Accumulation of α-ketoglutaric acid in yeast mutants requiring lysine

Bhattacharjee, J. K.; Tucci, Anthony F.; Strassman, Murray

doi:10.1016/0003-9861(68)90129-x

Cited by 18 publications

(13 citation statements)

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“…Homoaconitase converts homocitrate to homoisocitrate in the lysine biosynthesis pathway [9]. The orthologous gene encoding homoaconitase, LYS4 , in the model yeast Saccharomyces cerevisiae , is essential for lysine biosynthesis [10]. The protein encoded by S. cerevisiae LYS4 contains amino acid residues associated with an iron-sulfur (Fe–S) cluster and shows evolutionary conservation with the aconitase family of proteins [3,11].…”

Section: Introductionmentioning

confidence: 99%

The lysine biosynthetic enzyme Lys4 influences iron metabolism, mitochondrial function and virulence in Cryptococcus neoformans

Park

et al. 2016

Biochemical and Biophysical Research Communications

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The lysine biosynthesis pathway via α-aminoadipate in fungi is considered an attractive target for antifungal drugs due to its absence in mammalian hosts. The iron-sulfur cluster-containing enzyme homoaconitase converts homocitrate to homoisocitrate in the lysine biosynthetic pathway, and is encoded by LYS4 in the model yeast Saccharomyces cerevisiae. In this study, we identified the ortholog of LYS4 in the human fungal pathogen, Cryptococcus neoformans, and found that LYS4 expression is regulated by iron levels and by the iron-related transcription factors Hap3 and HapX. Deletion of the LYS4 gene resulted in lysine auxotrophy suggesting that Lys4 is essential for lysine biosynthesis. Our study also revealed that lysine uptake was mediated by two amino acid permeases, Aap2 and Aap3, and influenced by nitrogen catabolite repression (NCR). Furthermore, the lys4 mutant showed increased sensitivity to oxidative stress, agents that challenge cell wall/membrane integrity, and azole antifungal drugs. We showed that these phenotypes were due in part to impaired mitochondrial function as a result of LYS4 deletion, which we propose disrupts iron homeostasis in the organelle. The combination of defects are consistent with our observation that the lys4 mutant was attenuated virulence in a mouse inhalation model of cryptococcosis.

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Section: Introductionmentioning

confidence: 99%

The lysine biosynthetic enzyme Lys4 influences iron metabolism, mitochondrial function and virulence in Cryptococcus neoformans

Park

et al. 2016

Biochemical and Biophysical Research Communications

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“…Aconitase, the Fe-S enzyme A-aminoadipate, a downstream metabolite of the lysine biosyn-that catalyzes the isomerization of citrate to isocitrate in the thetic pathway, and because they accumulated in their culture Krebs cycle [55], may also be impaired. Thus, from our experimedia homocitrate and homocitrate plus homoaconitate, respec-mental results, we propose that Lys7p may act not in the general tively [26]. Here we show that lys7∆ yeast strains displayed, in Cu metabolism but more precisely in the pathway between Cu addition to lysine auxotrophy, numerous other phenotypes re-and Cu/Zn-SOD.…”

Section: -Bismentioning

confidence: 56%

“…The DISCUSSION respiratory competence of lys7∆ strains indicates the presence In S. cerevisiae, the LYS7 and LYS4 genes were originally of the intracellular Cu and Fe because cells unable to import Cu associated with the homocitrate dehydratation and homoaconi-(ctr1∆) or Fe (fet3∆) or unable to deliver Cu to the mitochondria tate hydratation, respectively, which are consecutive steps of the (cox17∆) are respiratory deficient [50,53]. Cytochrome-c oxilysine biosynthetic pathway [26]. These assignments rely on the dase, the terminal complex of mitochondrial and bacterial respifindings that the lys7 and the lys4 mutants were auxotrophs for ratory chains, is thought to be the key enzyme because it relysine and could grow when media was supplemented with quires Cu and Fe for activity [54].…”

Section: -Bismentioning

confidence: 99%

“…In contrast, no system is The S. cerevisiae LYS7 gene was proposed to encode the known to scavenge specifically OHᠨ, perhaps because of its very enzyme catalyzing the second step of the lysine biosynthetic short half-life. SOD are found in nearly all aerobic phyla and use pathway [26], but was then suspected of playing a pleiotropic transition metals as co-factors, the metal used varying between role and perhaps of acting outside of the lysine pathway [27, species and within species [16,17]. The yeast Saccharomyces 28].…”

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The Saccharomyces cerevisiae LYS7 gene is involved in oxidative stress protection

Gamonet

Lauquin

1998

European Journal of Biochemistry

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Saccharomyces cerevisiae Lys7p was proposed to be the enzyme catalyzing the dehydratation of homocitrate to cis-homoaconitate, the second step of the lysine biosynthetic pathway. In this communication we provide evidence that Lys7p is involved in oxidative stress protection. Cells deleted for the LYS7 gene displayed, in addition to lysine auxotrophy, methionine auxotrophy, sensitivity to superoxide generating drugs and light irradiation, and diminution of calcineurin activity. The SOD1 gene encoding the Cu/Zn-superoxide dismutase was expressed in strains lacking Lys7p, and although Sod1p was produced in normal amounts no detectable enzyme activity was found. In contrast, the mitochondrial Mn-superoxide dismutase activity did not seem to be impaired. lys7 cells exhibited a normal uptake of Cu from growth medium. The Cu/Zn-superoxide dismutase activity was restored by addition of Cu (but not by addition of other metallic cations) to the growth medium or to cellular extracts, suggesting a lack of Cu 2ϩ at the active site. These results render it necessary to reconsider the role of the Lys7p. Its involvement in Cu metabolism and oxidative-stress protection, and the possibility of a human equivalent in amyotrophic lateral sclerosis are discussed.Keywords : yeast ; lysine biosynthesis; superoxide dismutase ; copper; amyotrophic lateral sclerosis.Respiration and oxidative metabolism offer a fabulous ad-erating drugs [20]. In agreement with the possible involvement of Sod1p in Cu buffering [21], the production of Sod1p is vantage in energy utilization, but oxygen use is very dangerous. Natural reactions with oxygen lead to the production of reactive increased by Cu, this effect being mediated by Ace1p, a Cudependent transcription factor, which also regulates production oxygen species: hydrogen peroxide (H 2 O 2 ); superoxide anion (O Ϫ 2 ) and hydroxyl radical (OHᠨ) [1Ϫ4]. In cells, these highly of the main Cu-detoxicating protein Cup1p [22, 23]. In addition, expression of SOD1 is increased under low-glucose derepressing toxic radicals damage cellular components [5Ϫ7] and are implicated in various disorders, including hypertension, heart or ner-conditions and under hyperoxia [24]. Under anaerobic conditions the enzyme seems to be in the form of an apoprotein, vous-system diseases, and the aging process [8Ϫ13]. Aerobic life would not have developed without defenses against such which can be reactivated by the addition of Cu [25]. This suggests that the incorporation of Cu and Zn into the mature enreactive species. Three major scavenging systems have zyme does not necessarily take place during protein synthesis. emerged: catalase and glutathione peroxidase are involved in the Nothing is known about how Cu/Zn-SOD acquires its metallic destruction of H 2 O 2 , while superoxide dismutase (SOD) catacofactors, which are essential for the enzyme catalysis. lyzes the dismutation of O Ϫ 2 [14,15]. In contrast, no system is The S. cerevisiae LYS7 gene was proposed to encode the known to scavenge specifically OHᠨ, perhaps because o...

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“…Homoaconitase essentially contributes to the isomerization of homocitrate to homoisocitrate in the second step of the AAP pathway. Deletion of the homoaconitase-encoding genes, lysF or lys4, leads to lysine auxotrophy in Aspergillus species (Weidner et al, 1997;Liebmann et al, 2004) and S. cereviasiae (Strassman and Ceci, 1966;Bhattacharjee et al, 1968), respectively. In this paper we report the results of our studies on C. albicans LYS4 gene disruption and phenotypic characterization of the mutant obtained.…”

Section: Introductionmentioning

confidence: 99%

Phenotypic consequences of LYS4 gene disruption in Candida albicans

Gabriel

Kur

Laforce-Nesbitt

et al. 2014

Yeast

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A BLAST search of the Candida Genome Database with the Saccharomyces cerevisiae LYS4 sequence known to encode homoaconitase (HA) revealed ORFs 19.3846 and 19.11327. Both alleles of the LYS4 gene were sequentially disrupted in Candida albicans BWP17 cells using PCR-based methodology. The null lys4Δ mutant exhibited lysine auxotrophy in minimal medium but was able to grow in the presence of L-Lys and α-aminoadipate, an intermediate of the α-aminoadipate pathway, at millimolar concentrations. The presence of D-Lys and pipecolic acid did not trigger lys4Δ growth. The C. albicans lys4Δ mutant cells demonstrated diminished germination ability. However, their virulence in vivo in a murine model of disseminated neonatal candidiasis appeared identical to that of the wild-type strain. Moreover, there was no statistically significant difference in fungal burden of infected tissues between the strains.

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Accumulation of α-ketoglutaric acid in yeast mutants requiring lysine

Cited by 18 publications

References 8 publications

The lysine biosynthetic enzyme Lys4 influences iron metabolism, mitochondrial function and virulence in Cryptococcus neoformans

The lysine biosynthetic enzyme Lys4 influences iron metabolism, mitochondrial function and virulence in Cryptococcus neoformans

The Saccharomyces cerevisiae LYS7 gene is involved in oxidative stress protection

Phenotypic consequences of LYS4 gene disruption in Candida albicans

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