Heat shock protein 27 interacts with vimentin and prevents insolubilization of vimentin subunits induced by cadmium.
Vimentin is an intermediate filament that regulates cell attachment and subcellular organization. In this study, vimentin filaments were morphologically altered, and its soluble subunits were rapidly reduced via cadmium chloride treatment. Cadmium chloride stimulated three major mitogen-activated protein kinases (MAPKs): extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38, and led apoptotic pathway via caspase-9 and caspase-3 activations. In order to determine whether MAPKs were involved in this cadmium-induced soluble vimentin disappearance, we applied MAPK-specific inhibitors (PD98059, SP600125, SB203580). These inhibitors did not abolish the cadmium-induced soluble vimentin disappearance. Caspase and proteosome degradation pathway were also not involved in soluble vimentin disappearance. When we observed vimentin levels in soluble and insoluble fractions, soluble vimentin subunits shifted to an insoluble fraction. As we discovered that heat-shock protein 27 (HSP27) was colocalized and physically associated with vimentin in unstressed cells, the roles of HSP27 with regard to vimentin were assessed. HSP27-overexpressing cells prevented morphological alterations of the vimentin filaments, as well as reductions of soluble vimentin, in the cadmium-treated cells. Moreover, HSP27 antisense oligonucleotide augmented these cadmium-induced changes in vimentin. These findings indicate that HSP27 prevents disruption of the vimentin intermediate filament networks and soluble vimentin disappearance, by virtue of its physical interaction with vimentin in cadmium-treated SK-N-SH cells.
Lee
Jae Seon
JS
ILCHUN Molecular Medicine Institute MRC, Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul 110-799, Korea.
Zhang
Mei Hua
MH
Yun
Eun Kyung
EK
Geum
Dongho
D
Kim
Kyungjin
K
Kim
Tae Hyung
TH
Lim
Yun Sook
YS
Seo
Jeong Sun
JS
D002104:Cadmium / Q000494:pharmacology*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002460:Cell Line; D006360:Heat-Shock Proteins / Q000378:metabolism*; D006801:Humans; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D012995:Solubility / Q000187:drug effects; D014746:Vimentin / Q000737:chemistry* / Q000378:metabolism*
D006360:Heat-Shock Proteins; D021122:Protein Subunits; D014746:Vimentin; D002104:Cadmium; D020928:Mitogen-Activated Protein Kinases; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases