Related Experiment Video

Updated: Jul 19, 2026

Purification of Hsp104, a Protein Disaggregase
07:17

Purification of Hsp104, a Protein Disaggregase

Published on: September 30, 2011

Hsp104 catalyzes formation and elimination of self-replicating Sup35 prion conformers

James Shorter1, Susan Lindquist

  • 1Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, MA 02142, USA.

Science (New York, N.Y.)
|May 25, 2004
PubMed

Insights

The protein Hsp104 regulates yeast prion [PSI+] inheritance by promoting Sup35 amyloid formation at low concentrations and disassembling fibers at high concentrations, explaining inheritance patterns.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Yeast Genetics

Background:

  • The protein-remodeling factor Hsp104 is crucial for the inheritance of the yeast prion [PSI+].
  • The prion [PSI+] is formed by self-perpetuating amyloid conformers of the translation termination factor Sup35.
  • Both excess and insufficient levels of Hsp104 lead to the elimination of [PSI+].

Purpose of the Study:

  • To investigate the dual role of Hsp104 in yeast prion [PSI+] inheritance.
  • To elucidate the mechanisms by which Hsp104 concentration affects Sup35 fibrillization and prion propagation.
  • To explain the observed inheritance patterns of [PSI+] based on Hsp104 activity.

Main Methods:

  • In vitro studies using purified Hsp104 and Sup35.
  • Analysis of Hsp104-catalyzed formation of Sup35 oligomeric intermediates.
  • Investigation of Hsp104's effect on de novo Sup35 fibrillization.
  • Assessment of Hsp104's disassembly of mature Sup35 fibers.

Main Results:

  • At low concentrations, Hsp104 catalyzed amyloidogenic oligomer formation, essential for Sup35 fibril nucleation.
  • Higher Hsp104 concentrations inhibited amyloid oligomerization and fibrillization.
  • Hsp104 disassembled mature fibers, initially exposing surfaces for replication, but ultimately leading to prion extermination.
  • Distinct reaction mechanisms underlie Hsp104's concentration-dependent activities.

Conclusions:

  • Hsp104's concentration-dependent activities explain the complex inheritance patterns of the yeast prion [PSI+].
  • The dual role of Hsp104 in promoting and inhibiting amyloid formation is key to prion stability.
  • Understanding Hsp104's mechanism provides insights into protein-only inheritance and conformational templating.

More Related Videos

Isolating Potentiated Hsp104 Variants Using Yeast Proteinopathy Models08:44

Isolating Potentiated Hsp104 Variants Using Yeast Proteinopathy Models

Published on: November 11, 2014

Defining Hsp33's Redox-regulated Chaperone Activity and Mapping Conformational Changes on Hsp33 Using Hydrogen-deuterium Exchange Mass Spectrometry10:24

Defining Hsp33's Redox-regulated Chaperone Activity and Mapping Conformational Changes on Hsp33 Using Hydrogen-deuterium Exchange Mass Spectrometry

Published on: June 7, 2018

Related Concept Videos

DNA Helicases00:55

DNA Helicases

DNA unwinding helicase enzymes are a type of motor protein. Motor proteins can translocate along filaments or polymers using energy generated from ATP hydrolysis. Helicases are involved in all the important cellular processes where DNA unwinding is required, such as DNA replication, repair, recombination, and transcription. They are present in all living organisms, but vary in their structure, function, and mechanism of action. For example, in prokaryotes, DnaB helicase binds and translocates...
DNA Topoisomerases02:02

DNA Topoisomerases

Topoisomerases are enzymes that relax overwound DNA molecules during various cell processes, including DNA replication and transcription. These enzymes regulate positive and negative DNA supercoiling without changing the nucleotide sequence. DNA overwinding in a clockwise direction results in positively supercoiled DNA, whereas underwinding in a counterclockwise direction produces negatively supercoiled DNA.
Types and Mechanism of action
Topoisomerases are divided into two main types.  Type I...
Homologous Recombination02:31

Homologous Recombination

The basic reaction of homologous recombination (HR) involves two chromatids that contain DNA sequences sharing a significant stretch of identity. One of these sequences uses a strand from another as a template to synthesize DNA in an enzyme-catalyzed reaction. The final product is a novel amalgamation of the two substrates. To ensure an accurate recombination of sequences, HR is restricted to the S and G2 phases of the cell cycle. At these stages, the DNA has been replicated already and the...
Restarting Stalled Replication Forks02:37

Restarting Stalled Replication Forks

DNA replication is initiated at sites containing predefined DNA sequences known as origins of replication. DNA is unwound at these sites by the minichromosome maintenance (MCM) helicase and other factors such as Cdc45 and the associated GINS complex.The unwound single strands are protected by replication protein A (RPA) until DNA polymerase starts synthesizing DNA at the 5’ end of the strand in the same direction as the replication fork. To prevent the replication fork from falling apart, a...
Gene Conversion02:08

Gene Conversion

Other than maintaining genome stability via DNA repair, homologous recombination plays an important role in diversifying the genome. In fact, the recombination of sequences forms the molecular basis of genomic evolution. Random and non-random permutations of genomic sequences create a library of new amalgamated sequences. These newly formed genomes can determine the fitness and survival of cells. In bacteria, homologous and non-homologous types of recombination lead to the evolution of new...
Conservative Site-specific Recombination and Phase Variation02:53

Conservative Site-specific Recombination and Phase Variation

Because the DNA segments are cut and reorganized in a direction-specific manner, site-specific recombination has emerged as an efficient genetic engineering technique. Flippase and Cyclization recombinases or Flp and Cre, respectively, are two members of the tyrosine recombinase family derived from bacteriophages, that are used to mediate site-specific DNA insertions, deletions, and targeted expression of proteins in mammalian cell lines.
The recognition sites for Cre recombinase called LoxP...