Protein quality control: triage by chaperones and proteases.

Gottesman, Susan; Wickner, Sue; Maurizi, Michael R.

doi:10.1101/gad.11.7.815

Cited by 514 publications

(433 citation statements)

References 70 publications

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“…Most stress-associated polypeptides, also called heat-shock proteins (Hsp) because they were first observed in cells exposed to elevated temperatures, are either molecular chaperones or energy-dependent proteases. The chaperones play crucial roles in promoting folding, stabilization, solubilization, renaturation and degradation of polypeptides, and also facilitate the transport of polypeptides into specific cellular compartments and the assembly of multiprotein complexes (Bukau & Horwich, 1998;Gottesman et al, 1997). The energy-dependent proteases perform targeted polypeptide degradation, modulating the availability of regulatory elements and removing non-functional but potentially harmful polypeptides that arise when polypeptides misfold, denature and/or aggregate (Gottesman, 1996).…”

Section: Introductionmentioning

confidence: 99%

Effects of high light on transcripts of stress-associated genes for the cyanobacteria Synechocystis sp. PCC 6803 and Prochlorococcus MED4 and MIT9313

Mary

Grossman

et al. 2004

Microbiology

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Cyanobacteria constitute an ancient, diverse and ecologically important bacterial group. The responses of these organisms to light and nutrient conditions are finely controlled, enabling the cells to survive a range of environmental conditions. In particular, it is important to understand how cyanobacteria acclimate to the absorption of excess excitation energy and how stress-associated transcripts accumulate following transfer of cells from low-to high-intensity light. In this study, quantitative RT-PCR was used to monitor changes in levels of transcripts encoding chaperones and stress-associated proteases in three cyanobacterial strains that inhabit different ecological niches: the freshwater strain Synechocystis sp. PCC 6803, the marine high-light-adapted strain Prochlorococcus MED4 and the marine low-light-adapted strain Prochlorococcus MIT9313. Levels of transcripts encoding stress-associated proteins were very sensitive to changes in light intensity in all of these organisms, although there were significant differences in the degree and kinetics of transcript accumulation. A specific set of genes that seemed to be associated with high-light adaptation (groEL/groES, dnaK2, dnaJ3, clpB1 and clpP1) could be targeted for more detailed studies in the future. Furthermore, the strongest responses were observed in Prochlorococcus MED4, a strain characteristic of the open ocean surface layer, where hsp genes could play a critical role in cell survival.

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Section: Introductionmentioning

confidence: 99%

Effects of high light on transcripts of stress-associated genes for the cyanobacteria Synechocystis sp. PCC 6803 and Prochlorococcus MED4 and MIT9313

Mary

Grossman

et al. 2004

Microbiology

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“…Gottesman et al (1997) have proposed a general model for handling misfolded proteins in vivo in which either swift refolding of proteins with functional potential is achieved or irreversibly denatured and damaged proteins are rapidly degraded. If this model is applied to type I R-M systems, on the assumption that HsdR subunits are the substrate for the ClpXP protease, a failure to stabilize an inactive polypeptide would lead to loss of restriction potential.…”

Section: Discussionmentioning

confidence: 99%

ClpX and ClpP are essential for the efficient acquisition of genes specifying type IA and IB restriction systems

Makovets

Titheradge

Murray

1998

Molecular Microbiology

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SummaryEfficient acquisition of genes that encode a restriction and modification (R-M) system with specificities different from any already present in the recipient bacterium requires the sequential production of the new modification enzyme followed by the restriction activity in order that the chromosome of the recipient bacterium is protected against attack by the restriction endonuclease. We show that ClpX and ClpP, the components of ClpXP protease, are necessary for the efficient transmission of the genes encoding EcoKI and EcoAI, representatives of two families of type I R-M systems, thus implicating ClpXP in the modulation of restriction activity. Loss of ClpX imposed a bigger barrier than loss of ClpP, consistent with a dual role for ClpX, possibly as a chaperone and as a component of the ClpXP protease. Transmission of genes specifying EcoKI was more dependent on ClpX and ClpP than transmission of the genes for EcoAI. Sensitivity to absence of the protease was also influenced by the mode of gene transfer; conjugative transfer and transformation were more dependent on ClpXP than transduction. In the absence of either ClpX or ClpP transfer of the EcoKI genes by P1-mediated transduction was impaired, transfer of the EcoAI genes was not.

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“…As the nature of the N-terminal amino acid of a protein is known to influence its degradation pathway (Varshavsky, 1996), such proteins would thus be tagged for destruction, to be completed by other proteases or by other protein-processing cellular machineries such as the proteasomes. Strikingly, a functional association between molecular chaperones and certain proteases has been described in both E. coli and mitochondria (Wawrzynow et al, 1995;Wagner et al, 1994), and it has been proposed that the proteases and the chaperones act in a co-ordinate way to determine the final fate of the cellular proteins (Gottesman et al, 1997).…”

Section: Discussionmentioning

confidence: 99%

A novel aminopeptidase associated with the 60 kDa chaperonin in the thermophilic archaeon Sulfolobus solfataricus

Condò

Ruggero

Reinhardt

et al. 1998

Molecular Microbiology

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SummaryThe chaperonins are high-molecular-weight protein complexes having a characteristic double-ring toroidal shape; they are thought to aid the folding of denatured or newly synthesized polypeptides. These proteins exist as two functionally similar but distantly related families, one including the bacterial and organellar chaperonins and the other (termed the CCT-TRiC family) including the chaperonins of the Archaea and the eukaryotes. The CCT-TRiC chaperonins, particularly their archeal members, are less well known than their bacterial counterparts, and their main cellular function is still doubtful. In this work, we report that the chaperonin of the thermophilic archaeon Sulfolobus solfataricus interacts with several polypeptides other than the two subunits that constitute the 18-mer double-ring structure. We have cloned and sequenced the gene encoding one 90 kDa chaperonin-associated protein and have shown, using biochemical assays, that the product is an enzyme belonging to the family of zinc-dependent aminopeptidases. The Sulfolobus protein shows maximal homology to eukaryotic (yeast and mouse) aminopeptidases. It contains a leucine zipper motif and can be phosphorylated by an unidentified kinase present in the cell extracts. The possible significance of an association between an aminopeptidase and a chaperonin is discussed.

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Protein quality control: triage by chaperones and proteases.

Cited by 514 publications

References 70 publications

Effects of high light on transcripts of stress-associated genes for the cyanobacteria Synechocystis sp. PCC 6803 and Prochlorococcus MED4 and MIT9313

Effects of high light on transcripts of stress-associated genes for the cyanobacteria Synechocystis sp. PCC 6803 and Prochlorococcus MED4 and MIT9313

ClpX and ClpP are essential for the efficient acquisition of genes specifying type IA and IB restriction systems

A novel aminopeptidase associated with the 60 kDa chaperonin in the thermophilic archaeon Sulfolobus solfataricus

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