Quantitative determination of the intracellular concentration of the various forms of HPr, a phosphocarrier protein of the phosphoenolpyruvate: Sugar phosphotransferase system in growing cells of oral streptococci

Vadeboncoeur, Christian; Brochu, Denis; Reizer, Jonathan

doi:10.1016/0003-2697(91)90112-7

Cited by 46 publications

(80 citation statements)

References 15 publications

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“…The PEP-to-pyruvate ratio changes in response to the metabolic state of the cell. Starving cells have a high PEP-to-pyruvate ratio, and under resting conditions the PTS proteins are therefore mainly phosphorylated (28,30) and the cells are primed to take up any PTS substrate they might encounter. In metabolically active cells, the PEP-topyruvate ratio is low and the PTS proteins are barely phosphorylated at His and Cys residues (30).…”

Section: Pts-mediated Regulation By Phosphorylationmentioning

confidence: 99%

“…Starving cells have a high PEP-to-pyruvate ratio, and under resting conditions the PTS proteins are therefore mainly phosphorylated (28,30) and the cells are primed to take up any PTS substrate they might encounter. In metabolically active cells, the PEP-topyruvate ratio is low and the PTS proteins are barely phosphorylated at His and Cys residues (30). Very low phosphorylation of the PTS proteins is therefore usually observed in cells efficiently metabolizing PTS sugars, such as glucose (28,31).…”

Section: Pts-mediated Regulation By Phosphorylationmentioning

confidence: 99%

“…The kinase function of HprK/P is enhanced during growth on efficiently utilized carbon sources (30,35), and the resulting seryl-phosphorylated HPr (PSer-HPr) is a poor substrate for the PEP-dependent phosphorylation by PϳEI (36,37). This mechanism further lowers the poor PEP-requiring phosphorylation of HPr and the EIIA and EIIB components in firmicutes growing on an efficiently metabolizable carbon source.…”

Section: Pts-mediated Regulation By Phosphorylationmentioning

confidence: 99%

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The Bacterial Phosphoenolpyruvate:Carbohydrate Phosphotransferase System: Regulation by Protein Phosphorylation and Phosphorylation-Dependent Protein-Protein Interactions

Deutscher

Aké

Derkaoui

et al. 2014

Microbiol Mol Biol Rev

329

374

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SUMMARY The bacterial phosphoenolpyruvate (PEP):carbohydrate phosphotransferase system (PTS) carries out both catalytic and regulatory functions. It catalyzes the transport and phosphorylation of a variety of sugars and sugar derivatives but also carries out numerous regulatory functions related to carbon, nitrogen, and phosphate metabolism, to chemotaxis, to potassium transport, and to the virulence of certain pathogens. For these different regulatory processes, the signal is provided by the phosphorylation state of the PTS components, which varies according to the availability of PTS substrates and the metabolic state of the cell. PEP acts as phosphoryl donor for enzyme I (EI), which, together with HPr and one of several EIIA and EIIB pairs, forms a phosphorylation cascade which allows phosphorylation of the cognate carbohydrate bound to the membrane-spanning EIIC. HPr of firmicutes and numerous proteobacteria is also phosphorylated in an ATP-dependent reaction catalyzed by the bifunctional HPr kinase/phosphorylase. PTS-mediated regulatory mechanisms are based either on direct phosphorylation of the target protein or on phosphorylation-dependent interactions. For regulation by PTS-mediated phosphorylation, the target proteins either acquired a PTS domain by fusing it to their N or C termini or integrated a specific, conserved PTS regulation domain (PRD) or, alternatively, developed their own specific sites for PTS-mediated phosphorylation. Protein-protein interactions can occur with either phosphorylated or unphosphorylated PTS components and can either stimulate or inhibit the function of the target proteins. This large variety of signal transduction mechanisms allows the PTS to regulate numerous proteins and to form a vast regulatory network responding to the phosphorylation state of various PTS components.

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Section: Pts-mediated Regulation By Phosphorylationmentioning

confidence: 99%

Section: Pts-mediated Regulation By Phosphorylationmentioning

confidence: 99%

Section: Pts-mediated Regulation By Phosphorylationmentioning

confidence: 99%

See 1 more Smart Citation

The Bacterial Phosphoenolpyruvate:Carbohydrate Phosphotransferase System: Regulation by Protein Phosphorylation and Phosphorylation-Dependent Protein-Protein Interactions

Deutscher

Aké

Derkaoui

et al. 2014

Microbiol Mol Biol Rev

329

374

View full text Add to dashboard Cite

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“…The membrane was then washed three times with 10 mM Tris/HCl (pH 8.0) containing 150 mM NaC1, incubated with peroxidaseconjugated anti-rabbit immunoglobulin G for 60 min, and developed with 10 ml 0.3 YO 4-chloro-1-naphthol (Sigma) in cold methanol mixed with 50 ml 0.06% H,O, in Tris-saline (10 mM Tris/HCl, 0.9% NaC1, pH 7-4) (Hawkes, 1982). Crossed immunoelectrophoresis was conducted as described by Vadeboncoeur et al (1991a). Antiserum against HPr was obtained from female New Zealand White rabbits after immunization by multisite subcutaneous injection (Gauthier e t a/., 1984).…”

Section: Introductionmentioning

confidence: 99%

Surface location of HPr, a phosphocarrier of the phosphoenolpyruvate: sugar phosphotransferase system in Streptococcus suis

et al. 1996

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HPr is a low-molecular-mass phosphocarrier protein of the bacterial phosphoenolpyruvate (PEP) :sugar phosphotransferase system (PTS) found in the cytoplasm or associated with the inner surface of the cytoplasmic membrane. Treatment of Streptococcus suis cells with a SorvaII Omnimixer, a technique used to extract cell surface components, resulted in the extraction of a major protein with a molecular mass of 9 kDa. Several lines of evidence suggested that this protein was HPr: (i) the 5. suis protein showed homology over the first 35 N-terminal amino acid residues with the HPrs of Streptococcus salivarius and Streptococcus mutans, including the signature sequence for the site of PEP-dependent phosphorylation; (ii) it cross-reacted with the 5. salivarius anti-HPr antibody preparation; (iii) it could be phosphorylated by enzyme I at the expense of PEP, and by a membrane-associated kinase a t the expense of ATP; and (iv) it possessed phosphocarrier activity when used as a source of HPr in an in vitro PTS assay. The data suggested that a portion of the cellular HPr is associated with the external cell surface in S. suis, a result that was confirmed by immunogold electron microscopy. The cellular HPr of 5. suis consisted of two forms that could be distinguished by the presence or the absence of the N-terminal methionine. Amino acid sequence analysis indicated that the cell-surface-associated HPr of S. suis lacked the N-terminal methionine residue.

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“…Previous work has already demonstrated that cellular levels of HPr in streptococci vary two-to threefold with culture conditions and that the relative proportions of the different forms of HPr also change with respect to growth rate (14,36,43,44). However, we do not know to what extent these variations alter the capacity of HPr to fulfill its functions.…”

mentioning

confidence: 99%

Diversity of Streptococcus salivarius ptsH Mutants That Can Be Isolated in the Presence of 2-Deoxyglucose and Galactose and Characterization of Two Mutants Synthesizing Reduced Levels of HPr, a Phosphocarrier of the Phosphoenolpyruvate:Sugar Phosphotransferase System

2001

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In streptococci, HPr, a phosphocarrier of the phosphoenolpyruvate:sugar phosphotransferase transport system (PTS), undergoes multiple posttranslational chemical modifications resulting in the formation of HPr(HisϳP), HPr(Ser-P), and HPr(Ser-P)(HisϳP), whose cellular concentrations vary with growth conditions. Distinct physiological functions are associated with specific forms of HPr. We do not know, however, the cellular thresholds below which these forms become unable to fulfill their functions and to what extent modifications in the cellular concentrations of the different forms of HPr modify cellular physiology. In this study, we present a glimpse of the diversity of Streptococcus salivarius ptsH mutants that can be isolated by positive selection on a solid medium containing 2-deoxyglucose and galactose and identify 13 amino acids that are essential for HPr to properly accomplish its physiological functions. We also report the characterization of two S. salivarius mutants that produced approximately two-and threefoldless HPr and enzyme I (EI) respectively. The data indicated that (i) a reduction in the synthesis of HPr due to a mutation in the Shine-Dalgarno sequence of ptsH reduced ptsI expression; (ii) a threefold reduction in EI and HPr cellular levels did not affect PTS transport capacity; (iii) a twofold reduction in HPr synthesis was sufficient to reduce the rate at which cells metabolized PTS sugars, increase generation times on PTS sugars and to a lesser extent on non-PTS sugars, and impede the exclusion of non-PTS sugars by PTS sugars; (iv) a threefold reduction in HPr synthesis caused a strong derepression of the genes coding for ␣-galactosidase, ␤-galactosidase, and galactokinase when the cells were grown at the expense of a PTS sugar but did not affect the synthesis of ␣-galactosidase when cells were grown at the expense of lactose, a noninducing non-PTS sugar; and (v) no correlation was found between the magnitude of enzyme derepression and the cellular levels of HPr(Ser-P).Histidine-containing protein, heat-stable protein, and heteromorphous protein are all epithets that have been used to designate HPr, the bacterial phosphocarrier of the phosphoenolpyruvate:sugar phosphotransferase transport system (PTS) (19,41). Results obtained over the past decade unequivocally indicate that the qualifier "heterofunctional protein" also applies to this small, approximately 9-kDa protein (27,31,35).The PTS is a multienzyme complex that sequentially catalyzes the transport and phosphorylation of sugars (27, 32) and plays a cardinal role in regulatory processes that allow bacteria to metabolize sugars differently depending on environmental conditions (31,33,35,45). The HPr of gram-positive bacteria can be phosphorylated on His15 at the expense of phosphoenolpyruvate by enzyme I (EI) of the PTS and on Ser46 by the ATP-dependent HPr(Ser) kinase-phosphatase (HPrK) (27,31,33,35,45). HPr(HisϳP) not only is involved in sugar transport but also controls transcription of several genes by transferring its phosphate grou...

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Quantitative determination of the intracellular concentration of the various forms of HPr, a phosphocarrier protein of the phosphoenolpyruvate: Sugar phosphotransferase system in growing cells of oral streptococci

Cited by 46 publications

References 15 publications

The Bacterial Phosphoenolpyruvate:Carbohydrate Phosphotransferase System: Regulation by Protein Phosphorylation and Phosphorylation-Dependent Protein-Protein Interactions

The Bacterial Phosphoenolpyruvate:Carbohydrate Phosphotransferase System: Regulation by Protein Phosphorylation and Phosphorylation-Dependent Protein-Protein Interactions

Surface location of HPr, a phosphocarrier of the phosphoenolpyruvate: sugar phosphotransferase system in Streptococcus suis

Diversity of Streptococcus salivarius ptsH Mutants That Can Be Isolated in the Presence of 2-Deoxyglucose and Galactose and Characterization of Two Mutants Synthesizing Reduced Levels of HPr, a Phosphocarrier of the Phosphoenolpyruvate:Sugar Phosphotransferase System

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