|
|
| J. Biol. Chem. Jun (2008); 283(23):15732-9 | |
| Molecular chaperones and the assembly of the prion Ure2p in vitro- | |
| Savistchenko J, Krzewska J, Fay N, Melki R | |
| Laboratoire d'Enzymologie et Biochimie Structurales, CNRS, 91198 Gif-sur-Yvette Cedex, France- | |
| Abstract: The protein Ure2 from Saccharomyces cerevisiae possesses prion properties at the origin of the [URE3] trait- In vivo, a high molecular weight form of inactive Ure2p is associated to [URE3]- The faithful and continued propagation of [URE3]is dependent on the expression levels of molecular chaperones from the Hsp100, -70, and -40 families; however, so far, their role is not fully documented- Here we investigate the effects of molecular chaperones from the Hsp40, Hsp70, Hsp90, and Hsp100 families and the chaperonin CCT-Tric on the assembly of full-length Ure2p- We show that Hsp104p greatly stimulates Ure2p aggregation, whereas Ssa1p, Ydj1p, Sis1p, and Hsp82p inhibit aggregation to different extents- The nature of the high molecular weight Ure2p species that forms in the presence of the different molecular chaperones and their nucleotide dependence is described- We show that Hsp104p favors the aggregation of Ure2p into non-fibrillar high molecular weight particles, whereas Ssa1p, Ydj1p, Sis1p, and Hsp82p sequester Ure2p in spherical oligomers- Using fluorescently labeled full-length Ure2p and Ure2p--94-354- and fluorescence polarization, we show that Ssa1p binding to Ure2p is ATP-dependent, whereas that of Hsp104p is not- We also show that Ssa1p preferentially interacts with the N-terminal domain of Ure2p that is critical for prion propagation, whereas Ydj1p preferentially interacts with the C-terminal domain of the protein, and we discuss the significance of this observation- Finally, the affinities of Ssa1p, Ydj1p, and Hsp104p for Ure2p are determined- Our in vitro observations bring new insight into the mechanism by which molecular chaperones influence the propagation of [URE3]- | |
| [PUBMED: 18400756] |   |
| Copyright © 2009, Tyers Lab, The Samuel Lunenfeld Research Institute, Mount Sinai Hospital, All Rights Reserved. |
| terms and conditions - privacy policy - Osprey Network Visualization System |
| BioGRID: A General Repository for Interaction Datasets. Chris Stark, Bobby-Joe Breitkreutz, Teresa Reguly, Lorrie Boucher, Ashton Breitkreutz, Mike Tyers. Nucleic Acids Res. Jan 1;34:D535-9. |