title: Hsp70 chaperones: cellular functions and molecular mechanism.
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.
authors.affiliation: Zentrum für Molekulare Biologie (ZMBH), Universität Heidelberg, Im Neuenheimer Feld 282, 69120, Heidelberg, Germany. M.Mayer@zmbh.uni-heidelberg.de
authors.forename: M P
authors.initials: MP
authors.lastname: Mayer
authors.forename: B
authors.initials: B
authors.lastname: Bukau
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D001665:Binding Sites; D002352:Carrier Proteins / Q000378:metabolism; D002468:Cell Physiological Phenomena; D004268:DNA-Binding Proteins; D018840:HSP70 Heat-Shock Proteins / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000378:metabolism; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D014157:Transcription Factors; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism
chemical_list: C091732:BCL2-associated athanogene 1 protein; D001426:Bacterial Proteins; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D018840:HSP70 Heat-Shock Proteins; C105426:Hip chaperone; D018832:Molecular Chaperones; D014157:Transcription Factors; D044767:Ubiquitin-Protein Ligases; D000251:Adenosine Triphosphatases