The Implication of YggT of<i>Escherichia coli</i>in Osmotic Regulation

Ito, Tomokazu; Uozumi, Nobuyuki; Nakamura, Tatsunosuke; Takayama, Sayuri; Matsuda, Nobuyuki; Aiba, Hirofumi; Hemmi, Hisashi; Yoshimura, Teizo

doi:10.1271/bbb.90558

Cited by 29 publications

(23 citation statements)

References 14 publications

(28 reference statements)

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“…The proportion of CL is increased in E. coli grown in medium with high osmolarity adjusted with either an ionic or a nonionic osmoticum, demonstrating that the range of osmolarity rather than the chemical nature of the osmoticum is important for up-regulation of CL biosynthesis (27). All mutant combinations were radiolabeled in medium containing 5 g/L NaCl and 0.6 M mannitol (28) and analyzed for lipid composition by 2D TLC at midlog phase (Table S2, row M*); WT cells and all mutant combinations except ΔclsABC showed increased CL when grown in high (M*) versus low (M) osmolarity medium. In high osmolarity medium, mutants expressing only clsA, clsC, or clsB showed 12%, 2.6%, or 0.3% CL, respectively.…”

Section: Resultsmentioning

confidence: 99%

Discovery of a cardiolipin synthase utilizing phosphatidylethanolamine and phosphatidylglycerol as substrates

Tan

Bogdanov²,

Zhao

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

207

321

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Depending on growth phase and culture conditions, cardiolipin (CL) makes up 5-15% of the phospholipids in Escherichia coli with the remainder being primarily phosphatidylethanolamine (PE) and phosphatidylglycerol (PG). In E. coli, the cls and ybhO genes (renamed clsA and clsB, respectively) each encode a CL synthase (Cls) that catalyzes the condensation of two PG molecules to form CL and glycerol. However, a ΔclsAB mutant still makes CL in the stationary phase, indicating the existence of additional Cls. We identified a third Cls encoded by ymdC (renamed clsC). ClsC has sequence homology with ClsA and ClsB, which all belong to the phospholipase D superfamily. The ΔclsABC mutant lacks detectible CL regardless of growth phase or growth conditions. CL can be restored to near wild-type levels in stationary phase in the triple mutant by expressing either clsA or clsB. Expression of clsC alone resulted in a low level of CL in the stationary phase, which increased to near wild-type levels by coexpression of its neighboring gene, ymdB. CL synthesis by all Cls is increased with increasing medium osmolarity during logarithmic growth and in stationary phase. However, only ClsA contributes detectible levels of CL at low osmolarity during logarithmic growth. Mutation of the putative catalytic motif of ClsC prevents CL formation. Unlike eukaryotic Cls (that use PG and CDP-diacylglycerol as substrates) or ClsA, the combined YmdB-ClsC used PE as the phosphatidyl donor to PG to form CL, which demonstrates a third and unique mode for CL synthesis.cardiolipin-deficient | bacteria | mass spectrometry

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Section: Resultsmentioning

confidence: 99%

Discovery of a cardiolipin synthase utilizing phosphatidylethanolamine and phosphatidylglycerol as substrates

Tan

Bogdanov²,

Zhao

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

207

321

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“…In the E. coli genome, yggS is located at 66.67 min on the genetic map and is in a polycistronic operon that is composed of 5 poorly characterized genes, yggS-yggT-yggU-yggV-yggW (1). A similar genetic localization is also found in the genomes of Salmonella enterica serovar Typhimurium, Klebsiella pneumoniae, and Pantoea sp.…”

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confidence: 79%

“…Gene knockout was verified through colony-directed PCR. Construction of pUS (pUC19-yggS) and pUSm has been described previously (1). A control plasmid, pU0, which contains part of the yggS sequence, was obtained by FspI digestion of pUS and then self-ligation (1).…”

Section: Methodsmentioning

confidence: 99%

“…Among the products of these operons, YggT is an integral membrane protein that has no clearly defined function, and its orthologs are found in bacteria and plants. We previously found that the introduction of the plasmid-borne yggT into an E. coli TK2420 strain, which lacks 3 major K ϩ uptake systems (Kdp, Trk, and Kup) and requires exogenous K ϩ , enabled us to restore cell growth at high osmotic pressure (1). The YggT homologs are required for the biogenesis of the c= heme in the cytochrome b 6 f complex in Chlamydomonas reinhardtii (2), as well as for the proper distribution of nucleoids in chloroplasts and cyanobacteria (3).…”

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confidence: 99%

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Conserved Pyridoxal Protein That Regulates Ile and Val Metabolism

et al. 2013

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Escherichia coli YggS is a member of the highly conserved uncharacterized protein family that binds pyridoxal 5=-phosphate (PLP). To assist with the functional assignment of the YggS family, in vivo and in vitro analyses were performed using a yggSdeficient E. coli strain (⌬yggS) and a purified form of YggS, respectively. In the stationary phase, the ⌬yggS strain exhibited a completely different intracellular pool of amino acids and produced a significant amount of L-Val in the culture medium. The log-phase ⌬yggS strain accumulated 2-ketobutyrate, its aminated compound 2-aminobutyrate, and, to a lesser extent, L-Val. It also exhibited a 1.3-to 2.6-fold increase in the levels of Ile and Val metabolic enzymes. The fact that similar phenotypes were induced in wild-type E. coli by the exogenous addition of 2-ketobutyrate and 2-aminobutyrate indicates that the 2 compounds contribute to the ⌬yggS phenotypes. We showed that the initial cause of the keto acid imbalance was the reduced availability of coenzyme A (CoA); supplementation with pantothenate, which is a CoA precursor, fully reversed phenotypes conferred by the yggS mutation. The plasmid-borne expression of YggS and orthologs from Bacillus subtilis, Saccharomyces cerevisiae, and humans fully rescued the ⌬yggS phenotypes. Expression of a mutant YggS lacking PLP-binding ability, however, did not reverse the ⌬yggS phenotypes. These results demonstrate for the first time that YggS controls Ile and Val metabolism by modulating 2-ketobutyrate and CoA availability. Its function depends on PLP, and it is highly conserved in a wide range species, from bacteria to humans.

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“…In light of the information presented above, it is likely that a pstB mutation impacts the lipid composition of P. aeruginosa so as to enhance CM perturbation by aminoglycosidegenerated mistranslated polypeptides. PA0392 has no known function at present, though its homologue in E. coli, YggT (36.7% amino acid identity), appears to play a role in osmotic stress tolerance (42). Given the impact of a PA0392 deletion on aminoglycoside-dependent CM perturbation and reports that membrane PL and FA changes occur in response to osmotic stress in several bacteria and may contribute to osmotic stress tolerance (70), PA0392 may well influence the CM lipid composition in ways that stabilize this structure, contributing to aminoglycoside resistance and, perhaps, tolerance to osmotic stress.…”

Section: Discussionmentioning

confidence: 99%

Determinants of Intrinsic Aminoglycoside Resistance in Pseudomonas aeruginosa

Krahn

Gilmour

Tilak

et al. 2012

Antimicrob Agents Chemother

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Screening of a transposon insertion mutant library of Pseudomonas aeruginosa for increased susceptibility to paromomycin identified a number of genes whose disruption enhanced susceptibility of this organism to multiple aminoglycosides, including tobramycin, amikacin, and gentamicin. These included genes associated with lipid biosynthesis or metabolism (lptA, faoA), phosphate uptake (pstB), and two-component regulators (amgRS, PA2797-PA2798) and a gene of unknown function (PA0392). Deletion mutants lacking these showed enhanced panaminoglycoside susceptibility that was reversed by the cloned genes, confirming their contribution to intrinsic panaminoglycoside resistance. None of these mutants showed increased aminoglycoside permeation of the cell envelope, indicating that increased susceptibility was not related to enhanced aminoglycoside uptake owing to a reduced envelope barrier function. Several mutants (pstB, faoA, PA0392, amgR) did, however, show increased cytoplasmic membrane depolarization relative to wild type following gentamicin exposure, consistent with the membranes of these mutants being more prone to perturbation, likely by gentamicin-generated mistranslated polypeptides. Mutants lacking any two of these resistance genes in various combinations invariably showed increased aminoglycoside susceptibility relative to single-deletion mutants, confirming their independent contribution to resistance and highlighting the complexity of the intrinsic aminoglycoside resistome in P. aeruginosa. Deletion of these genes also compromised the high-level panaminoglycoside resistance of clinical isolates, emphasizing their important contribution to acquired resistance.

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The Implication of YggT ofEscherichia coliin Osmotic Regulation

Cited by 29 publications

References 14 publications

Discovery of a cardiolipin synthase utilizing phosphatidylethanolamine and phosphatidylglycerol as substrates

Discovery of a cardiolipin synthase utilizing phosphatidylethanolamine and phosphatidylglycerol as substrates

Conserved Pyridoxal Protein That Regulates Ile and Val Metabolism

Determinants of Intrinsic Aminoglycoside Resistance in Pseudomonas aeruginosa

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