity by complex lipid‐bound unsaturated fatty acids in Ustilago maydis

Hernández

Cooke

Clarkson

2002

European Journal of Biochemistry

Self Cite

View full text Add to dashboard Cite

show abstract

8-Dehydrosterols induce membrane traffic and autophagy defects through V-ATPase dysfunction in Saccharomyces cerevisae

Hernández¹,

Serrano-Bueno²,

Perez-Castiñeira³

et al. 2015

Biochimica et Biophysica Acta (BBA) - Molecular Cell Research

View full text Add to dashboard Cite

8-Dehydrosterols are present in a wide range of biologically relevant situations, from human rare diseases to amine fungicide-treated fungi and crops. However, the molecular bases of their toxicity are still obscure. We show here that 8-dehydrosterols, but not other sterols, affect yeast vacuole acidification through V-ATPases. Moreover, erg2Δ cells display reductions in proton pumping rates consistent with ion-transport uncoupling in vitro. Concomitantly, subunit Vph1p shows conformational changes in the presence of 8-dehydrosterols. Expression of a plant vacuolar H(+)-pumping pyrophosphatase as an alternative H(+)-pump relieves Vma(-)-like phenotypes in erg2Δ-derived mutant cells. As a consequence of these acidification defects, endo- and exo-cytic traffic deficiencies that can be alleviated with a H(+)-pumping pyrophosphatase are also observed. Despite their effect on membrane traffic, 8-dehydrosterols do not induce endoplasmic reticulum stress or assembly defects on the V-ATPase. Autophagy is a V-ATPase dependent process and erg2Δ mutants accumulate autophagic bodies under nitrogen starvation similar to Vma(-) mutants. In contrast to classical Atg(-) mutants, this defect is not accompanied by impairment of traffic through the CVT pathway, processing of Pho8Δ60p, GFP-Atg8p localisation or difficulties to survive under nitrogen starvation conditions, but it is concomitant to reduced vacuolar protease activity. All in all, erg2Δ cells are autophagy mutants albeit some of their phenotypic features differ from classical Atg(-) defective cells. These results may pave the way to understand the aetiology of sterol-related diseases, the cytotoxic effect of amine fungicides, and may explain the tolerance to these compounds observed in plants.

show abstract

Abnormal sterol-induced cell wall glucan deficiency in yeast is due to impaired glucan synthase transport to the plasma membrane

Gutierrez-Armijos

Sussmann

Silber

et al. 2020

Biochemical Journal

View full text Add to dashboard Cite

Abnormal sterols disrupt cellular functions through yet unclear mechanisms. In Saccharomyces cerevisiae, accumulation of Δ8-sterols, the same type of sterols observed in patients of Conradi-Hünermann-Happle syndrome or in fungi after amine fungicide treatment, leads to cell wall weakness. We have studied the influence of Δ8-sterols on the activity of glucan synthase I, the protein synthetizing the main polymer in fungal cell walls, its regulation by the Cell Wall Integrity (CWI) pathway, and its transport from the endoplasmic reticulum to the plasma membrane. We ascertained that the catalytic characteristics were mostly unaffected by the presence of abnormal sterols but the enzyme was partially retained in the endoplasmic reticulum, leading to glucan deficit at the cell wall. Furthermore, we observed that glucan synthase I traveled through an unconventional exocytic route to the plasma membrane that is associated with low density intracellular membranes. Also, we found out that the CWI pathway remained inactive despite low glucan levels at the cell wall. Taken together, these data suggest that Δ8-sterols affect cell walls by inhibiting unconventional secretion of proteins leading to retention and degradation of glucan synthase I, while the compensatory CWI pathway is unable to activate. These results could be instrumental to understand defects of bone development in cholesterol biosynthesis disorders and fungicide mechanisms of action.

show abstract

Effects of Abnormal-Sterol Accumulation on Ustilago maydis Plasma Membrane H ⁺ -ATPase Stoichiometry and Polypeptide Pattern

Cited by 5 publications

References 22 publications

In vivo activation of plasma membrane H⁺‐ATPase hydrolytic activity by complex lipid‐bound unsaturated fatty acids in Ustilago maydis

In vivo activation of plasma membrane H⁺‐ATPase hydrolytic activity by complex lipid‐bound unsaturated fatty acids in Ustilago maydis

8-Dehydrosterols induce membrane traffic and autophagy defects through V-ATPase dysfunction in Saccharomyces cerevisae

Abnormal sterol-induced cell wall glucan deficiency in yeast is due to impaired glucan synthase transport to the plasma membrane

Contact Info

Product

Resources

About

Effects of Abnormal-Sterol Accumulation on Ustilago maydis Plasma Membrane H + -ATPase Stoichiometry and Polypeptide Pattern

Cited by 5 publications

References 22 publications

In vivo activation of plasma membrane H+‐ATPase hydrolytic activity by complex lipid‐bound unsaturated fatty acids in Ustilago maydis

In vivo activation of plasma membrane H+‐ATPase hydrolytic activity by complex lipid‐bound unsaturated fatty acids in Ustilago maydis

8-Dehydrosterols induce membrane traffic and autophagy defects through V-ATPase dysfunction in Saccharomyces cerevisae

Abnormal sterol-induced cell wall glucan deficiency in yeast is due to impaired glucan synthase transport to the plasma membrane

Contact Info

Product

Resources

About

Effects of Abnormal-Sterol Accumulation on Ustilago maydis Plasma Membrane H ⁺ -ATPase Stoichiometry and Polypeptide Pattern

In vivo activation of plasma membrane H⁺‐ATPase hydrolytic activity by complex lipid‐bound unsaturated fatty acids in Ustilago maydis

In vivo activation of plasma membrane H⁺‐ATPase hydrolytic activity by complex lipid‐bound unsaturated fatty acids in Ustilago maydis