title: The small heat shock protein, HSP30, is associated with aggresome-like inclusion bodies in proteasomal inhibitor-, arsenite-, and cadmium-treated Xenopus kidney cells.
abstract: In the present study, treatment of Xenopus laevis A6 kidney epithelial cells with the proteasomal inhibitor, MG132, or the environmental toxicants, sodium arsenite or cadmium chloride, induced the accumulation of the small heat shock protein, HSP30, in total and in both soluble and insoluble protein fractions. Immunocytochemical analysis revealed the presence of relatively large HSP30 structures primarily in the perinuclear region of the cytoplasm. All three of the stressors promoted the formation of aggresome-like inclusion bodies as determined by immunocytochemistry and laser scanning confocal microscopy using a ProteoStat aggresome dye and additional aggresomal markers, namely, anti-γ-tubulin and anti-vimentin antibodies. Further analysis revealed that HSP30 co-localized with these aggresome-like inclusion bodies. In most cells, HSP30 was found to envelope or occur within these structures. Finally, we show that treatment of cells with withaferin A, a steroidal lactone with anti-inflammatory, anti-tumor, and proteasomal inhibitor properties, also induced HSP30 accumulation that co-localized with aggresome-like inclusion bodies. It is possible that proteasomal inhibitor or metal/metalloid-induced formation of aggresome-like inclusion bodies may sequester toxic protein aggregates until they can be degraded. While the role of HSP30 in these aggresome-like structures is not known, it is possible that they may be involved in various aspects of aggresome-like inclusion body formation or transport.
authors.affiliation: Department of Biology, University of Waterloo, Waterloo, ON, Canada N2L 3G1.
authors.forename: Saad
authors.initials: S
authors.lastname: Khan
authors.affiliation: Department of Biology, University of Waterloo, Waterloo, ON, Canada N2L 3G1.
authors.forename: Imran
authors.initials: I
authors.lastname: Khamis
authors.affiliation: Department of Biology, University of Waterloo, Waterloo, ON, Canada N2L 3G1. Electronic address: heikkila@uwaterloo.ca.
authors.forename: John J
authors.initials: JJ
authors.lastname: Heikkila
mesh_terms: D000818:Animals; D018053:Arsenites / Q000494:pharmacology*; D002104:Cadmium / Q000494:pharmacology*; D002460:Cell Line; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004847:Epithelial Cells / Q000187:drug effects* / Q000378:metabolism; D050890:HSP30 Heat-Shock Proteins / Q000378:metabolism*; D015151:Immunoblotting; D007150:Immunohistochemistry; D002479:Inclusion Bodies / Q000378:metabolism*; D007668:Kidney / Q000166:cytology; D007976:Leupeptins / Q000494:pharmacology*; D018613:Microscopy, Confocal; D014404:Tubulin / Q000378:metabolism; D014746:Vimentin / Q000378:metabolism; D054358:Withanolides / Q000494:pharmacology; D029867:Xenopus Proteins / Q000378:metabolism*; D014982:Xenopus laevis
chemical_list: D018053:Arsenites; D015853:Cysteine Proteinase Inhibitors; D050890:HSP30 Heat-Shock Proteins; D007976:Leupeptins; D014404:Tubulin; D014746:Vimentin; D054358:Withanolides; D029867:Xenopus Proteins; C494391:hsp30 protein, Xenopus; D002104:Cadmium; C009684:withaferin A; C015001:arsenite; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde
keywords: Amphibian; Frog; Heat shock protein; Immunoblots; Immunocytochemistry; Molecular chaperone; Proteasome; Protein aggregates; Xenopus