Inhibition of Hsp70 ATPase activity and protein renaturation by a novel Hsp70-binding protein

Deborah A. Raynes, Vincent Guerriero

Research output: Contribution to journalArticle

89 Citations (Scopus)

Abstract

A cDNA that codes for an Hsp70-interacting protein (HspBP1) was isolated from a human heart cDNA library using the yeast two-hybrid system. The derived amino acid sequence is unique and therefore represents a new regulator of Hsp70. Northern blots of RNA from human tissues indicate that HspBP1 mRNA has a size of approximately 1.7 kilobase pairs and is present in all tissues analyzed but is most abundant in heart and skeletal muscle. Western blot analysis revealed a protein of approximately 40 kilodaltons detected in cell extracts. The ATPase domain of Hsp70 demonstrated binding to HspBP1. Further experiments showed binding of HspBP1 to Hsp70 and Hse70 in a total heart extract. HspBP1 (8 μM) inhibited approximately 90% of the Hsp40- activated Hsp70 ATPase activity. HspBP1 prevented ATP binding to Hsp70, and therefore this is the likely mechanism of inhibition. Hsp40-activated ATPase activity is essential for the renaturation activity of Hsp70; therefore, the effects of HspBP1 on renaturation of luciferase in a reticulocyte lysate and a defined system were examined. HspBP1 inhibited renaturation with half- maximal inhibition at 2 μM. These data indicate that we have identified a novel Hsp70-interacting protein that inhibits Hsp70 chaperone activity.

Original languageEnglish (US)
Pages (from-to)32883-32888
Number of pages6
JournalJournal of Biological Chemistry
Volume273
Issue number49
DOIs
StatePublished - Dec 4 1998

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Protein Renaturation
Adenosine Triphosphatases
Carrier Proteins
Tissue
Two-Hybrid System Techniques
Proteins
Reticulocytes
Cell Extracts
Luciferases
Hybrid systems
Gene Library
Northern Blotting
Yeast
Muscle
Amino Acid Sequence
Myocardium
Skeletal Muscle
Complementary DNA
Adenosine Triphosphate
Western Blotting

ASJC Scopus subject areas

  • Biochemistry

Cite this

Inhibition of Hsp70 ATPase activity and protein renaturation by a novel Hsp70-binding protein. / Raynes, Deborah A.; Guerriero, Vincent.

In: Journal of Biological Chemistry, Vol. 273, No. 49, 04.12.1998, p. 32883-32888.

Research output: Contribution to journalArticle

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