More than folding: localized functions of cytosolic chaperones.
Compared with other chaperone systems, heat shock proteins Hsp70 and Hsp90 interact with a larger variety of co-chaperone proteins that regulate their activity or aid in the folding of specific substrate proteins. Although many co-chaperones are soluble cytosolic proteins, co-chaperone domains are also found in modular adaptor proteins, which are often localized to intracellular membranes or elements of the cytoskeleton. These specialized co-chaperones include auxilin, cysteine string protein, Tom70, UNC-45 and homologs of Bag-1. The localized co-chaperones can harness the ATP-dependent mechanisms of Hsp70 and Hsp90 to do conformational work in diverse functional contexts, including vesicle secretion and recycling, protein transport and the regulated assembly and/or disassembly of protein complexes. Such flexibility is unique to the cytosolic Hsp70 and Hsp90 chaperone system.
Young
Jason C
JC
Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18a, D-82152, Martinsried, Germany. young@biochem.mpg.de
Barral
José M
JM
Ulrich Hartl
F
F
D000818:Animals; D034021:Auxilins / Q000378:metabolism; D002966:Clathrin / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary
D034021:Auxilins; D002966:Clathrin; D005656:Fungal Proteins; D018840:HSP70 Heat-Shock Proteins; D018841:HSP90 Heat-Shock Proteins; D008565:Membrane Proteins; D018832:Molecular Chaperones