Domain Mapping of Heat Shock Protein 70 Reveals That Glutamic Acid 446 and Arginine 447 Are Critical for Regulating Superoxide Dismutase 2 Function
Autor: | Adeleye J. Afolayan, Maxwell Alexander, Ru-Jeng Teng, Girija G. Konduri, Teresa Michalkiewicz, Sara Zemanovic, Rebecca L Holme, Ujala Rana, Kirkwood A. Pritchard, Daisy Sahoo |
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Rok vydání: | 2017 |
Předmět: |
0301 basic medicine
Arginine Glutamic Acid Biology Biochemistry 03 medical and health sciences 0302 clinical medicine Superoxides Animals HSP70 Heat-Shock Proteins Asparagine Binding site skin and connective tissue diseases Molecular Biology Peptide sequence Cells Cultured Alanine chemistry.chemical_classification Binding Sites Sheep Superoxide Dismutase Cell Biology Glutamic acid Mitochondria Rats Amino acid Glutamine 030104 developmental biology Amino Acid Substitution chemistry 030220 oncology & carcinogenesis cardiovascular system Developmental Biology |
Zdroj: | Journal of Biological Chemistry. 292:2369-2378 |
ISSN: | 0021-9258 |
Popis: | Stress-inducible heat shock protein 70 (hsp70) interacts with superoxide dismutase 2 (SOD2) in the cytosol after synthesis to transfer the enzyme to the mitochondria for subsequent activation. However, the structural basis for this interaction remains to be defined. To map the SOD2-binding site in hsp70, mutants of hsp70 were made and tested for their ability to bind SOD2. These studies showed that SOD2 binds in the amino acid 393–537 region of the chaperone. To map the hsp70-binding site in SOD2, we used a series of pulldown assays and showed that hsp70 binds to the amino-terminal domain of SOD2. To better define the binding site, we used a series of decoy peptides derived from the primary amino acid sequence in the SOD2-binding site in hsp70. This study shows that SOD2 specifically binds to hsp70 at 445GERAMT450. Small peptides containing GERAMT inhibited the transfer of SOD2 to the mitochondria and decreased SOD2 activity in vitro and in vivo. To determine the amino acid residues in hsp70 that are critical for SOD2 interactions, we substituted each amino acid residue for alanine or more conservative residues, glutamine or asparagine, in the GERAMT-binding site. Substitutions of E446A/Q and R447A/Q inhibited the ability of the GERAMT peptide to bind SOD2 and preserved SOD2 function more than other substitutions. Together, these findings indicate that the GERAMT sequence is critical for hsp70-mediated regulation of SOD2 and that Glu446 and Arg447 cooperate with other amino acid residues in the GERAMT-binding site for proper chaperone-dependent regulation of SOD2 antioxidant function. |
Databáze: | OpenAIRE |
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