Hsp33 Controls Elongation Factor-Tu Stability and Allows Escherichia coli Growth in the Absence of the Major DnaK and Trigger Factor Chaperones

Bruel, Nicolas; Castanié-Cornet, Marie-Pierre; Cirinesi, Anne Marie; Koningstein, Gregory M.; Georgopoulos, Costa; Luirink, Joen; Genevaux, Pierre

doi:10.1074/jbc.m112.418525

Cited by 27 publications

(21 citation statements)

References 65 publications

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“…Because of Lon's intrinsic ability to recognize many substrates, we suspect that additional regulatory proteins promoting growth and cell cycle progression are also degraded upon protein unfolding stress. Indeed, loss of the DnaK chaperone in E. coli also appears to trigger Lon to degrade the translation elongation factor-Tu (Bruel et al, 2012). …”

Section: Discussionmentioning

confidence: 99%

Proteotoxic Stress Induces a Cell-Cycle Arrest by Stimulating Lon to Degrade the Replication Initiator DnaA

Jonas

Liu

Chien

et al. 2013

Cell

149

213

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Summary The decision to initiate DNA replication is a critical step in the cell cycle of all organisms. Cells often delay replication in the face of stressful conditions, but the underlying mechanisms remain incompletely defined. Here, we demonstrate in Caulobacter crescentus that proteotoxic stress induces a cell cycle arrest by triggering the degradation of DnaA, the conserved replication initiator. A depletion of available Hsp70 chaperone, DnaK, either through genetic manipulation or heat shock, induces synthesis of the Lon protease, which can directly degrade DnaA. Unexpectedly, we find that unfolded proteins, which accumulate following a loss of DnaK, also allosterically activate Lon to degrade DnaA, thereby ensuring a cell cycle arrest. Our work reveals a new mechanism for regulating DNA replication under adverse growth conditions. Additionally, our data indicate that unfolded proteins can actively and directly alter substrate recognition by cellular proteases.

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Section: Discussionmentioning

confidence: 99%

Proteotoxic Stress Induces a Cell-Cycle Arrest by Stimulating Lon to Degrade the Replication Initiator DnaA

Jonas

Liu

Chien

et al. 2013

Cell

149

213

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“…Indeed, a recently conducted study in E. coli reported that overexpression of Hsp33 rescued the synthetically lethal phenotype of a strain lacking the canonical chaperones trigger factor (TF) and DnaK [38]. The study suggested that Hsp33, by sequestering the essential elongation factor-Tu (EF-TU) for degradation to the Lon protease, slows down de novo protein synthesis, alleviating the need for TF and DnaK.…”

Section: Hsp33: a Paradigm For Stress-activated Chaperonesmentioning

confidence: 99%

Stress-Activated Chaperones: A First Line of Defense

Voth

Jakob

2017

Trends in Biochemical Sciences

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Proteins are constantly challenged by environmental stress conditions that threaten their structure and function. Especially problematic are oxidative, acid, or severe heat stress, which induce very rapid and widespread protein unfolding and generate conditions that make canonical chaperones and/or transcriptional responses inadequate to protect the proteome. Here, we review recent advances in identifying and characterizing stress-activated chaperones, which are inactive under non-stress conditions but become potent chaperones under specific protein-unfolding stress conditions. We discuss the posttranslational mechanisms by which these chaperones sense stress and consider the role intrinsic disorder plays in their regulation and function. We examine their physiological roles under both non-stress and stress conditions, their integration into the cellular proteostasis network, and their potential as novel therapeutic targets.

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“…As Lon and the chaperone machinery are widely distributed among bacteria, regulated DnaA degradation by Lon may be a broad mechanism for inducing growth arrest during stress. Intriguingly, there is an additional example of Lon targeting proliferation proteins for degradation: In E. coli that have lost the Hsp70 chaperone machine (Δ dnaKJ ), Hsp33 (HslO) can interact with the ribosomal elongation factor Tu (Ef-Tu) and target it for degradation by Lon, thereby inhibiting translation of proteins and leading to growth arrest [188]. …”

Section: Regulatory Proteolysis In Stress Responsementioning

confidence: 99%

Stress-Induced Remodeling of the Bacterial Proteome

Guo

Gross

2014

Current Biology

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Microorganisms live in fluctuating environments, requiring stress response pathways to resist environmental insults and stress. These pathways dynamically monitor cellular status, and mediate adaptive changes by remodeling the proteome, largely accomplished by remodeling transcriptional networks and protein degradation. The complementarity of fast, specific proteolytic degradation and slower, broad transcriptomic changes gives cells the mechanistic repertoire to dynamically adjust cellular processes and optimize response behavior. Together, this enables cells to minimize the “cost” of the response while maximizing the ability to survive environmental stress. Here we highlight recent progress in the understanding of transcriptional networks and proteolysis that illustrates design principles used by bacteria to generate the complex behaviors required to resist stress.

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Hsp33 Controls Elongation Factor-Tu Stability and Allows Escherichia coli Growth in the Absence of the Major DnaK and Trigger Factor Chaperones

Cited by 27 publications

References 65 publications

Proteotoxic Stress Induces a Cell-Cycle Arrest by Stimulating Lon to Degrade the Replication Initiator DnaA

Proteotoxic Stress Induces a Cell-Cycle Arrest by Stimulating Lon to Degrade the Replication Initiator DnaA

Stress-Activated Chaperones: A First Line of Defense

Stress-Induced Remodeling of the Bacterial Proteome

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