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Tian H, Yu D, Hu Y, Zhang P, Yang Y, Hu Q, Li M. Angiotensin II upregulates cyclophilin A by enhancing ROS production in rat cardiomyocytes. Mol Med Rep 2018; 18:4349-4355. [PMID: 30221707 PMCID: PMC6172398 DOI: 10.3892/mmr.2018.9448] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 06/15/2018] [Indexed: 12/20/2022] Open
Abstract
Angiotensin II (Ang II) is a principal molecule of the renin-angiotensin system, which promotes hypertrophy and fibrosis. It has been demonstrated that Ang II upregulates the expression of cyclophilin A (CypA), which is a potential myocardial hypertrophy factor. However, the mechanisms by which Ang II induces the expression of CypA in cardiomyocytes remain unclear. In the present study, reactive oxygen species (ROS) were detected by fluorescence microscopy, and western blot analysis and ELISA were used to measure CypA expression. It was identified that Ang II enhanced the production of ROS in rat cardiomyocytes. ROS, in turn, promoted CypA expression and secretion. Notably, the action of Ang II was primarily dependent on the angiotensin type 2 receptor (AT2R), not the type 1 receptor. These results provided an insight into the role of the AT2R signaling pathway in Ang II-induced myocardial hypertrophy.
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Affiliation(s)
- Hangyu Tian
- Key Laboratory for Animal Genetic Diversity and Evolution of High Education in Yunnan Province, School of Life Sciences, Yunnan University, Kunming, Yunnan 650091, P.R. China
| | - Dan Yu
- Key Laboratory for Animal Genetic Diversity and Evolution of High Education in Yunnan Province, School of Life Sciences, Yunnan University, Kunming, Yunnan 650091, P.R. China
| | - Yan Hu
- Key Laboratory for Animal Genetic Diversity and Evolution of High Education in Yunnan Province, School of Life Sciences, Yunnan University, Kunming, Yunnan 650091, P.R. China
| | - Pan Zhang
- Key Laboratory for Animal Genetic Diversity and Evolution of High Education in Yunnan Province, School of Life Sciences, Yunnan University, Kunming, Yunnan 650091, P.R. China
| | - Yang Yang
- Key Laboratory for Animal Genetic Diversity and Evolution of High Education in Yunnan Province, School of Life Sciences, Yunnan University, Kunming, Yunnan 650091, P.R. China
| | - Qiang Hu
- Department of Emergency Medicine, The Second Affiliated Hospital, Kunming Medical University, Kunming, Yunnan 650101, P.R. China
| | - Ming Li
- Key Laboratory for Animal Genetic Diversity and Evolution of High Education in Yunnan Province, School of Life Sciences, Yunnan University, Kunming, Yunnan 650091, P.R. China
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Ronnebaum SM, Patterson C, Schisler JC. Minireview: hey U(PS): metabolic and proteolytic homeostasis linked via AMPK and the ubiquitin proteasome system. Mol Endocrinol 2014; 28:1602-15. [PMID: 25099013 DOI: 10.1210/me.2014-1180] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
One of the master regulators of both glucose and lipid cellular metabolism is 5'-AMP-activated protein kinase (AMPK). As a metabolic pivot that dynamically responds to shifts in nutrient availability and stress, AMPK dysregulation is implicated in the underlying molecular pathology of a variety of diseases, including cardiovascular diseases, diabetes, cancer, neurological diseases, and aging. Although the regulation of AMPK enzymatic activity by upstream kinases is an active area of research, less is known about regulation of AMPK protein stability and activity by components of the ubiquitin-proteasome system (UPS), the cellular machinery responsible for both the recognition and degradation of proteins. Furthermore, there is growing evidence that AMPK regulates overall proteasome activity and individual components of the UPS. This review serves to identify the current understanding of the interplay between AMPK and the UPS and to promote further exploration of the relationship between these regulators of energy use and amino acid availability within the cell.
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Affiliation(s)
- Sarah M Ronnebaum
- McAllister Heart Institute (S.M.R., J.C.S.) and Department of Pharmacology (J.C.S.), The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599; and Presbyterian Hospital/Weill-Cornell Medical Center (C.P.), New York, New York 10065
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Wang H, Liu XB, Chen JH, Wang QQ, Chen JP, Xu JF, Sheng CY, Ni QC. Decreased expression and prognostic role of cytoplasmic BRSK1 in human breast carcinoma: correlation with Jab1 stability and PI3K/Akt pathway. Exp Mol Pathol 2014; 97:191-201. [PMID: 25036402 DOI: 10.1016/j.yexmp.2014.07.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Revised: 06/30/2014] [Accepted: 07/15/2014] [Indexed: 01/23/2023]
Abstract
OBJECTIVE Jun activation domain-binding protein 1 (Jab1) was overexpressed in breast cancer, which was involved in degradation of the cyclin-dependent kinase inhibitor p27(Kip1). The objective of this study was to examine the effect of brain specific kinase 1 (BRSK1) expression on Jab1 over-expression and related signaling pathway in breast cancer. METHODS Immunohistochemical analysis was performed in 95 human breast carcinoma samples and the data were correlated with clinicopathologic features. Furthermore, Western blot analysis was performed for BRSK1 and Jab1 in breast carcinoma samples and cell lines to evaluate their protein levels and molecular interaction. RESULTS We found that the cytoplasmic BRSK1 expression was inversely associated with Jab1 expression (P<0.01) and correlated significantly with histologic grade (P=0.006), however nuclear BRSK1 expression couldn't obtain similar results. Kaplan-Meier analysis revealed that survival curves of low versus high expressers of cytoplasmic BRSK1 and Jab1 showed a highly significant separation in breast cancer (P<0.01). While in vitro, following release of breast cancer cell lines from serum starvation, the expression of Jab1, phosphor-Akt (p-Akt) was up-regulated, whereas BRSK1 and p27(Kip1) were decreased. Treatment of phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 could diminish Jab1 expression but increase BRSK1 expression. In addition, we employed siRNA technique to knock down Jab1 and/or BRSK1 expression and observed their effects on MDA-MB-231 cell growth. CONCLUSIONS BRSK1 is a novel tumor suppressor in breast cancer which inversely correlated with Jab1 expression, may involve in the restoring Jab1-induced suppression of p27(Kip1) and may regulate cell cycle through the PI3K/Akt pathway.
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Affiliation(s)
- Hua Wang
- Department of General Surgery, the Affiliated Hospital of Nantong University, Medical College of Nantong University, Nantong 226001, Jiangsu, PR China
| | - Xiao-Bing Liu
- Department of General Surgery, the Affiliated Hospital of Nantong University, Medical College of Nantong University, Nantong 226001, Jiangsu, PR China
| | - Jia-Hui Chen
- Department of Neurology, Affiliated Hospital of Nantong University, Medical College of Nantong University, Nantong 226001, Jiangsu, PR China
| | - Qing-Qing Wang
- Department of General Surgery, the Affiliated Hospital of Nantong University, Medical College of Nantong University, Nantong 226001, Jiangsu, PR China
| | - Jin-Peng Chen
- Department of General Surgery, the Affiliated Hospital of Nantong University, Medical College of Nantong University, Nantong 226001, Jiangsu, PR China
| | - Jun-Fei Xu
- Department of General Surgery, the Affiliated Hospital of Nantong University, Medical College of Nantong University, Nantong 226001, Jiangsu, PR China
| | - Chen-Yi Sheng
- Department of General Surgery, the Affiliated Hospital of Nantong University, Medical College of Nantong University, Nantong 226001, Jiangsu, PR China
| | - Qi-Chao Ni
- Department of General Surgery, the Affiliated Hospital of Nantong University, Medical College of Nantong University, Nantong 226001, Jiangsu, PR China.
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Porcine JAB1 significantly enhances apoptosis induced by staurosporine. Cell Death Dis 2013; 4:e823. [PMID: 24091666 PMCID: PMC3824667 DOI: 10.1038/cddis.2013.357] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 08/08/2013] [Accepted: 08/12/2013] [Indexed: 01/18/2023]
Abstract
c-Jun activation domain-binding protein-1 (JAB1), also known as the subunit 5 of the COP9 signalosome, is a multifunctional protein that regulates cell proliferation, apoptosis and oncogenesis by interacting with and subsequently degrading a large number of proteins. Although human JAB1 (hJAB1) has been studied for a long time, studies on porcine JAB1 (pJAB1) have never been reported. In the present study, we cloned and characterized the pJAB1 gene. The genomic structure of the pJAB1 gene was determined. The open-reading frame of pJAB1 encoded 334 amino acids. The deduced amino acid sequence was highly similar to homologs in other species. Furthermore, the tertiary structure analysis and phylogenetic analysis indicated that JAB1 was highly conservative among species. pJAB1 may interact with several proteins according to protein–protein interactions analysis. In addition, pJAB1 was found to be universally expressed in porcine tissues. Subcellular localization analysis showed that GFP–pJAB1 fusion protein distributed specifically in the cytoplasm. Flow cytometric analysis proved that pJAB1 significantly enhanced apoptosis induced by staurosporine, which at least partially depended on the activation of caspase-9 and caspase-3. This study is useful for understanding the function of pJAB1 and offers a potential molecular model for the investigation of diseases related to hJAB1.
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Wang H, Dey D, Carrera I, Minond D, Bianchi E, Xu S, Lakshmana MK. COPS5 (Jab1) protein increases β site processing of amyloid precursor protein and amyloid β peptide generation by stabilizing RanBP9 protein levels. J Biol Chem 2013; 288:26668-77. [PMID: 23926111 DOI: 10.1074/jbc.m113.476689] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Increased processing of amyloid precursor protein (APP) and accumulation of neurotoxic amyloid β peptide (Aβ) in the brain is central to the pathogenesis of Alzheimer's disease (AD). Therefore, the identification of molecules that regulate Aβ generation is crucial for future therapeutic approaches for AD. We demonstrated previously that RanBP9 regulates Aβ generation in a number of cell lines and primary neuronal cultures by forming tripartite protein complexes with APP, low-density lipoprotein-related protein, and BACE1, consequently leading to increased amyloid plaque burden in the brain. RanBP9 is a scaffold protein that exists and functions in multiprotein complexes. To identify other proteins that may bind RanBP9 and regulate Aβ levels, we used a two-hybrid analysis against a human brain cDNA library and identified COPS5 as a novel RanBP9-interacting protein. This interaction was confirmed by coimmunoprecipitation experiments in both neuronal and non-neuronal cells and mouse brain. Colocalization of COPS5 and RanBP9 in the same subcellular compartments further supported the interaction of both proteins. Furthermore, like RanBP9, COPS5 robustly increased Aβ generation, followed by increased soluble APP-β (sAPP-β) and decreased soluble-APP-α (sAPP-α) levels. Most importantly, down-regulation of COPS5 by siRNAs reduced Aβ generation, implying that endogenous COPS5 regulates Aβ generation. Finally, COPS5 levels were increased significantly in AD brains and APΔE9 transgenic mice, and overexpression of COPS5 strongly increased RanBP9 protein levels by increasing its half-life. Taken together, these results suggest that COPS5 increases Aβ generation by increasing RanBP9 levels. Thus, COPS5 is a novel RanBP9-binding protein that increases APP processing and Aβ generation by stabilizing RanBP9 protein levels.
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APC/C(Cdh1) targets brain-specific kinase 2 (BRSK2) for degradation via the ubiquitin-proteasome pathway. PLoS One 2012; 7:e45932. [PMID: 23029325 PMCID: PMC3448725 DOI: 10.1371/journal.pone.0045932] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 08/23/2012] [Indexed: 11/19/2022] Open
Abstract
Studies of brain-specific kinase 2 (BRSK2), an AMP-activated protein kinase (AMPK)-related kinase, and its homologs suggest that they are multifunctional regulators of cell-cycle progression. BRSK2, which contains a ubiquitin-associated (UBA) domain, is polyubiquitinated in cells. However, the regulatory mechanisms and exact biological function of BRSK2 remain unclear. Herein, we show that BRSK2 co-localizes with the centrosomes during mitosis. We also demonstrate that BRSK2 protein levels fluctuate during the cell cycle, peaking during mitosis and declining in G1 phase. Furthermore, Cdh1, rather than Cdc20, promotes the degradation of BRSK2 in vivo. Consistent with this finding, knock-down of endogenous Cdh1 blocks BRSK2 degradation during the G1 phase. The conserved KEN box of BRSK2 is required for anaphase-promoting complex/cyclosome-Cdh1 (APC/CCdh1)-dependent degradation. Additionally, overexpression of either BRSK2(WT) or BRSK2(ΔKEN) increases the percentage of cells in G2/M. Thus, our results provide the first evidence that BRSK2 regulates cell-cycle progression controlled by APC/CCdh1 through the ubiquitin-proteasome pathway.
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Wang Y, Wan B, Li D, Zhou J, Li R, Bai M, Chen F, Yu L. BRSK2 is regulated by ER stress in protein level and involved in ER stress-induced apoptosis. Biochem Biophys Res Commun 2012; 423:813-8. [PMID: 22713462 DOI: 10.1016/j.bbrc.2012.06.046] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Accepted: 06/11/2012] [Indexed: 12/29/2022]
Abstract
The accumulation of unfolded protein in lumen of the endoplasmic reticulum (ER) triggers a cell stress response called ER stress, which induces the transcriptional up-regulation of a number of proteins, including molecular chaperones and folding enzymes, the global inhibition of protein synthesis, and the activation of apoptotic pathways. The molecular mechanism underlying the apoptotic response has remained largely elusive. AMP activated protein kinase (AMPK) has been implicated in ER stress-induced apoptosis through its role in attenuating ER stress. BRSK2 (brain selective kinase 2, also known as SAD-A) is a serine/threonine kinase of the AMPK family. Here, we demonstrate that the BRSK2 protein levels are significantly down-regulated in response to ER stress in PANC-1 and HeLa cells. Furthermore, we also observed that ER stress induces endogenous BRSK2 to localize to the ER. Importantly, knockdown of endogenous BRSK2 expression enhances ER stress-mediated apoptosis in cells while over express BRSK2 in wild type or kinase-dead type both reduce the apoptosis. BRSK2 knockdown increases the transcription of CHOP and the levels of cleaved caspase-3 in cells in response to ER stress while over expression of BRSK2 decrease CHOP mRNA and levels of cleaved caspase-3. Taken together, our findings demonstrate ER stress may reduce BRSK2 protein and change BRSK2 subcellular localization, which in turn alleviate ER stress-induced apoptosis.
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Affiliation(s)
- Yingli Wang
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, 220 Handan Road, Shanghai, PR China
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