Proteins interacting with the molecular chaperone hsp70/hsc70: physical associations and effects on refolding activity.
We investigated several hsp70/hsc70 interacting proteins and established by two independent techniques that hsp40 and Hop/p60 specifically interact with the 257 residue carboxy-terminal domain of hsp70 while Hap-46 and Hip/p48 bind the 383 residue amino-terminal ATP binding domain. Hap-46 and Hip/p48 competed for binding to hsc70, while Hap-46 had no effect on the binding of either Hop/p60 or hsp40 to hsc70. Hap-46 inhibited the refolding of thermally denatured firefly luciferase in an hsc70 and hsp40 dependent assay, and this effect was largely compensated by Hop/p60. These interacting proteins thus appear to cooperate in affecting the chaperoning activity of hsp70/hsc70.
Gebauer
M
M
Institut für Biologische Chemie, Universität Heidelberg, Germany. mgebauer@sun0.urz.uni-heidelberg.de
Zeiner
M
M
Gehring
U
U
D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D050883:HSC70 Heat-Shock Proteins; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins / Q000737:chemistry / Q000378:metabolism*; D006360:Heat-Shock Proteins / Q000737:chemistry / Q000378:metabolism; D006361:Heating; D006801:Humans; D008156:Luciferases / Q000378:metabolism; D018832:Molecular Chaperones / Q000737:chemistry / Q000378:metabolism*; D011489:Protein Denaturation; D017510:Protein Folding; D011506:Proteins / Q000737:chemistry / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D025521:Tumor Suppressor Proteins; D015003:Yeasts / Q000378:metabolism
D002352:Carrier Proteins; C494647:DNAJB1 protein, human; D050883:HSC70 Heat-Shock Proteins; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; C494371:HSPA8 protein, human; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D011506:Proteins; D011993:Recombinant Fusion Proteins; C101119:ST13 protein, human; C079373:STIP1 protein, human; D025521:Tumor Suppressor Proteins; D008156:Luciferases