Comparing the functional properties of the Hsp70 chaperones, DnaK and BiP.
The Hsp70 family of molecular chaperones is an essential class of chaperones that is present in many different cell types and cellular compartments. We have compared the bioactivities of the prokaryotic cytosolic Hsp70, DnaK, to that of the eukaryotic Hsp70, BiP, located in the endoplasmic reticulum (ER). Both chaperones helped to prevent protein aggregation. However, only DnaK provided enhanced refolding of denatured proteins. We also tested chaperone folding assistance during translation in the context of cell-free protein synthesis reactions for several protein targets and show that both DnaK and BiP can provide folding assistance under these conditions. Our results support previous reports suggesting that DnaK provides both post-translational and co-translational folding assistance while BiP predominantly provides folding assistance that is contemporaneous with translation.
Bonomo
Jeanne
J
Department of Chemical Engineering, Stanford University, 381 North-South Mall, Stanford, CA 94305-5025, USA. jeanne.bonomo@gmail.com
Welsh
John P
JP
Manthiram
Karthish
K
Swartz
James R
JR
D004721:Endoplasmic Reticulum / Q000378:metabolism; D000091342:Endoplasmic Reticulum Chaperone BiP; D029968:Escherichia coli Proteins / Q000737:chemistry*; D018840:HSP70 Heat-Shock Proteins / Q000737:chemistry*; D006360:Heat-Shock Proteins / Q000737:chemistry*; D008156:Luciferases / Q000737:chemistry; D014176:Protein Biosynthesis; D017510:Protein Folding; D017434:Protein Structure, Tertiary
D000091342:Endoplasmic Reticulum Chaperone BiP; D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D008156:Luciferases; C063842:dnaK protein, E coli