Multiple Domains of the Co-chaperone Hop Are Important for Hsp70 Binding

Carrigan, Patricia E.; Nelson, Gregory M.; Roberts, Patricia J.; Stoffer, Jha'Nae; Riggs, Daniel L.; Smith, David F.

doi:10.1074/jbc.m314130200

Cited by 73 publications

(110 citation statements)

References 40 publications

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“…Hop is a 60-kDa homodimer that links Hsp70 and Hsp90, central components of the regulation of CFTR trafficking, and it Co-IP's with CFTR (3). In addition, Hop is involved in cell-cycle regulation and steroid receptor maturation (24,34,35), and it is homologous to the CHIP complex, of importance to CFTR degradation (36). Hop has a conserved cysteine (C403) (23,24) located in an S-nitrosylation motif believed to be relevant to S-nitrosylation (26).…”

Section: Discussionmentioning

confidence: 99%

Hsp 70/Hsp 90 organizing protein as a nitrosylation target in cystic fibrosis therapy

Marozkina¹,

Yemen²,

Borowitz³

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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The endogenous signaling molecule S-nitrosoglutathione (GSNO) and other S-nitrosylating agents can cause full maturation of the abnormal gene product ΔF508 cystic fibrosis (CF) transmembrane conductance regulator (CFTR). However, the molecular mechanism of action is not known. Here we show that Hsp70/Hsp90 organizing protein (Hop) is a critical target of GSNO, and its S-nitrosylation results in ΔF508 CFTR maturation and cell surface expression. S-nitrosylation by GSNO inhibited the association of Hop with CFTR in the endoplasmic reticulum. This effect was necessary and sufficient to mediate GSNO-induced cell-surface expression of ΔF508 CFTR. Hop knockdown using siRNA recapitulated the effect of GSNO on ΔF508 CFTR maturation and expression. Moreover, GSNO acted additively with decreased temperature, which promoted mutant CFTR maturation through a Hop-independent mechanism. We conclude that GSNO corrects ΔF508 CFTR trafficking by inhibiting Hop expression, and that combination therapiesusing differing mechanisms of action-may have additive benefits in treating CF.cystic fibrosis transmembrane conductance regulator | S-nitrosoglutathione corrector | treatment

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Section: Discussionmentioning

confidence: 99%

Hsp 70/Hsp 90 organizing protein as a nitrosylation target in cystic fibrosis therapy

Marozkina¹,

Yemen²,

Borowitz³

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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“…An intriguing parallel may exist with the complex of Hip-hsp70-Hop. Like hsp90, hsp70 has an EEVD sequence at its C terminus which appears to be part of the Hop-binding domain near the C terminus of hsp70 (5,43). However, while the cochaperone Hip binds hsp70 through its TPR domain, it binds to a site, yet to be identified, in the N-terminal ATPase domain of hsp70 (10,34).…”

Section: Discussionmentioning

confidence: 99%

GCUNC-45 Is a Novel Regulator for the Progesterone Receptor/hsp90 Chaperoning Pathway

Chadli

Graham

Abel

et al. 2006

Molecular and Cellular Biology

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The hsp90 chaperoning pathway is a multiprotein system that is required for the production or activation of many cell regulatory proteins, including the progesterone receptor (PR). We report here the identity of GCUNC-45 as a novel modulator of PR chaperoning by hsp90. GCUNC-45, previously implicated in the activities of myosins, can interact in vivo and in vitro with both PR-A and PR-B and with hsp90. Overexpression and knockdown experiments show GCUNC-45 to be a positive factor in promoting PR function in the cell. GCUNC-45 binds to the ATP-binding domain of hsp90 to prevent the activation of its ATPase activity by the cochaperone Aha1. This effect limits PR chaperoning by hsp90, but this can be reversed by FKBP52, a cochaperone that is thought to act later in the pathway. These findings reveal a new cochaperone binding site near the N terminus of hsp90, add insight on the role of FKBP52, and identify GCUNC-45 as a novel regulator of the PR signaling pathway.The activities of the progesterone receptor (PR) are intimately linked to its associations with other proteins that are essential for normal progesterone action. Unliganded PR is associated with a multifunctional complex of proteins which includes the heat shock proteins hsp70 and hsp90 plus several cochaperone proteins. This heterocomplex is responsible for correct assembly and folding of the PR as well as preventing its degradation (36). Recent studies indicate additional roles for molecular chaperones in receptor trafficking and in the maintenance of receptor function in the nucleus (11,12). Hormone binding promotes conformational changes in the PR and its release from the chaperone complex. The resulting PR dimer is then able to associate with specific coactivators and general transcription factors as well as progestin response elements in the promoters of target genes (13,19,27,44,50).Cell-free systems using the purified proteins have been of crucial importance in dissecting the ordered pathway that leads to the hormone-responsive state of the receptor (36,39,52). This hsp90-dependent chaperoning pathway is initiated by hsp40 and hsp70 binding to PR, followed by the binding of Hop-hsp90 to hsp70 (16). This intermediate complex is then modified by loss of hsp70 and Hop and recruitment of p23, resulting in a receptor able to bind hormone. In the cell, this last step also incorporates the cochaperone FKBP51, FKBP52, or Cyp40, but this step has eluded dissection in vitro.Although the overall mechanism might be as described above, details and dynamics of this process are still unclear. Furthermore, several additional proteins have been discovered recently that interact with hsp90 or hsp70, such as Chip, Bag1, TPR2, and Aha1 (23,31,36,39,52). These are all likely to have important roles in some aspect of hsp70/hsp90 chaperoning to provide a more intricate and versatile process than that described in the current model. There are also a number of proteins that interact with the PR as transcriptional coregulators or to relate PR functions with other cell signa...

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“…Briefly, a series of Hop deletion mutants (glutathione S-transferase (GST)-TPR1, residues 1-104; GST-N (1-224), residues 1-224; GST-C (225-543), residues 225-543; GST-TPR2A, residues 225-359; GST-TPR2B, residues 360 -461; GST-DP2, residues 462-543) were prepared by PCR using the expression plasmid pGEX4T2-Hop wild type (WT; which encodes wild type rat Hop) as the template. Hop point mutants were generated as previously described (29). The single point mutations in the each domain were generated as follows: TPR1, Y27A and K73E; TPR2A, K301E and R305E; TPR2B, K429E and R433E.…”

Section: Methodsmentioning

confidence: 99%

“…1B. Hop contains three separate TPR domains, TPR1, TPR2A, and TPR2B, and two regions that contain aspartic acid-proline (DP) residue repeats; DP1 after TPR1 and DP2 after TPR2B (28,29). The TPR1 domain of Hop co-crystallizes with a heptapeptide containing terminal EEVD residues in Hsp70, and the TPR2A domain of Hop co-crystallizes with a pentapeptide containing the terminal MEEVD residues of Hsp90 (9).…”

Section: Interaction Between Hop and The Members Of The S100 Proteinmentioning

confidence: 99%

“…Crystallographic studies (9) have shown that EEVD interacts with basic amino acids (called calboxylate clamp) in Hop TPR binding pockets, and point mutations altering these calboxylate clamp residues to acidic amino acids can disrupt Hsp binding (29). To further explore the interaction between Hop and S100 proteins, we performed GST pulldown assays using Hop mutants of the calboxylate clamp residue in each TPR domain.…”

Section: Point Mutations Of the Hsp Binding Site Within Hop Had Littlmentioning

confidence: 99%

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Interactions of S100A2 and S100A6 with the Tetratricopeptide Repeat Proteins, Hsp90/Hsp70-organizing Protein and Kinesin Light Chain

Shimamoto

Takata

Tokuda

et al. 2008

Journal of Biological Chemistry

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S100A2 and S100A6 interact with several target proteins in a Ca 2؉-regulated manner. However, the exact intracellular roles of the S100 proteins are unclear. In this study we identified Hsp70/ Hsp90-organizing protein (Hop) and kinesin light chain (KLC) as novel targets of S100A2 and S100A6. Hop directly associates with Hsp70 and Hsp90 through the tetratricopeptide (TPR) domains and regulates Hop-Hsp70 and Hop-Hsp90 complex formation. We have found that S100A2 and S100A6 bind to the TPR domain of Hop, resulting in inhibition of the Hop-Hsp70 and Hop-Hsp90 interactions in vitro. Although endogenous Hsp70 and Hsp90 interact with Hop in resting Cos-7 cells, but not with S100A6, stimulation of these cells with ionomycin caused a Hop-S100A6 interaction, resulting in the dissociation of Hsp70 and Hsp90 from Hop. Similarly, glutathione S-transferase pulldown and co-immunoprecipitation experiments revealed that S100A6 binds to the TPR domain of KLC, resulting in inhibition of the KLC-c-Jun N-terminal kinase (JNK)-interacting protein 1 (JIP-1) interaction in vitro. The transiently expressed JIP-1 interacts with KLC in resting Cos-7 cells but not with S100A6. Stimulation of these cells with ionomycin also caused a KLC-S100A6 interaction, resulting in dissociation of JIP-1 from KLC. These results strongly suggest that the S100 proteins modulate Hsp70-Hop-Hsp90 multichaperone complex formation and KLC-cargo interaction via Ca 2؉ -dependent S100 protein-TPR protein complex formation in vivo as well as in vitro. Moreover, we have shown that S100A2 and S100A6 interact with another TPR protein Tom70 and regulate the Tom70-ligand interaction in vitro. Thus, our findings suggest a new intracellular Ca 2؉

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Multiple Domains of the Co-chaperone Hop Are Important for Hsp70 Binding

Cited by 73 publications

References 40 publications

Hsp 70/Hsp 90 organizing protein as a nitrosylation target in cystic fibrosis therapy

Hsp 70/Hsp 90 organizing protein as a nitrosylation target in cystic fibrosis therapy

GCUNC-45 Is a Novel Regulator for the Progesterone Receptor/hsp90 Chaperoning Pathway

Interactions of S100A2 and S100A6 with the Tetratricopeptide Repeat Proteins, Hsp90/Hsp70-organizing Protein and Kinesin Light Chain

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