Degradation versus Aggregation of Misfolded Maltose-binding Protein in the Periplasm of Escherichia coli

Betton, Jean‐Michel; Sassoon, Nathalie; Hofnung, Maurice; Laurent, Michel

doi:10.1074/jbc.273.15.8897

Cited by 50 publications

(56 citation statements)

References 30 publications

(43 reference statements)

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“…Residual activation of s E may be the result of the production s E activation by C-source shifts of MalE, the extracytoplasmic maltose-binding protein/ receptor required for maltose utilization, as well as other maltodextrin-utilization proteins that are also expressed under these conditions (Hall et al, 1997). A previous study in E. coli found that at lower levels of expression a foldingdefective MalE protein is degraded by DegP or Protease III (Betton et al, 1998), supporting this idea. Unfortunately, knocking-out a required utilization component, such as MalE, would prevent growth on the C-source, and would again mimic C-starvation.…”

Section: Results and Disccusionsupporting

confidence: 62%

Shifts from glucose to certain secondary carbon-sources result in activation of the extracytoplasmic function sigma factor σ E in Salmonella enterica serovar Typhimurium

et al. 2005

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Salmonella enterica serovar Typhimurium (S. Typhimurium) elicits the starvation-stress response (SSR) due to starvation for an essential nutrient, e.g. a carbon/energy source (C-source). As part of the SSR, the alternative sigma factor s E is activated and induced. The authors suspect that this activation is, in part, triggered by changes in the S. Typhimurium cell envelope occurring during the adaptation from growth to carbon/energy starvation (C-starvation), and resulting in an increased need for s E -regulated factors involved in the proper folding and assembly of newly synthesized proteins destined for this extracytoplasmic compartment. This led to the hypothesis that a s E activation signal might arise during C-source shifts that cause the induction of proteins localized to the extracytoplasmic compartment, i.e. the outer membrane or periplasm, of the cell. To test this hypothesis, cultures were grown in minimal medium containing enough glucose to reach mid-exponential-phase, plus a non-limiting amount of a secondary 'less-preferred' but utilizable carbon/energy source. The s E activity was then monitored using plasmids carrying rpoEP1-and rpoEP2-lacZ transcriptional fusions, which exhibit s E -independent and -dependent lacZ expression, respectively. The secondary C-sources maltose, succinate and citrate, which have extracytoplasmic components involved in their utilization (e.g. LamB), resulted in a discernible diauxic lag period and a sustained increase in s E activity. Growth transition from glucose to other utilizable phosphotransferase (PTS) and non-PTS C-sources, such as trehalose, mannose, mannitol, fructose, glycerol, D-galactose or L-arabinose, did not cause a discernible diauxic lag period or a sustained increase in s E activity. Interestingly, a shift from glucose to melibiose, which does not use an extracytoplasmic-localized protein for uptake, did cause an observable diauxic lag period but did not result in a sustained increase in s E activity. In addition, overexpression of LamB from an arabinose-inducible promoter leads to a significant increase in s E activity in the absence of a glucose to maltose shift or C-starvation. Furthermore, a DlamB : : V-Km r mutant, lacking the LamB maltoporin, exhibited an approximately twofold reduction in the sustained s E activity observed during a glucose to maltose shift, again supporting the hypothesis. Interestingly, the LamB protein lacks the typical Y-X-F terminal tripeptide of the OmpC-like peptides that activate DegS protease activity leading to s E activation. It does, however, possess a terminal pentapeptide (Q-M-E-I-W-W) that may function as a ligand for a putative class II PDZ-binding site. The authors therefore propose that the s E regulon of S. Typhimurium not only is induced in response to deleterious environmental conditions, but also plays a role in the adaptation of cells to new growth conditions that necessitate changes in the extracytoplasmic compartment of the cell, which may involve alternative signal recognition and activation pathways t...

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Section: Results and Disccusionsupporting

confidence: 62%

Shifts from glucose to certain secondary carbon-sources result in activation of the extracytoplasmic function sigma factor σ E in Salmonella enterica serovar Typhimurium

et al. 2005

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“…The physiological role of Protease III is not known (Dykstra & Kushner, 1985;Swamy & Goldberg, 1982). It is thought that Protease III is involved in the turnover of proteins in the periplasmic space (Baneyx & Georgiou, 1991;Betton et al, 1998;Cornista et al, 2004). Thus, increased levels of Protease III may be needed after envelope stress.…”

Section: Members Of the S E Regulon Specific For S Typhimuriummentioning

confidence: 99%

Identification of the σ E regulon of Salmonella enterica serovar Typhimurium

et al. 2006

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The extracytoplasmic function sigma factor, s E , has been shown to play a critical role in virulence of Salmonella enterica serovar Typhimurium (S. Typhimurium). The previously optimized two-plasmid system has been used to identify S. Typhimurium promoters recognized by RNA polymerase containing s E . This method allowed identification of 34 s E -dependent promoters that direct expression of 62 genes in S. Typhimurium, 23 of which (including several specific for S. Typhimurium) have not been identified previously to be dependent upon s E in Escherichia coli. The promoters were confirmed in S. Typhimurium and transcriptional start points of the promoters were determined by S1-nuclease mapping. All the promoters contained sequences highly similar to the consensus sequence of s E -dependent promoters. The identified genes belonging to the S.Typhimurium s E -regulon encode proteins involved in primary metabolism, DNA repair systems and outer-membrane biogenesis, and regulatory proteins, periplasmic proteases and folding factors, proposed lipoproteins, and inner-and outer-membrane proteins with unknown functions. Several of these s E -dependent genes have been shown to play a role in virulence of S. Typhimurium.

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“…coli K12 strains pop6590 and pop6499, which are both derivatives of MC4100 (Betton et al, 1998), were used as host strain for phenotype characterizations and protein production, respectively. Both strains carry the nonpolar deletion of the chromosomal malE gene, AmalE444 (Shuman, 1982), and pop6499 harbors the malTC' allele, which confers constitutive and high-level expression on the maltose operons (Debarbouille et al, 1978).…”

Section: Bacterial Struins and Plasmidsmentioning

confidence: 99%

Tertiary structure‐dependence of misfolding substitutions in loops of the maltose‐binding protein

Raffy¹,

Sassoon²,

Hofnung³

et al. 1998

Protein Science

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We previously identified and characterized amino acid substitutions in a loop connecting helix I to strand B, the aI/pB loop, of the N-domain that are critical for in vivo folding of the maltose-binding protein (MalE31). The tertiary context-dependence of this mutation in MalE folding was assessed by probing the tolerance of an equivalent ap loop of the C-domain to the same amino acid substitutions (MaIE219). Moving the loop mutation from the N-to the C-domain eliminated the in vivo misfolding step that led to the formation of inclusion bodies. In vitro, both loop variants exhibited an important decrease of stability, but their intrinsic tendency to aggregate was well correlated with their periplasmic fates in Escherichia coli. Furthermore, the noncoincidence of the unfolding and refolding transition curves and increase of light scattering during the refolding of MalE31 indicate that a competing off-pathway reaction could occurs on the folding pathway of this variant. These results strongly support the notion that the formation of supersecondary structures of the N-domain is a rate-limiting step in the folding pathway of MalE.

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Degradation versus Aggregation of Misfolded Maltose-binding Protein in the Periplasm of Escherichia coli

Cited by 50 publications

References 30 publications

Shifts from glucose to certain secondary carbon-sources result in activation of the extracytoplasmic function sigma factor σ E in Salmonella enterica serovar Typhimurium

Shifts from glucose to certain secondary carbon-sources result in activation of the extracytoplasmic function sigma factor σ E in Salmonella enterica serovar Typhimurium

Identification of the σ E regulon of Salmonella enterica serovar Typhimurium

Tertiary structure‐dependence of misfolding substitutions in loops of the maltose‐binding protein

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