title: Heat shock-induced interactions among nuclear HSFs detected by fluorescence cross-correlation spectroscopy.
abstract: The cellular response to stress is primarily controlled in cells via transcriptional activation by heat shock factor 1 (HSF1). HSF1 is well-known to form homotrimers for activation upon heat shock and subsequently bind to target DNAs, such as heat-shock elements, by forming stress granules. A previous study demonstrated that nuclear HSF1 and HSF2 molecules in live cells interacted with target DNAs on the stress granules. However, the process underlying the binding interactions of HSF family in cells upon heat shock remains unclear. This study demonstrate for the first time that the interaction kinetics among nuclear HSF1, HSF2, and HSF4 upon heat shock can be detected directly in live cells using dual color fluorescence cross-correlation spectroscopy (FCCS). FCCS analyses indicated that the binding between HSFs was dramatically changed by heat shock. Interestingly, the recovery kinetics of interaction between HSF1 molecules after heat shock could be represented by changes in the relative interaction amplitude and mobility.
authors.affiliation: Asan Institute for Life Sciences, University of Ulsan, College of Medicine, Asan Medical Center, Seoul 138-736, Republic of Korea. Electronic address: changipack@amc.seoul.kr.
authors.forename: Chan-Gi
authors.initials: CG
authors.lastname: Pack
authors.affiliation: Dept. of Pathology, College of Dentistry, Chosun University, Seosuk-dong, Dong-gu, Gwangju 501-759, Republic of Korea.
authors.forename: Sang-Gun
authors.initials: SG
authors.lastname: Ahn
mesh_terms: D002467:Cell Nucleus / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000032:analysis / Q000378:metabolism*; D006367:HeLa Cells; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins / Q000032:analysis / Q000378:metabolism*; D018869:Heat-Shock Response; D006801:Humans; D011485:Protein Binding; D025941:Protein Interaction Mapping; D060066:Protein Interaction Maps; D013050:Spectrometry, Fluorescence; D014157:Transcription Factors / Q000032:analysis / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; C000619706:HSF1 protein, human; C102948:HSF4 protein, human; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins; D014157:Transcription Factors; C070389:HSF2 protein, human
keywords: Binding interaction; Fluorescence cross-correlation spectroscopy (FCCS); Heat shock recovery; Heat shock transcription factors (HSFs)