Linked Life Data

12621024

Source:http://linkedlifedata.com/resource/pubmed/id/12621024

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
19
pubmed:dateCreated
2003-5-5
pubmed:abstractText
Heat shock factor 1 (HSF1) regulates the rapid and transient expression of heat shock genes in response to stress. The transcriptional activity of HSF1 is tightly controlled, and under physiological growth conditions, the HSF1 monomer is in a heterocomplex with the molecular chaperone HSP90. Through unknown mechanisms, transcriptionally repressed HSF1.HSP90 heterocomplexes dissociate following stress, which triggers HSF1 activation and heat shock gene transcription. Using a yeast two-hybrid screening system, we have identified Ral-binding protein 1 (RalBP1) as an additional HSF1-interacting protein. We show that RalBP1 and HSF1 interact in vivo, and transient cotransfection of HSF1 and RalBP1 into hsf1(-/-) mouse embryo fibroblasts represses HSP70 expression. Furthermore, transient cotransfection of HSF1 and the constitutively active form of RalA (RalA23V), an upstream activator of the RalBP1 signaling pathway, increases the heat-inducible expression of HSP70, whereas the dominant negative form (RalA28N) suppresses HSP70 expression. We further find that alpha-tubulin and HSP90 are also present in the RalBP1.HSF1 heterocomplexes in unstressed cells. Upon heat shock, the Ral signaling pathway is activated, and the resulting RalGTP binds RalBP1. Concurrently, HSF1 is activated, leaves the RalBP1 x HSF1 x HSP90 x alpha-tubulin heterocomplexes, and translocates into the nucleus, where it then activates transcription. In conclusion, these observations reveal that the RalGTP signal transduction pathway is critical for activation of the stress-responsive HSF1 and perhaps HSP90 molecular chaperone system.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
9
pubmed:volume
278
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
17299-306
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
HSF-1 interacts with Ral-binding protein 1 in a stress-responsive, multiprotein complex with HSP90 in vivo.
pubmed:affiliation
Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, Georgia 30912, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.