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Baishen Zhang - One of the best experts on this subject based on the ideXlab platform.

  • USP33 suppresses lung adenocarcinoma lung cell invasion and metastasis by down regulating slit2 robo1 signaling pathway
    Journal of Southern Medical University, 2018
    Co-Authors: Yuhuan Wang, Shuhua Zhang, Baishen Zhang
    Abstract:

    Objective To investigate the role of USP33 as an independent prognostic marker in the regulation of SLIT2/ROBO1 signaling pathway to inhibit lung adenocarcinoma invasion and metastasis. Methods The expression of USP33 in 20 lung adenocarcinoma specimens was detected by qPCR and immunohistochemistry. A549 and SPC-A-1 cells with small interfering RNA (siRNA)-mediated USP33 silencing were examined for changes in invasion and metastasis abilities using scratch assay and Matrigel assay. Western blotting was used to detect the expression of SLIT2 and ROBO1 in the cells after USP33 silencing and the expression of USP33 after interleukin-6 (IL-6) stimulation. Results qPCR and immunohistochemistry showed that USP33 was significantly decreased in lung adenocarcinoma tissues as compared with the adjacent tissues. USP33 silencing in A549 and SPC-A-1 cells significantly promoted the cell migration, invasion and metastasis and obviously down-regulated the expressions of SLIT2 and ROBO1. IL-6 stimulation of the cells obviously enhanced the expression of USP33. Conclusions USP33 silencing can promote the migration, invasion and metastasis of lung adenocarcinoma cells in vitro, and the mechanism may involve IL-6 and SLIT2/ROBO1 signaling pathways.

  • microrna 365 promotes lung carcinogenesis by downregulating the USP33 slit2 robo1 signalling pathway
    Cancer Cell International, 2018
    Co-Authors: Yuhuan Wang, Shuhua Zhang, Hejing Bao, Baishen Zhang
    Abstract:

    Abnormal microRNA expression is closely related to cancer occurrence and development. miR-365a-3p plays an oncogenic role in skin cancer, but its role in lung cancer remains unclear. In this study, we aimed to investigate its role and underlying molecular mechanisms in lung cancer. Western blot and real-time quantitative PCR (qPCR) were used to detect the expression of miR-365a-3p in lung adenocarcinoma and lung cancer cell lines. The effects of miR-365a-3p on lung cancer cell proliferation, migration, and invasion were also explored in vitro. The potential miR-365a-3p that targets USP33 was determined by dual luciferase reporter assay and verified by qPCR and western blot analysis. miR-365a-3p acts as an oncogene by promoting lung carcinogenesis via the downregulation of the miR-365a/USP33/SLIT2/ROBO1 axis based on western blot analysis. Subcutaneous tumourigenesis further demonstrated that miR-365a-3p promotes tumour formation in vivo. miR-365a-3p was upregulated in lung adenocarcinoma and lung cancer cell lines. Overexpression of miR-365a-3p promoted and inhibition of miR-365a-3p suppressed the proliferation, migration, and invasion of lung cancer cells. We identified USP33 as the downstream target of miR-365a-3p and observed a negative correlation between miR-365a-3p and USP33 expression in lung adenocarcinoma patients. The miR-365/USP33/SLIT2/ROBO1 axis, a new mechanism, was reported to inhibit the invasion and metastasis of lung cancer. A nude mouse model of lung cancer further verified these findings. In summary, miR-365a-3p acts as an oncogene by promoting lung carcinogenesis via the downregulation of the USP33/SLIT2/ROBO1 signalling pathway, making the miR-365/USP33/SLIT2/ROBO1 axis a new mechanism of lung cancer promotion and a novel therapeutic target for predicting prognosis and response to gene therapy.

  • MOESM4 of MicroRNA-365 promotes lung carcinogenesis by downregulating the USP33/SLIT2/ROBO1 signalling pathway
    2018
    Co-Authors: Yuhuan Wang, Shuhua Zhang, Hejing Bao, Baishen Zhang
    Abstract:

    Additional file 4: Table S1. PCR sequences of miR-365a-3p and USP33. (a) hsa-miR-365a-3p sequence. (b) USP33 3สน UTR primer sequences

  • MicroRNA-365 promotes lung carcinogenesis by downregulating the USP33/SLIT2/ROBO1 signalling pathway
    'Springer Science and Business Media LLC', 2018
    Co-Authors: Yuhuan Wang, Shuhua Zhang, Hejing Bao, Baishen Zhang
    Abstract:

    Abstract Background Abnormal microRNA expression is closely related to cancer occurrence and development. miR-365a-3p plays an oncogenic role in skin cancer, but its role in lung cancer remains unclear. In this study, we aimed to investigate its role and underlying molecular mechanisms in lung cancer. Methods Western blot and real-time quantitative PCR (qPCR) were used to detect the expression of miR-365a-3p in lung adenocarcinoma and lung cancer cell lines. The effects of miR-365a-3p on lung cancer cell proliferation, migration, and invasion were also explored in vitro. The potential miR-365a-3p that targets USP33 was determined by dual luciferase reporter assay and verified by qPCR and western blot analysis. miR-365a-3p acts as an oncogene by promoting lung carcinogenesis via the downregulation of the miR-365a/USP33/SLIT2/ROBO1 axis based on western blot analysis. Subcutaneous tumourigenesis further demonstrated that miR-365a-3p promotes tumour formation in vivo. Results miR-365a-3p was upregulated in lung adenocarcinoma and lung cancer cell lines. Overexpression of miR-365a-3p promoted and inhibition of miR-365a-3p suppressed the proliferation, migration, and invasion of lung cancer cells. We identified USP33 as the downstream target of miR-365a-3p and observed a negative correlation between miR-365a-3p and USP33 expression in lung adenocarcinoma patients. The miR-365/USP33/SLIT2/ROBO1 axis, a new mechanism, was reported to inhibit the invasion and metastasis of lung cancer. A nude mouse model of lung cancer further verified these findings. Conclusions In summary, miR-365a-3p acts as an oncogene by promoting lung carcinogenesis via the downregulation of the USP33/SLIT2/ROBO1 signalling pathway, making the miR-365/USP33/SLIT2/ROBO1 axis a new mechanism of lung cancer promotion and a novel therapeutic target for predicting prognosis and response to gene therapy

Yuhuan Wang - One of the best experts on this subject based on the ideXlab platform.

  • USP33 suppresses lung adenocarcinoma lung cell invasion and metastasis by down regulating slit2 robo1 signaling pathway
    Journal of Southern Medical University, 2018
    Co-Authors: Yuhuan Wang, Shuhua Zhang, Baishen Zhang
    Abstract:

    Objective To investigate the role of USP33 as an independent prognostic marker in the regulation of SLIT2/ROBO1 signaling pathway to inhibit lung adenocarcinoma invasion and metastasis. Methods The expression of USP33 in 20 lung adenocarcinoma specimens was detected by qPCR and immunohistochemistry. A549 and SPC-A-1 cells with small interfering RNA (siRNA)-mediated USP33 silencing were examined for changes in invasion and metastasis abilities using scratch assay and Matrigel assay. Western blotting was used to detect the expression of SLIT2 and ROBO1 in the cells after USP33 silencing and the expression of USP33 after interleukin-6 (IL-6) stimulation. Results qPCR and immunohistochemistry showed that USP33 was significantly decreased in lung adenocarcinoma tissues as compared with the adjacent tissues. USP33 silencing in A549 and SPC-A-1 cells significantly promoted the cell migration, invasion and metastasis and obviously down-regulated the expressions of SLIT2 and ROBO1. IL-6 stimulation of the cells obviously enhanced the expression of USP33. Conclusions USP33 silencing can promote the migration, invasion and metastasis of lung adenocarcinoma cells in vitro, and the mechanism may involve IL-6 and SLIT2/ROBO1 signaling pathways.

  • microrna 365 promotes lung carcinogenesis by downregulating the USP33 slit2 robo1 signalling pathway
    Cancer Cell International, 2018
    Co-Authors: Yuhuan Wang, Shuhua Zhang, Hejing Bao, Baishen Zhang
    Abstract:

    Abnormal microRNA expression is closely related to cancer occurrence and development. miR-365a-3p plays an oncogenic role in skin cancer, but its role in lung cancer remains unclear. In this study, we aimed to investigate its role and underlying molecular mechanisms in lung cancer. Western blot and real-time quantitative PCR (qPCR) were used to detect the expression of miR-365a-3p in lung adenocarcinoma and lung cancer cell lines. The effects of miR-365a-3p on lung cancer cell proliferation, migration, and invasion were also explored in vitro. The potential miR-365a-3p that targets USP33 was determined by dual luciferase reporter assay and verified by qPCR and western blot analysis. miR-365a-3p acts as an oncogene by promoting lung carcinogenesis via the downregulation of the miR-365a/USP33/SLIT2/ROBO1 axis based on western blot analysis. Subcutaneous tumourigenesis further demonstrated that miR-365a-3p promotes tumour formation in vivo. miR-365a-3p was upregulated in lung adenocarcinoma and lung cancer cell lines. Overexpression of miR-365a-3p promoted and inhibition of miR-365a-3p suppressed the proliferation, migration, and invasion of lung cancer cells. We identified USP33 as the downstream target of miR-365a-3p and observed a negative correlation between miR-365a-3p and USP33 expression in lung adenocarcinoma patients. The miR-365/USP33/SLIT2/ROBO1 axis, a new mechanism, was reported to inhibit the invasion and metastasis of lung cancer. A nude mouse model of lung cancer further verified these findings. In summary, miR-365a-3p acts as an oncogene by promoting lung carcinogenesis via the downregulation of the USP33/SLIT2/ROBO1 signalling pathway, making the miR-365/USP33/SLIT2/ROBO1 axis a new mechanism of lung cancer promotion and a novel therapeutic target for predicting prognosis and response to gene therapy.

  • MOESM4 of MicroRNA-365 promotes lung carcinogenesis by downregulating the USP33/SLIT2/ROBO1 signalling pathway
    2018
    Co-Authors: Yuhuan Wang, Shuhua Zhang, Hejing Bao, Baishen Zhang
    Abstract:

    Additional file 4: Table S1. PCR sequences of miR-365a-3p and USP33. (a) hsa-miR-365a-3p sequence. (b) USP33 3สน UTR primer sequences

  • MicroRNA-365 promotes lung carcinogenesis by downregulating the USP33/SLIT2/ROBO1 signalling pathway
    'Springer Science and Business Media LLC', 2018
    Co-Authors: Yuhuan Wang, Shuhua Zhang, Hejing Bao, Baishen Zhang
    Abstract:

    Abstract Background Abnormal microRNA expression is closely related to cancer occurrence and development. miR-365a-3p plays an oncogenic role in skin cancer, but its role in lung cancer remains unclear. In this study, we aimed to investigate its role and underlying molecular mechanisms in lung cancer. Methods Western blot and real-time quantitative PCR (qPCR) were used to detect the expression of miR-365a-3p in lung adenocarcinoma and lung cancer cell lines. The effects of miR-365a-3p on lung cancer cell proliferation, migration, and invasion were also explored in vitro. The potential miR-365a-3p that targets USP33 was determined by dual luciferase reporter assay and verified by qPCR and western blot analysis. miR-365a-3p acts as an oncogene by promoting lung carcinogenesis via the downregulation of the miR-365a/USP33/SLIT2/ROBO1 axis based on western blot analysis. Subcutaneous tumourigenesis further demonstrated that miR-365a-3p promotes tumour formation in vivo. Results miR-365a-3p was upregulated in lung adenocarcinoma and lung cancer cell lines. Overexpression of miR-365a-3p promoted and inhibition of miR-365a-3p suppressed the proliferation, migration, and invasion of lung cancer cells. We identified USP33 as the downstream target of miR-365a-3p and observed a negative correlation between miR-365a-3p and USP33 expression in lung adenocarcinoma patients. The miR-365/USP33/SLIT2/ROBO1 axis, a new mechanism, was reported to inhibit the invasion and metastasis of lung cancer. A nude mouse model of lung cancer further verified these findings. Conclusions In summary, miR-365a-3p acts as an oncogene by promoting lung carcinogenesis via the downregulation of the USP33/SLIT2/ROBO1 signalling pathway, making the miR-365/USP33/SLIT2/ROBO1 axis a new mechanism of lung cancer promotion and a novel therapeutic target for predicting prognosis and response to gene therapy

Yi Rao - One of the best experts on this subject based on the ideXlab platform.

  • Midline crossing and Slit responsiveness of commissural axons require USP33
    2016
    Co-Authors: Junichi Yuasa-kawada, Yi Rao, Mariko Kinoshita-kawada, Jane Y
    Abstract:

    Commissural axons cross the ventral midline of the neural tube in a Slit-dependent manner. The underlying molecular mechanisms remain to be elucidated. Here we report that the deubiquitinating enzyme USP33 interacts with the Robo1 receptor. USP33 is essential for midline crossing by commissural axons and for their response to Slit. Our results reveal a previously unknown role of USP33 in vertebrate commissural axon guidance and in Slit signaling. Developing axons are guided by multiple molecular cues to navigate toward their targets. Slit proteins are a family of guidance cues critical for axon pathfinding, especially, at the ventral midline of the central nervous system1–3. To identify regulatory components in the Slit-Roundabout (Robo) pathway, we searched for proteins interacting with the intracellular domain of Robo14. By screening a mouse brain cDNA library using the yeast two-hybrid strategy, we isolated multiple clones encoding ubiquitin-specific protease 33 (USP33) [also known as von Hippel-Lindau protein-interacting deubiquitinating enzyme 1 (VDU1)]5. USP33 is widely expressed in the brain and other tissues5. Our Western blotting and immunostaining experiments show that USP33 is expressed in commissural neurons of th

  • deubiquitinating enzyme USP33 vdu1 is required for slit signaling in inhibiting breast cancer cell migration
    Proceedings of the National Academy of Sciences of the United States of America, 2009
    Co-Authors: Junichi Yuasakawada, Mariko Kinoshitakawada, Yi Rao
    Abstract:

    Slit regulates migration of not only neurons, but also nonneuronal cells, such as leukocytes and cancer cells. Slit effect on cancer cell migration has not been well-characterized. In this study, we used several different assays to examine Slit effect on breast cancer cell migration in vitro. We show that ubiquitin-specific protease 33 (USP33)/VDU1, originally identified as a von Hippel-Lindau tumor suppressor (VHL) protein-interacting deubiquitinating enzyme, binds to the Robo1 receptor, and that USP33 is required for Slit responsiveness in breast cancer cells. Slit induces redistribution of Robo1 from intracellular compartments to the plasma membrane in a USP33-dependent manner. Slit impairs directional migration of breast cancer cells without affecting their migration speed. This inhibitory effect is Robo-mediated and USP33-dependent. These data uncover a previously unknown function of USP33 and reveal a new player in Slit-Robo signaling in cancer cell migration.

Shengyou Lin - One of the best experts on this subject based on the ideXlab platform.

  • Radiation Enhances the Epithelial- Mesenchymal Transition of A549 Cells via miR3591-5p/USP33/PPM1A.
    Cellular physiology and biochemistry : international journal of experimental cellular physiology biochemistry and pharmacology, 2018
    Co-Authors: Yazhen Zhong, Jian Chen, Xianlei Lin, Zechen Lin, Nan Wang, Shengyou Lin
    Abstract:

    Background/Aims: Radiotherapy plays a critical role in lung cancer treatment. Radiation can activate transforming growth factor-β (TGF-β) signaling and induce the epithelial-mesenchymal transition (EMT), which may lead to distant metastases. MicroRNAs (miRNAs) have been suggested to affect radiotherapy in lung cancer. Methods: miRNA Next-Generation Sequencing was performed to investigate the effects of irradiation on the miRNA profile of lung cancer A549 cells. The functions of identified miRNA on the radiation induced EMT and TGF-β activation in A549 cells were then explored. Protein expression was evaluated by western blotting. Immunofluorescence staining was performed to detect the localization of Snail. Luciferase Assay was used to determine the target gene regulated by the identified miRNA. Results: Radiation time-dependently induced EMT in A549 lung cancer cells as indicated by the changes of morphology, the expression of EMT marker proteins (E-cadherin, α-SMA and Vimentin) and the nuclear localization of Snail. Moreover, miR-3591-5p was identified as the most significant increased miRNA in response to radiation, and further experiments indicated that miR-3591-5p was required for radiation induced EMT and TGF-β/ Smad2/3 activation. Ubiquitin Specific Peptidase 33 (USP33) was a downstream target of miR-3591-5p as predicted by TargetScan and validated by 3’ untranslated regions (UTRs) Luciferase Assay. USP33 could deubiquitinate PPM1A (protein phosphatase, Mg2+/Mn2 + dependent 1A), a phosphatase for Smad2/3. Ectopic expression of USP33 or PPM1A partially abolished the effects of miR-3591-5p on EMT and TGF-β/ Smad2/3 activation. Conclusion: The present study revealed the critical role of miR-3591-5p/USP33/PPM1A in radiation-induced EMT via TGF-β signaling and may suggest novel radiation sensitise strategies for lung cancer.

  • radiation enhances the epithelial mesenchymal transition of a549 cells via mir3591 5p USP33 ppm1a
    Cellular Physiology and Biochemistry, 2018
    Co-Authors: Yazhen Zhong, Jian Chen, Xianlei Lin, Zechen Lin, Nan Wang, Shengyou Lin
    Abstract:

    Background/Aims: Radiotherapy plays a critical role in lung cancer treatment. Radiation can activate transforming growth factor-β (TGF-β) signaling and induce the epithelial-mesenchymal transition (EMT), which may lead to distant metastases. MicroRNAs (miRNAs) have been suggested to affect radiotherapy in lung cancer. Methods: miRNA Next-Generation Sequencing was performed to investigate the effects of irradiation on the miRNA profile of lung cancer A549 cells. The functions of identified miRNA on the radiation induced EMT and TGF-β activation in A549 cells were then explored. Protein expression was evaluated by western blotting. Immunofluorescence staining was performed to detect the localization of Snail. Luciferase Assay was used to determine the target gene regulated by the identified miRNA. Results: Radiation time-dependently induced EMT in A549 lung cancer cells as indicated by the changes of morphology, the expression of EMT marker proteins (E-cadherin, α-SMA and Vimentin) and the nuclear localization of Snail. Moreover, miR-3591-5p was identified as the most significant increased miRNA in response to radiation, and further experiments indicated that miR-3591-5p was required for radiation induced EMT and TGF-β/ Smad2/3 activation. Ubiquitin Specific Peptidase 33 (USP33) was a downstream target of miR-3591-5p as predicted by TargetScan and validated by 3’ untranslated regions (UTRs) Luciferase Assay. USP33 could deubiquitinate PPM1A (protein phosphatase, Mg2+/Mn2 + dependent 1A), a phosphatase for Smad2/3. Ectopic expression of USP33 or PPM1A partially abolished the effects of miR-3591-5p on EMT and TGF-β/ Smad2/3 activation. Conclusion: The present study revealed the critical role of miR-3591-5p/USP33/PPM1A in radiation-induced EMT via TGF-β signaling and may suggest novel radiation sensitise strategies for lung cancer.

Ursula Jakob - One of the best experts on this subject based on the ideXlab platform.

  • hsp33 confers bleach resistance by protecting elongation factor tu against oxidative degradation in vibrio cholerae
    Molecular Microbiology, 2012
    Co-Authors: Wei Yun Wholey, Ursula Jakob
    Abstract:

    Summary The redox-regulated chaperone Hsp33 protects bacteria specifically against stress conditions that cause oxidative protein unfolding, such as treatment with bleach or exposure to peroxide at elevated temperatures. To gain insight into the mechanism by which expression of Hsp33 confers resistance to oxidative protein unfolding conditions, we made use of Vibrio cholerae strain O395 lacking the Hsp33 gene hslO. We found that this strain, which is exquisitely bleach-sensitive, displays a temperature-sensitive (ts) phenotype during aerobic growth, implying that V. cholerae suffers from oxidative heat stress when cultivated at 43°C. We utilized this phenotype to select for Escherichia coli genes that rescue the ts phenotype of V. cholerae ΔhslO when overexpressed. We discovered that expression of a single protein, the elongation factor EF-Tu, was sufficient to rescue both the ts and bleach-sensitive phenotypes of V. cholerae ΔhslO. In vivo studies revealed that V. cholerae EF-Tu is highly sensitive to oxidative protein degradation in the absence of Hsp33, indicating that EF-Tu is a vital chaperone substrate of Hsp33 in V. cholerae. These results suggest an ‘essential client protein’ model for Hsp33's chaperone action in Vibrio in which stabilization of a single oxidative stress-sensitive protein is sufficient to enhance the oxidative stress resistance of the whole organism.

  • unfolding of metastable linker region is at the core of hsp33 activation as a redox regulated chaperone
    Journal of Biological Chemistry, 2010
    Co-Authors: Claudia M Cremers, Marianne Ilbert, Dana Reichmann, Jens Hausmann, Ursula Jakob
    Abstract:

    Hsp33, a molecular chaperone specifically activated by oxidative stress conditions that lead to protein unfolding, protects cells against oxidative protein aggregation. Stress sensing in Hsp33 occurs via its C-terminal redox switch domain, which consists of a zinc center that responds to the presence of oxidants and an adjacent metastable linker region, which responds to unfolding conditions. Here we show that single mutations in the N terminus of Hsp33 are sufficient to either partially (Hsp33-M172S) or completely (Hsp33-Y12E) abolish this post-translational regulation of Hsp33 chaperone function. Both mutations appear to work predominantly via the destabilization of the Hsp33 linker region without affecting zinc coordination, redox sensitivity, or substrate binding of Hsp33. We found that the M172S substitution causes moderate destabilization of the Hsp33 linker region, which seems sufficient to convert the redox-regulated Hsp33 into a temperature-controlled chaperone. The Y12E mutation leads to the constitutive unfolding of the Hsp33 linker region thereby turning Hsp33 into a constitutively active chaperone. These results demonstrate that the redox-controlled unfolding of the Hsp33 linker region plays the central role in the activation process of Hsp33. The zinc center of Hsp33 appears to act as the redox-sensitive toggle that adjusts the thermostability of the linker region to the cell redox status. In vivo studies confirmed that even mild overexpression of the Hsp33-Y12E mutant protein inhibits bacterial growth, providing important evidence that the tight functional regulation of Hsp33 chaperone activity plays a vital role in bacterial survival.

  • bleach activates a redox regulated chaperone by oxidative protein unfolding
    Cell, 2008
    Co-Authors: Jeannette Winter, Marianne Ilbert, Paul C F Graf, Dennis Ozcelik, Ursula Jakob
    Abstract:

    SUMMARY Hypochlorous acid (HOCl), the active ingredient in household bleach, is an effective antimicrobial produced by the mammalian host defense to kill invading microorganisms. Despite the widespread use of HOCl, surprisingly little is known about its mode of action. In this study, we demonstrate that low molar ratios of HOCl to protein cause oxidative protein unfolding in vitro and target thermolabile proteins for irreversible aggregation in vivo. As a defense mechanism, bacteria use the redox-regulated chaperone Hsp33, which responds to bleach treatment with the reversible oxidative unfolding of its C-terminal redox switch domain. HOCl-mediated unfolding turns inactive Hsp33 into a highly active chaperone holdase, which protects essential Escherichia coli proteins against HOCl-induced aggregation and increases bacterial HOCl resistance. Our results substantially improve our molecular understanding about HOCl’s functional mechanism. They suggest that the antimicrobial effects of bleach are largely based on HOCl’s ability to cause aggregation of essential bacterial proteins.

  • mass spectrometry unravels disulfide bond formation as the mechanism that activates a molecular chaperone
    Journal of Biological Chemistry, 2000
    Co-Authors: Stefanie Barbirz, Ursula Jakob, Michael O Glocker
    Abstract:

    Abstract The heat shock protein Hsp33 is a very potent molecular chaperone with a distinctive mode of functional regulation; its activity is redox-regulated. In its reduced form all six cysteinyl residues of Hsp33 are present as thiols, and Hsp33 displays no folding helper activity. Exposure of Hsp33 to oxidizing conditions like H2O2, however, rapidly converts Hsp33 into an efficient molecular chaperone. Activated Hsp33 binds tightly to refolding intermediates of chemically denatured luciferase and suppresses efficiently their aggregation in vitro. Matrix-assisted laser desorption/ionization-mass spectrometry peptide mapping in combination with in vitro and on target protein chemical modification showed that this activation process of Hsp33 is accompanied by the formation of two intramolecular disulfide bonds within Hsp33: Cys232—S—S—Cys234 and Cys265—S–S—Cys268. Cys141, although not involved in disulfide bond formation, was found highly reactive toward chemical modifications. In contrast, Cys239is readily accessible under reducing conditions but becomes poorly accessible though still reduced when Hsp33 is in its active state. This indicates a significant conformational change during the activation process of Hsp33. Mass spectrometry, thus, unraveled a novel molecular mechanism by which alteration of the disulfide bond structure, as a result of changes in the cellular redox potential, results in the activation of a molecular chaperone.