Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
42
pubmed:dateCreated
2002-10-15
pubmed:abstractText
Many features of the chaperone action of clusterin are similar to those of the intracellular small heat shock proteins (sHSPs) that, like clusterin, exist in solution as heterogeneous aggregates. Increased temperature induces dissociation of some sHSP aggregates and an enhanced chaperone action, suggesting that a dissociated form is the active chaperone species. We recently reported that clusterin aggregates dissociate at mildly acidic pH. To further explore the similarities between clusterin and the sHSPs, we tested the effects of temperature and pH on the structure of clusterin and its chaperone action. Our results demonstrate that increased temperature does not induce dissociation of clusterin aggregates, or other major structural changes, and has little effect on its chaperone action. However, we show that the chaperone action of clusterin is enhanced at mildly acidic pH. Clusterin is the first chaperone shown to be activated by reduced pH. This unique mode of activation appears to result from an increase in regions of solvent-exposed hydrophobicity, which is independent of any major changes in secondary or tertiary structure. We propose a model in which low pH-induced dissociation of clusterin aggregates increases the abundance of the heterodimeric chaperone-active species, which has greater hydrophobicity exposed to solution.
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
18
pubmed:volume
277
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
39532-40
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:12176985-Anilino Naphthalenesulfonates, pubmed-meshheading:12176985-Animals, pubmed-meshheading:12176985-Cattle, pubmed-meshheading:12176985-Circular Dichroism, pubmed-meshheading:12176985-Clusterin, pubmed-meshheading:12176985-Dimerization, pubmed-meshheading:12176985-Dose-Response Relationship, Drug, pubmed-meshheading:12176985-Enzyme-Linked Immunosorbent Assay, pubmed-meshheading:12176985-Fluorescent Dyes, pubmed-meshheading:12176985-Glycoproteins, pubmed-meshheading:12176985-Humans, pubmed-meshheading:12176985-Hydrogen-Ion Concentration, pubmed-meshheading:12176985-Lens, Crystalline, pubmed-meshheading:12176985-Molecular Chaperones, pubmed-meshheading:12176985-Protein Binding, pubmed-meshheading:12176985-Protein Structure, Secondary, pubmed-meshheading:12176985-Protein Structure, Tertiary, pubmed-meshheading:12176985-Spectrophotometry, pubmed-meshheading:12176985-Temperature, pubmed-meshheading:12176985-Time Factors
pubmed:year
2002
pubmed:articleTitle
Mildly acidic pH activates the extracellular molecular chaperone clusterin.
pubmed:affiliation
Department of Biological Sciences, University of Wollongong, Northfields Ave., Wollongong, New South Wales 2522, Australia.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't