Heat Shock Protein 90 Recognized as an Iron-Binding Protein Associated with the Plasma Membrane of HeLa Cells

Three 59Fe-labeled nonheme components of the cytosol were identified when rabbit reticuloyctes were incubated with 59Fe-labeled plasma under conditions in which the iron supply was not limiting. Two of these components were identified as ferritin and transferrin. The latter was characterized by gel filtration as having apparent molecular weight higher than transferrin, indicating that the transferrin may be complexed to another moiety. The third component, referred to as iron- binding protein-I (IBP-I), is as yet uncharacterized. When the reticulocytes were incubated with unlabeled plasma after pulse-labeling with 59Fe-labeled plasma, 59Fe radioactivity in these cytosol components decreased; after 15 min of chase, the 59Fe in ferritin, transferrin, and IBP-I fell to 64.6%, 26.5%, and 65.8% of the initial values, respectively. A good correlation existed between the decrease of 59Fe in these three nonheme compartments and the associated increase in 59Fe-heme. The data presented suggest that cytosol ferritin, transferrin, and IBP-I are intermediates in the transport of 59Fe from the plasma membrane to the mitochondria.

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The Inhibition of Heat Shock Protein 90 Facilitates the Degradation of Poly-Alanine Expanded Poly (A) Binding Protein Nuclear 1 via the Carboxyl Terminus of Heat Shock Protein 70-Interacting Protein

PLoS ONE ◽

10.1371/journal.pone.0138936 ◽

2015 ◽

Vol 10 (9) ◽

pp. e0138936 ◽

Cited By ~ 3

Author(s):

Chao Shi ◽

Xuan Huang ◽

Bin Zhang ◽

Dan Zhu ◽

Huqiao Luo ◽

...

Keyword(s):

Heat Shock ◽

Heat Shock Protein ◽

Heat Shock Protein 70 ◽

Binding Protein ◽

Heat Shock Protein 90 ◽

Carboxyl Terminus ◽

Interacting Protein

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Cytosol intermediates in the transport of iron

Blood ◽

10.1182/blood.v55.6.1051.1051 ◽

1980 ◽

Vol 55 (6) ◽

pp. 1051-1055 ◽

Cited By ~ 23

Author(s):

MT Nunez ◽

ES Cole ◽

J Glass

Keyword(s):

Molecular Weight ◽

Plasma Membrane ◽

Binding Protein ◽

Gel Filtration ◽

Apparent Molecular Weight ◽

Iron Binding ◽

The Third ◽

Initial Values ◽

Iron Supply ◽

Iron Binding Protein

Abstract Three 59Fe-labeled nonheme components of the cytosol were identified when rabbit reticuloyctes were incubated with 59Fe-labeled plasma under conditions in which the iron supply was not limiting. Two of these components were identified as ferritin and transferrin. The latter was characterized by gel filtration as having apparent molecular weight higher than transferrin, indicating that the transferrin may be complexed to another moiety. The third component, referred to as iron- binding protein-I (IBP-I), is as yet uncharacterized. When the reticulocytes were incubated with unlabeled plasma after pulse-labeling with 59Fe-labeled plasma, 59Fe radioactivity in these cytosol components decreased; after 15 min of chase, the 59Fe in ferritin, transferrin, and IBP-I fell to 64.6%, 26.5%, and 65.8% of the initial values, respectively. A good correlation existed between the decrease of 59Fe in these three nonheme compartments and the associated increase in 59Fe-heme. The data presented suggest that cytosol ferritin, transferrin, and IBP-I are intermediates in the transport of 59Fe from the plasma membrane to the mitochondria.

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Disruption of Heat Shock Protein 90 (Hsp90)-Protein Kinase Cδ (PKCδ) Interaction by (−)-Maackiain Suppresses Histamine H1 Receptor Gene Transcription in HeLa Cells

Journal of Biological Chemistry ◽

10.1074/jbc.m115.657023 ◽

2015 ◽

Vol 290 (45) ◽

pp. 27393-27402 ◽

Cited By ~ 10

Author(s):

Yuki Nariai ◽

Hiroyuki Mizuguchi ◽

Takeyasu Ogasawara ◽

Hiroaki Nagai ◽

Yohei Sasaki ◽

...

Keyword(s):

Heat Shock ◽

Protein Kinase ◽

Heat Shock Protein ◽

Gene Transcription ◽

Hela Cells ◽

Receptor Gene ◽

Heat Shock Protein 90 ◽

H1 Receptor ◽

Hsp90 Protein ◽

Protein Kinase Cδ

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Heat Shock Protein 90 Modulates Lipid Homeostasis by Regulating the Stability and Function of Sterol Regulatory Element-binding Protein (SREBP) and SREBP Cleavage-activating Protein

Journal of Biological Chemistry ◽

10.1074/jbc.m116.767277 ◽

2016 ◽

Vol 292 (7) ◽

pp. 3016-3028 ◽

Cited By ~ 27

Author(s):

Yen-Chou Kuan ◽

Tsutomu Hashidume ◽

Takahiro Shibata ◽

Koji Uchida ◽

Makoto Shimizu ◽

...

Keyword(s):

Heat Shock ◽

Heat Shock Protein ◽

Binding Protein ◽

Regulatory Element ◽

Heat Shock Protein 90 ◽

Lipid Homeostasis ◽

Element Binding Protein ◽

Sterol Regulatory Element ◽

The Stability ◽

And Function

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Structure-Function Analysis of Squirrel Monkey FK506-Binding Protein 51, a Potent Inhibitor of Glucocorticoid Receptor Activity

Endocrinology ◽

10.1210/en.2005-0027 ◽

2005 ◽

Vol 146 (7) ◽

pp. 3194-3201 ◽

Cited By ~ 43

Author(s):

Wesley B. Denny ◽

Viravan Prapapanich ◽

David F. Smith ◽

Jonathan G. Scammell

Keyword(s):

Heat Shock ◽

Heat Shock Protein ◽

Glucocorticoid Receptor ◽

Squirrel Monkey ◽

Inhibitory Activity ◽

Function Analysis ◽

Binding Protein ◽

Heat Shock Protein 90 ◽

Ppiase Activity ◽

Fk506 Binding Protein

Abstract FK506-binding protein 51 (FKBP51) and FKBP52 are large molecular weight immunophilins that are part of the mature glucocorticoid receptor (GR) heterocomplex. These proteins possess peptidyl-prolyl isomerase (PPIase) and tetratricopeptide repeats (TPR) domains that are important for modulation of GR activity. A naturally occurring animal model of glucocorticoid resistance, the squirrel monkey, results from the relative overexpression of FKBP51 that renders the GR in a low-affinity state. In vitro studies demonstrated that the squirrel monkey form of FKBP51 is greater than 6-fold more potent than human FKBP51 in this respect. The goals of these studies were to determine the roles of the TPR and PPIase domains in the inhibitory activity of squirrel monkey FKBP51 and to gain insight into structural features of squirrel monkey FKBP51 responsible for potent inhibition of dexamethasone-stimulated GR activity. Mutations in the TPR of squirrel monkey FKBP51 that inhibit association with heat shock protein 90 blocked GR inhibitory activity. Mutations that abrogate the PPIase activity of squirrel monkey FKBP51 had no effect on GR inhibitory activity. Chimeras of squirrel monkey and human FKBP51 were tested to identify domains responsible for their different inhibitory potencies. Amino acid differences in domains FK1 and FK2 between squirrel monkey and human FKBP51 contribute equally to the enhanced inhibitory activity of squirrel monkey FKBP51. Furthermore, squirrel monkey FKBP51 in which either FK1 or FK2 was deleted lacked GR inhibitory activity. Thus, the potent inhibitory activity of squirrel monkey FKBP51 involves both FK domains and the heat shock protein 90-binding TPR domain.

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