Chaperones caught partying with prions

Interactions between Endogenous Prions, Chaperones and Poly-glutamine Proteins in the Yeast Model

Prokaryotic chaperones support yeast prions and thermotolerance and define disaggregation machinery interactions.

Saccharomyces cerevisiae Hsp104 and Escherichia coli ClpB are Hsp100 family AAA+ chaperones that provide stress tolerance by cooperating with Hsp70 and Hsp40 to solubilize aggregated protein. Hsp104 also remodels amyloid in vitro and promotes propagation of amyloid prions in yeast, but ClpB does neither, leading to a view that Hsp104 evolved these activities. Although biochemical analyses ident...

Constant Partying: Growing and Handling Trees with Constant Fits

This vignette describes infrastructure for regression and classification trees with simple constant fits in each of the terminal nodes. Thus, all observations that are predicted to be in the same terminal node also receive the same prediction, e.g., a mean for numeric responses or proportions for categorical responses. This class of trees is very common and includes all traditional tree variant...

Prions.

The discovery of infectious proteins, denoted prions, was unexpected. After much debate over the chemical basis of heredity, resolution of this issue began with the discovery that DNA, not protein, from pneumococcus was capable of genetically transforming bacteria (Avery et al. 1944). Four decades later, the discovery that a protein could mimic viral and bacterial pathogens with respect to the ...

Prions.

Infectious proteins (prions) are usually self-templating filamentous protein polymers (amyloids). Yeast prions are genes composed of protein and, like the multiple alleles of DNA-based genes, can have an array of "variants," each a distinct self-propagating amyloid conformation. Like the lethal mammalian prions and amyloid diseases, yeast prions may be lethal, or only mildly detrimental, and sh...