Linked Life Data

17142456

Source:http://linkedlifedata.com/resource/pubmed/id/17142456

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2007-1-29
pubmed:abstractText
The yeast prion [PSI+] is a self-propagating amyloidogenic isoform of the translation termination factor Sup35. Overproduction of the chaperone protein Hsp104 results in loss of [PSI+]. Here we demonstrate that this effect is decreased by deletion of either the gene coding for one of the major yeast ubiquitin-conjugating enzymes, Ubc4, or the gene coding for the ubiquitin-recycling enzyme, Ubp6. The effect of ubc4Delta on [PSI+] loss was increased by depletion of the Hsp70 chaperone Ssb but was not influenced by depletion of Ubp6. This indicates that Ubc4 affects [PSI+] loss via a pathway that is the same as the one affected by Ubp6 but not by Ssb. In the presence of Rnq1 protein, ubc4Delta also facilitates spontaneous de novo formation of [PSI+]. This stimulation is independent of [PIN+], the prion isoform of Rnq1. Numerous attempts failed to detect ubiquitinated Sup35 in the yeast extracts. While ubc4Delta and other alterations of ubiquitin system used in this work cause slight induction of some Hsps, these changes are insufficient to explain their effect on [PSI+]. However, ubc4Delta increases the proportion of the Hsp70 chaperone Ssa bound to Sup35, suggesting that misfolded Sup35 is either more abundant or more accessible to the chaperones in the absence of Ubc4. The proportion of [PSI+] cells containing large aggregated Sup35 structures is also increased by ubc4Delta. We propose that UPS alterations induce an adaptive response, resulting in accumulation of the large "aggresome"-like aggregates that promote de novo prion generation and prion recovery from the chaperone treatment.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
2
pubmed:volume
282
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3004-13
pubmed:dateRevised
2007-12-3
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Effects of ubiquitin system alterations on the formation and loss of a yeast prion.
pubmed:affiliation
School of Biology and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332-0230, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural