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Purification of Hsp104, a Protein Disaggregase
07:17

Purification of Hsp104, a Protein Disaggregase

Published on: September 30, 2011

Hsp104 binds to yeast Sup35 prion fiber but needs other factor(s) to sever it

Yuji Inoue1, Hideki Taguchi, Aiko Kishimoto

  • 1Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatuta, Yokohama 226-8503, Japan.

The Journal of Biological Chemistry
|September 28, 2004
PubMed

Insights

Heat shock protein 104 (Hsp104) interacts with yeast prion fibers. Hsp104 alone does not sever fibers; cytosolic factors are required for Hsp104-mediated fragmentation, suggesting distinct prion fiber conformations.

Area of Science:

  • Protein biochemistry
  • Molecular biology
  • Yeast genetics

Background:

  • Yeast prions, such as those formed by Sup35NM, are self-propagating protein aggregates.
  • Hsp104 is a key chaperone involved in prion propagation and remodeling in yeast.
  • Previous studies suggested Hsp104 alone can sever prion fibers.

Purpose of the Study:

  • To investigate the interaction of Hsp104 with yeast prion fibers.
  • To determine the conditions required for Hsp104-mediated prion fiber fragmentation.
  • To explore the heterogeneity of yeast prion fibers.

Main Methods:

  • Fluorescent labeling of Hsp104 to visualize its interaction with Sup35NM fibers.
  • Monitoring fiber formation kinetics in the presence of Hsp104.
  • Assessing fiber fragmentation using bead-tethered assays with Hsp104, yeast cell lysate, and Hsp104-deficient lysate.

Main Results:

  • Hsp104 uniformly decorated preformed Sup35NM fibers, with varying fluorescence density suggesting fiber subspecies.
  • Hsp104 delayed the de novo formation of Sup35NM fibers.
  • Hsp104 alone did not fragment fibers; ATP-dependent fragmentation required additional factors present in yeast cytosol.

Conclusions:

  • Yeast prion fibers exhibit heterogeneity in their structure.
  • Hsp104 requires co-factors from the yeast cytosol for prion fiber severing activity.
  • Discrepancies with prior reports may arise from differences in prion fiber conformational states used in experiments.

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