Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2-3
pubmed:dateCreated
2002-3-20
pubmed:abstractText
Clusterin is an extracellular mammalian chaperone protein which inhibits stress-induced precipitation of many different proteins. The conformational state(s) of proteins that interact with clusterin and the stage(s) along the folding and off-folding (precipitation-bound) pathways where this interaction occurs were previously unknown. We investigated this by examining the interactions of clusterin with different structural forms of alpha-lactalbumin, gamma-crystallin and lysozyme. When assessed by ELISA and native gel electrophoresis, clusterin did not bind to various stable, intermediately folded states of alpha-lactalbumin nor to the native form of this protein, but did bind to and inhibit the slow precipitation of reduced alpha-lactalbumin. Reduction-induced changes in the conformation of alpha-lactalbumin, in the absence and presence of clusterin, were monitored by real-time (1)H NMR spectroscopy. In the absence of clusterin, an intermediately folded form of alpha-lactalbumin, with some secondary structure but lacking tertiary structure, aggregated and precipitated. In the presence of clusterin, this form of alpha-lactalbumin was stabilised in a non-aggregated state, possibly via transient interactions with clusterin prior to complexation. Additional experiments demonstrated that clusterin potently inhibited the slow precipitation, but did not inhibit the rapid precipitation, of lysozyme and gamma-crystallin induced by different stresses. These results suggest that clusterin interacts with and stabilises slowly aggregating proteins but is unable to stabilise rapidly aggregating proteins. Collectively, our results suggest that during its chaperone action, clusterin preferentially recognises partly folded protein intermediates that are slowly aggregating whilst venturing along their irreversible off-folding pathway towards a precipitated protein.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0014-5793
pubmed:author
pubmed:issnType
Print
pubmed:day
27
pubmed:volume
513
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
259-66
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Clusterin is an extracellular chaperone that specifically interacts with slowly aggregating proteins on their off-folding pathway.
pubmed:affiliation
Department of Chemistry, University of Wollongong, Northfields Avenue, 2522, Wollongong, NSW, Australia.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't