Intracellular trafficking of heat shock factor 2.
HSF2 is an enigmatic member of the heat shock factor family, identified in the homeotherm classes of birds and mammals. We report the characterization of HSF2 from an evolutionary ancient vertebrate, the fish rainbow trout (rtHSF2). rtHSF2 appears closely related to its mammalian counterparts at structural and functional levels. The conservation of the distinctive features of HSF2 from fish to human suggests that it should ensure important biological functions, not redundant with those of HSF1. Proteasome inhibition, reported as a potent stimulator of HSF2, leads to the stabilization and to a striking nuclear trafficking of rtHSF2-GFP fusion protein. Upon treatment with the proteasome inhibitor MG132, rtHSF2-GFP accumulates into PML nuclear bodies (NBs) independently of its sumoylation and, if expressed at moderate level, moves to nucleoli. The translocation of rtHSF2-GFP from NBs to nucleoli is greatly favored by overexpression of the heat shock protein Hsp70. The mammalian counterpart mouse HSF2 (mHSF2) also exhibited changes in intracellular distribution upon MG132 treatment. mHSF2 partitioned between a juxtanuclear area that we characterized as an aggresome and the nucleoli. These relocalizations are likely to reflect common structural changes of mouse and trout HSF2 upon activation.
Le Goff
Pascale
P
UMR CNRS 6026 Information et Programmation Cellulaire, Université de Rennes1, 35042 Rennes Cedex, France. pascale.le-goff@univ-rennes1.fr
Le Dréan
Yves
Y
Le Péron
Christine
C
Le Jossic-Corcos
Catherine
C
Ainouche
Abdelkadder
A
Michel
Denis
D
D021581:Active Transport, Cell Nucleus / Q000502:physiology; D000818:Animals; D016466:CHO Cells; D019556:COS Cells; D002466:Cell Nucleolus / Q000235:genetics / Q000378:metabolism; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism*; D017124:Conserved Sequence; D006224:Cricetinae; D003546:Cysteine Endopeptidases / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019143:Evolution, Molecular; D029941:Fish Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D049452:Green Fluorescent Proteins; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D008164:Luminescent Proteins; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000037:antagonists & inhibitors / Q000378:metabolism; D017686:Oncorhynchus mykiss / Q000378:metabolism*; D010802:Phylogeny; D046988:Proteasome Endopeptidase Complex; D021381:Protein Transport / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D025842:SUMO-1 Protein / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*
D004791:Enzyme Inhibitors; D029941:Fish Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D008164:Luminescent Proteins; D009097:Multienzyme Complexes; D011993:Recombinant Fusion Proteins; D025842:SUMO-1 Protein; D014157:Transcription Factors; C070389:HSF2 protein, human; D049452:Green Fluorescent Proteins; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex