JCB logo
PeproTech: Cell Culture Supplements
  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents
This Article
Right arrow Full Text
Right arrow Full Text (PDF, 445K)
Right arrow PPT slides of all figures
Right arrow Alert me when this article is cited
Right arrow Citation Map
Services
Right arrow Email this article
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new content in the JCB
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Obermann, W. M.J.
Right arrow Articles by Hartl, F. U.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Obermann, W. M.J.
Right arrow Articles by Hartl, F. U.
Right arrowPubmed/NCBI databases
*Gene*GEO Profiles
*HomoloGene*Protein
*Structure*UniGene
*Compound via MeSH
*Substance via MeSH
Hazardous Substances DB
*MAGNESIUM COMPOUNDS
*MAGNESIUM, ELEMENTAL
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Facebook   Add to Reddit   Add to Technorati   Add to Twitter  
What's this?

© The Rockefeller University Press, 0021-9525/1998//901 $5.00
The Journal of Cell Biology, Volume 143, Number 4, , 1998 901-910

Regular Articles

In Vivo Function of Hsp90 Is Dependent on ATP Binding and ATP Hydrolysis



Wolfgang M.J. Obermann*, Holger Sondermann*, Alicia A. Russo{ddagger}, Nikola P. Pavletich{ddagger}, and F. Ulrich Hartl*

* Department of Cellular Biochemistry, Max-Planck-Institut für Biochemie, D-82152 Martinsried, Germany; and {ddagger} Cellular Biochemistry and Biophysics Program and Howard Hughes Medical Institute, Memorial Sloan-Kettering Cancer Center, New York, New York 10021

Heat shock protein 90 (Hsp90), an abundant molecular chaperone in the eukaryotic cytosol, is involved in the folding of a set of cell regulatory proteins and in the re-folding of stress-denatured polypeptides. The basic mechanism of action of Hsp90 is not yet understood. In particular, it has been debated whether Hsp90 function is ATP dependent. A recent crystal structure of the NH2-terminal domain of yeast Hsp90 established the presence of a conserved nucleotide binding site that is identical with the binding site of geldanamycin, a specific inhibitor of Hsp90. The functional significance of nucleotide binding by Hsp90 has remained unclear. Here we present evidence for a slow but clearly detectable ATPase activity in purified Hsp90. Based on a new crystal structure of the NH2-terminal domain of human Hsp90 with bound ADP-Mg and on the structural homology of this domain with the ATPase domain of Escherichia coli DNA gyrase, the residues of Hsp90 critical in ATP binding (D93) and ATP hydrolysis (E47) were identified. The corresponding mutations were made in the yeast Hsp90 homologue, Hsp82, and tested for their ability to functionally replace wild-type Hsp82. Our results show that both ATP binding and hydrolysis are required for Hsp82 function in vivo. The mutant Hsp90 proteins tested are defective in the binding and ATP hydrolysis–dependent cycling of the co-chaperone p23, which is thought to regulate the binding and release of substrate polypeptide from Hsp90. Remarkably, the complete Hsp90 protein is required for ATPase activity and for the interaction with p23, suggesting an intricate allosteric communication between the domains of the Hsp90 dimer. Our results establish Hsp90 as an ATP-dependent chaperone.

Key Words: heat shock protein 90 • molecular chaperone • p23 • nucleotide binding • geldanamycin

Abbreviations used in this paper: 3-AT, 3-amino-1,2,4-triazole; 5-FOA, 5-fluoroorotic acid; GA, geldanamycin; Hsp, heat shock protein; NTA, nitrilo-triacetic-acid; SD, synthetic dropout medium; TPR, tetratricopeptide repeat.


Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Facebook Facebook   Add to Reddit Reddit   Add to Technorati Technorati   Add to Twitter Twitter    What's this?


This article has been cited by other articles:



  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents