Hsp70 chaperones: cellular functions and molecular mechanism.
Matthias P. Mayer,Bernd Bukau +1 more
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TLDR
This work has shown that for specific tasks the Hsp70 cycle is coupled to the action of other chaperones, such as Hsp90 and Hsp100, and this ATPase cycle is controlled by co-chaperones of the family of J-domain proteins, which target H Sp70s to their substrates, and by nucleotide exchange factors, which determine the lifetime of the HSp70-substrate complex.Abstract:
Hsp70 proteins are central components of the cellular network of molecular chaperones and folding catalysts. They assist a large variety of protein folding processes in the cell by transient association of their substrate binding domain with short hydrophobic peptide segments within their substrate proteins. The substrate binding and release cycle is driven by the switching of Hsp70 between the low-affinity ATP bound state and the high-affinity ADP bound state. Thus, ATP binding and hydrolysis are essential in vitro and in vivo for the chaperone activity of Hsp70 proteins. This ATPase cycle is controlled by co-chaperones of the family of J-domain proteins, which target Hsp70s to their substrates, and by nucleotide exchange factors, which determine the lifetime of the Hsp70-substrate complex. Additional co-chaperones fine-tune this chaperone cycle. For specific tasks the Hsp70 cycle is coupled to the action of other chaperones, such as Hsp90 and Hsp100.read more
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Gravitropism and mechanical signaling in plants
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Hsp90 Breaks the Deadlock of the Hsp70 Chaperone System.
TL;DR: It is shown that Hsp90 takes a key role in protein folding by breaking an Hsp70-inflicted folding block, empowering protein clients to fold on their own, and speculate that the decreasing hydrophobicity along the HSp70-Hsp90 cascade may be crucial for enabling spontaneous folding.
Journal ArticleDOI
The chloroplast HSP70B-CDJ2-CGE1 chaperones catalyse assembly and disassembly of VIPP1 oligomers in Chlamydomonas.
Cuimin Liu,Felix Willmund,Jochen R. Golecki,Sabrina Cacace,Barbara Hess,Christine Markert,Michael Schroda +6 more
TL;DR: In this paper, the authors analyzed the composition of VIPP1/chaperone complexes in Chlamydomonas reinhardtii cell extracts and monitored effects of the chaperones on VIPP 1 assembly states in vitro.
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A chloroplast-targeted DnaJ protein contributes to maintenance of photosystem II under chilling stress
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References
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Molecular Chaperones in the Cytosol: from Nascent Chain to Folded Protein
TL;DR: Understanding how the thousands of different proteins synthesized in a cell use this chaperone machinery has profound implications for biotechnology and medicine.
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Hsp90 as a capacitor for morphological evolution
TL;DR: It is reported that when Drosophila Hsp90 is mutant or pharmacologically impaired, phenotypic variation affecting nearly any adult structure is produced, with specific variants depending on the genetic background and occurring both in laboratory strains and in wild populations.
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Regulation of signaling protein function and trafficking by the hsp90/hsp70-based chaperone machinery.
William B. Pratt,David O. Toft +1 more
TL;DR: This purified system of five purified proteins should facilitate understanding of how eukaryotlc hsp70 and hsp90 work together as essential components of a process that alters the conformations of substrate proteins to states that respond in signal transduction.
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Invited Review: Heat shock proteins: modifying factors in physiological stress responses and acquired thermotolerance
TL;DR: Recent evidence and hypotheses suggesting that the HSPs may be important modifying factors in cellular responses to a variety of physiologically relevant conditions such as hyperthermia, exercise, oxidative stress, metabolic challenge, and aging are examined.
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Hsp104, Hsp70, and Hsp40: A Novel Chaperone System that Rescues Previously Aggregated Proteins
John R Glover,Susan Lindquist +1 more
TL;DR: It is concluded that Hsp104 has a protein remodeling activity that acts on trapped, aggregated proteins and requires specific interactions with conventional chaperones to promote refolding of the intermediates it produces.