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Wu CHY, Chan JYH, Chou JLJ, Chan SHH, Chang AYW. Engagement of ubiquitination and de-ubiquitination at rostral ventrolateral medulla in experimental brain death. J Biomed Sci 2012; 19:48. [PMID: 22545670 PMCID: PMC3410792 DOI: 10.1186/1423-0127-19-48] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 04/30/2012] [Indexed: 01/12/2023] Open
Abstract
Background Whereas brain death is a vitally important clinical phenomenon, our contemporary understanding on its underlying cellular mechanisms remains elusive. This study evaluated whether the ubiquitin-proteasome system (UPS) in the rostral ventrolateral medulla (RVLM), a neural substrate that our laboratory identified previously to be intimately related to brain death, is engaged in this fatal process. Methods We performed proteomics, Western Blot, real-time PCR, ELISA and pharmacological experiments in conjunction with a clinically relevant experimental endotoxemia model of brain death based on intravenous administration of Escherichia coli lipopolysaccharide in adult male Sprague–Dawley rats. Results Proteomics, Western blot and enzyme activity analyses demonstrated that polyubiquitination was preserved and de-ubiquitination by ubiquitin C-terminal hydrolase isozyme-L1 (UCH-L1) was sustained, alongside increased monoubiquitin availability or proteasome activity in RVLM over the course of experimental endotoxemia. However, real-time PCR revealed no significant alteration in proteasome subunit alpha type-1, ubiquitin or UCH-L1 at mRNA level. Functionally, whereas microinjection into the bilateral RVLM of proteasome inhibitors (lactacystin or proteasome inhibitor II) potentiated survival, an inhibitor of ubiquitin-recycling (ubiquitin aldehyde) or an UCH-L1 inhibitor exacerbated mortality. Conclusions We proposed previously that the progression towards brain death entails a tug-of-war between pro-death and pro-life programs in RVLM. It is conceivable that ubiquitination or de-ubiquitination in RVLM participate in brain death by regulating the degradation of the proteins involved in those programs.
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Affiliation(s)
- Carol H Y Wu
- Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, 83301, Taiwan, Republic of China
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152
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Shoji I. Roles of the two distinct proteasome pathways in hepatitis C virus infection. World J Virol 2012; 1:44-50. [PMID: 24175210 PMCID: PMC3782266 DOI: 10.5501/wjv.v1.i2.44] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 02/22/2012] [Accepted: 03/05/2012] [Indexed: 02/05/2023] Open
Abstract
Hepatitis C virus (HCV) infection often causes chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. The development of a HCV cell culture system enabled us to investigate its whole HCV life cycle and develop a better understanding of the pathogenesis of this virus. Post-translational modification plays a crucial role in HCV replication and in the maturation of viral particles. There is growing evidence also suggesting that the ubiquitin-proteasome pathway and the ubiquitin-independent proteasome pathway are involved in the stability control of HCV proteins. Many viruses are known to manipulate the proteasome pathways to modulate the cell cycle, inhibit apoptosis, evade the immune system, and activate cell signaling, thereby contributing to persistent infection and viral carcinogenesis. The identification of functional interactions between HCV and the proteasome pathways will therefore shed new light on the life cycle and pathogenesis of HCV. This review summarizes the current knowledge on the involvement of the ubiquitin-dependent and -independent proteasome pathways in HCV infection and discusses the roles of these two distinct mechanisms in HCV pathogenesis.
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Affiliation(s)
- Ikuo Shoji
- Ikuo Shoji, Division of Microbiology, Kobe University Graduate School of Medicine, Hyogo 650-0017, Japan
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153
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Proteasome inhibitor bortezomib ameliorates intestinal injury in mice. PLoS One 2012; 7:e34587. [PMID: 22479648 PMCID: PMC3316702 DOI: 10.1371/journal.pone.0034587] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2011] [Accepted: 03/07/2012] [Indexed: 12/16/2022] Open
Abstract
Background Bortezomib is a proteasome inhibitor that has shown impressive efficacy in the treatment of multiple myeloma. In mice, the addition of dextran sulfate sodium (DSS) to drinking water leads to acute colitis that can serve as an experimental animal model for human ulcerative colitis. Methodology/Principal Findings Bortezomib treatment was shown to potently inhibit murine DSS-induced colitis. The attenuation of DSS-induced colitis was associated with decreased inflammatory cell infiltration in the colon. Specifically, bortezomib-treated mice showed significantly decreased numbers of CD4+ and CD8+ T cells in the colon and mesenteric lymph nodes. Bortezomib treatment significantly diminished interferon (IFN)-γ expression in the colon and mesenteric lymph nodes. Furthermore, cytoplasmic IFN-γ production by CD4+ and CD8+ T cells in mesenteric lymph nodes was substantially decreased by bortezomib treatment. Notably, bortezomib enhanced T cell apoptosis by inhibiting nuclear factor-κB activation during DSS-induced colitis. Conclusions/Significance Bortezomib treatment is likely to induce T cell death, thereby suppressing DSS-induced colitis by reducing IFN-γ production.
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154
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Targeting the ubiquitin–proteasome pathway with inorganic compounds to fight cancer: a challenge for the future. Future Med Chem 2012; 4:525-43. [DOI: 10.4155/fmc.11.187] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Proteasomes are large multicatalytic complexes endowed with proteinase activity, located both in the cytosol and in the nucleus of eukaryotic cells. The ubiquitin–proteasome system is responsible for selective degradation of most intracellular proteins and therefore plays an essential regulatory role in many critical cellular processes. The proteasomal activity can also contribute to the pathological states of many diseases, including inflammation, neurodegeneration and cancer, through a disregulation in the level of regulatory proteins. These diseases may be targeted by modulating components of the ubiquitin–proteasome pathway, using small molecules as inhibitors. Bortezomib (Velcade®), used for the treatment of relapsed multiple myeloma, is the first and, up to now, the only proteasome inhibitor approved by the US FDA. Nowadays, the discovery that some metal-based complexes exert their antiproliferative action by affecting proteasomal activities provides the possibility of developing new opportunities in cancer therapy.
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155
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Ge Y, Kazi A, Marsilio F, Luo Y, Jain S, Brooks W, Daniel KG, Guida WC, Sebti SM, Lawrence HR. Discovery and synthesis of hydronaphthoquinones as novel proteasome inhibitors. J Med Chem 2012; 55:1978-98. [PMID: 22220566 DOI: 10.1021/jm201118h] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Screening efforts led to the identification of PI-8182 (1), an inhibitor of the chymotrypsin-like (CT-L) activity of the proteasome. Compound 1 contains a hydronaphthoquinone pharmacophore with a thioglycolic acid side chain at position 2 and thiophene sulfonamide at position 4. An efficient synthetic route to the hydronaphthoquinone sulfonamide scaffold was developed, and compound 1 was synthesized in-house to confirm the structure and activity (IC(50) = 3.0 ± 1.6 μM [n = 25]). Novel hydronaphthoquinone derivatives of 1 were designed, synthesized, and evaluated as proteasome inhibitors. The structure-activity relationship (SAR) guided synthesis of more than 170 derivatives revealed that the thioglycolic acid side chain is required and the carboxylic acid group of this side chain is critical to the CT-L inhibitory activity of compound 1. Furthermore, replacement of the carboxylic acid with carboxylic acid isosteres such as tetrazole or triazole greatly improves potency. Compounds with a thio-tetrazole or thio-triazole side chain in position 2, where the thiophene was replaced by hydrophobic aryl moieties, were the most active compounds with up to 20-fold greater CT-L inhibition than compound 1 (compounds 15e, 15f, 15h, 15j, IC(50) values around 200 nM, and compound 29, IC(50) = 150 nM). The synthetic iterations described here not only led to improving potency in vitro but also resulted in the identification of compounds that are more active such as 39 (IC(50) = 0.44 to 1.01 μM) than 1 (IC(50) = 3.54 to 7.22 μM) at inhibiting the proteasome CT-L activity in intact breast cancer cells. Treatment with 39 also resulted in the accumulation of ubiquitinated cellular proteins and inhibition of tumor cell proliferation of breast cancer cells. The hit 1 and its analogue 39 inhibited proteasome CT-L activity irreversibly.
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Affiliation(s)
- Yiyu Ge
- Drug Discovery Department, Moffitt Cancer Center, 12902 Magnolia Drive, Tampa, Florida 33612, USA
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156
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Tanaka T, Nakatani T, Kamitani T. Inhibition of NEDD8-conjugation pathway by novel molecules: potential approaches to anticancer therapy. Mol Oncol 2012; 6:267-75. [PMID: 22306028 DOI: 10.1016/j.molonc.2012.01.003] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 01/08/2012] [Accepted: 01/09/2012] [Indexed: 11/25/2022] Open
Abstract
Cancer cells can survive through the upregulation of cell cycle and the escape from apoptosis induced by numerous cellular stresses. In the normal cells, these biological cascades depend on scheduled proteolytic degradation of regulatory proteins via the ubiquitin-proteasome pathway. Therefore, interruption of regulated proteolytic pathways leads to abnormal cell-proliferation. Ubiquitin ligases called SCF complex (consisting of Skp-1, cullin, and F-box protein) or CRL (cullin-RING ubiquitin ligase) are predominant in a family of E3 ubiquitin ligases that control a final step in ubiquitination of diverse substrates. To a great extent, the ubiquitin ligase activity of the SCF complex requires the conjugation of NEDD8 to cullins, i.e. scaffold proteins. This review is anticipated to review the downregulation system of NEDD8 conjugation by several factors including a chemical compound such as MLN4924 and protein molecules (e.g. COP9 signalosome, inactive mutant of Ubc12, and NUB1/NUB1L). Since the downregulation of NEDD8 conjugation affects cell-cycle progression by inhibiting the ligase activity of SCF complexes, such knowledge in the NEDD8-conjugation pathway will contribute to the more magnificent therapies that selectively suppress tumorigenesis.
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Affiliation(s)
- Tomoaki Tanaka
- Department of Urology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abenoku, Osaka 545-8585, Japan.
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157
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Bornstein B, Edison N, Gottfried Y, Lev T, Shekhtman A, Gonen H, Rajalingam K, Larisch S. X-linked Inhibitor of Apoptosis Protein promotes the degradation of its antagonist, the pro-apoptotic ARTS protein. Int J Biochem Cell Biol 2011; 44:489-95. [PMID: 22185822 DOI: 10.1016/j.biocel.2011.12.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 11/24/2011] [Accepted: 12/06/2011] [Indexed: 02/07/2023]
Abstract
ARTS (Sept4_i2) is a mitochondrial pro-apoptotic tumor suppressor protein. In response to apoptotic signals, ARTS translocates to the cytosol where it promotes caspase activation through caspase de-repression and proteasome mediated degradation of X-linked Inhibitor of Apoptosis Protein (XIAP). Here we show that XIAP regulates the levels of ARTS by serving as its ubiquitin ligase, thereby providing a potential feedback mechanism to protect against unwanted apoptosis. Using both in vitro and in vivo ubiquitination assays we found that ARTS is directly ubiquitinated by XIAP. Moreover, we found that XIAP-induced ubiquitination and degradation is prevented by removal of the first four amino acids in the N-terminus of ARTS, which contains a single lysine residue at position 3. Thus, this lysine at position 3 is a likely target for ubiquitination by XIAP. Importantly, although the stabilized ARTS lacking its first 4 residues binds XIAP as well as the full length ARTS, it is more potent in promoting apoptosis than the full length ARTS. This suggests that increased stability of ARTS has a significant effect on its ability to induce apoptosis. Collectively, our data reveal a mutual regulatory mechanism by which ARTS and XIAP control each other's levels through the ubiquitin proteasome system.
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Affiliation(s)
- Bavat Bornstein
- Cell Death Research Laboratory, Department of Biology, Faculty of Natural Sciences, University of Haifa, Mount Carmel, Haifa 31905, Israel
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158
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Wu CHY, Chan JYH, Chan SHH, Chang AYW. A double-edged sword role for ubiquitin-proteasome system in brain stem cardiovascular regulation during experimental brain death. PLoS One 2011; 6:e27404. [PMID: 22110641 PMCID: PMC3215722 DOI: 10.1371/journal.pone.0027404] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 10/16/2011] [Indexed: 12/02/2022] Open
Abstract
Background Brain stem cardiovascular regulatory dysfunction during brain death is underpinned by an upregulation of nitric oxide synthase II (NOS II) in rostral ventrolateral medulla (RVLM), the origin of a life-and-death signal detected from blood pressure of comatose patients that disappears before brain death ensues. Furthermore, the ubiquitin-proteasome system (UPS) may be involved in the synthesis and degradation of NOS II. We assessed the hypothesis that the UPS participates in brain stem cardiovascular regulation during brain death by engaging in both synthesis and degradation of NOS II in RVLM. Methodology/Principal Findings In a clinically relevant experimental model of brain death using Sprague-Dawley rats, pretreatment by microinjection into the bilateral RVLM of proteasome inhibitors (lactacystin or proteasome inhibitor II) antagonized the hypotension and reduction in the life-and-death signal elicited by intravenous administration of Escherichia coli lipopolysaccharide (LPS). On the other hand, pretreatment with an inhibitor of ubiquitin-recycling (ubiquitin aldehyde) or ubiquitin C-terminal hydrolase isozyme L1 (UCH-L1) potentiated the elicited hypotension and blunted the prevalence of the life-and-death signal. Real-time polymerase chain reaction, Western blot, electrophoresis mobility shift assay, chromatin immunoprecipitation and co-immunoprecipitation experiments further showed that the proteasome inhibitors antagonized the augmented nuclear presence of NF-κB or binding between NF-κB and nos II promoter and blunted the reduced cytosolic presence of phosphorylated IκB. The already impeded NOS II protein expression by proteasome inhibitor II was further reduced after gene-knockdown of NF-κB in RVLM. In animals pretreated with UCH-L1 inhibitor and died before significant increase in nos II mRNA occurred, NOS II protein expression in RVLM was considerably elevated. Conclusions/Significance We conclude that UPS participates in the defunct and maintained brain stem cardiovascular regulation during experimental brain death by engaging in both synthesis and degradation of NOS II at RVLM. Our results provide information on new therapeutic initiatives against this fatal eventuality.
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Affiliation(s)
- Carol H. Y. Wu
- Center for Translation Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Taiwan, Republic of China
- Institute of Biomedical Sciences, National Sun Yat-sen University, Taiwan, Republic of China
| | - Julie Y. H. Chan
- Center for Translation Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Taiwan, Republic of China
| | - Samuel H. H. Chan
- Center for Translation Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Taiwan, Republic of China
- * E-mail: (AYWC); (SHHC)
| | - Alice Y. W. Chang
- Center for Translation Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Taiwan, Republic of China
- * E-mail: (AYWC); (SHHC)
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159
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Soucy TA, Dick LR, Smith PG, Milhollen MA, Brownell JE. The NEDD8 Conjugation Pathway and Its Relevance in Cancer Biology and Therapy. Genes Cancer 2011; 1:708-16. [PMID: 21779466 DOI: 10.1177/1947601910382898] [Citation(s) in RCA: 171] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Cancer cells depend on signals that promote cell cycle progression and prevent programmed cell death that would otherwise result from cumulative, aberrant stress. These activities require the temporally controlled destruction of specific intracellular proteins by the ubiquitin-proteasome system (UPS). To a large extent, the control points in this process include a family of E3 ubiquitin ligases called cullin-RING ligases (CRLs). The ligase activity of these multicomponent complexes requires modification of the cullin protein situated at their core with a ubiquitin-like protein called NEDD8. Neddylation results in conformational rearrangements within the CRL, which are necessary for ubiquitin transfer to a substrate. The NEDD8 pathway thus has a critical role in mediating the ubiquitination of numerous CRL substrate proteins involved in cell cycle progression and survival including the DNA replication licensing factor Cdt-1, the NF-κB transcription factor inhibitor pIκBα, and the cell cycle regulators cyclin E and p27. The initial step required for attachment of NEDD8 to a cullin is catalyzed by the E1, NEDD8-activating enzyme (NAE). The first-in-class inhibitor of NAE, MLN4924, has been shown to block the activity of NAE and prevent the subsequent neddylation of cullins. Preclinical studies have demonstrated antitumor activity in various solid tumors and hematological malignancies, and preliminary clinical data have shown the anticipated pharmacodynamic effects in humans. Here, we review the NEDD8 pathway, its importance in cancer, and the therapeutic potential of NAE inhibition.
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160
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Lee EC, Fitzgerald M, Bannerman B, Donelan J, Bano K, Terkelsen J, Bradley DP, Subakan O, Silva MD, Liu R, Pickard M, Li Z, Tayber O, Li P, Hales P, Carsillo M, Neppalli VT, Berger AJ, Kupperman E, Manfredi M, Bolen JB, Van Ness B, Janz S. Antitumor activity of the investigational proteasome inhibitor MLN9708 in mouse models of B-cell and plasma cell malignancies. Clin Cancer Res 2011; 17:7313-23. [PMID: 21903769 DOI: 10.1158/1078-0432.ccr-11-0636] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE The clinical success of the first-in-class proteasome inhibitor bortezomib (VELCADE) has validated the proteasome as a therapeutic target for treating human cancers. MLN9708 is an investigational proteasome inhibitor that, compared with bortezomib, has improved pharmacokinetics, pharmacodynamics, and antitumor activity in preclinical studies. Here, we focused on evaluating the in vivo activity of MLN2238 (the biologically active form of MLN9708) in a variety of mouse models of hematologic malignancies, including tumor xenograft models derived from a human lymphoma cell line and primary human lymphoma tissue, and genetically engineered mouse (GEM) models of plasma cell malignancies (PCM). EXPERIMENTAL DESIGN Both cell line-derived OCI-Ly10 and primary human lymphoma-derived PHTX22L xenograft models of diffuse large B-cell lymphoma were used to evaluate the pharmacodynamics and antitumor effects of MLN2238 and bortezomib. The iMyc(Cα)/Bcl-X(L) GEM model was used to assess their effects on de novo PCM and overall survival. The newly developed DP54-Luc-disseminated model of iMyc(Cα)/Bcl-X(L) was used to determine antitumor activity and effects on osteolytic bone disease. RESULTS MLN2238 has an improved pharmacodynamic profile and antitumor activity compared with bortezomib in both OCI-Ly10 and PHTX22L models. Although both MLN2238 and bortezomib prolonged overall survival, reduced splenomegaly, and attenuated IgG2a levels in the iMyc(Cα)/Bcl-X(L) GEM model, only MLN2238 alleviated osteolytic bone disease in the DP54-Luc model. CONCLUSIONS Our results clearly showed the antitumor activity of MLN2238 in a variety of mouse models of B-cell lymphoma and PCM, supporting its clinical development. MLN9708 is being evaluated in multiple phase I and I/II trials.
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Affiliation(s)
- Edmund C Lee
- Millennium Pharmaceuticals, Inc., Cambridge, Massachusetts, USA.
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Nagashima Y, Kowa H, Tsuji S, Iwata A. FAT10 protein binds to polyglutamine proteins and modulates their solubility. J Biol Chem 2011; 286:29594-600. [PMID: 21757738 DOI: 10.1074/jbc.m111.261032] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Expansion of polyglutamine (pQ) chain by expanded CAG repeat causes dominantly inherited neurodegeneration such as Huntington disease, dentatorubral-pallidoluysian atrophy (DRPLA), and numbers of other spinocerebellar ataxias. Expanded pQ disrupts the stability of the pQ-harboring protein and increases its susceptibility to aggregation. Aggregated pQ protein is recognized by the ubiquitin proteasome system, and the enzyme ubiquitin ligase covalently attaches ubiquitin, which serves as a degradation signal by the proteasome. However, accumulation of the aggregated proteins in the diseased brain suggests insufficient degradation machinery. Ubiquitin has several functionally related proteins that are similarly attached to target proteins through its C terminus glycine residue. They are called ubiquitin-like molecules, and some of them are similarly related to the protein degradation pathway. One of the ubiquitin-like molecules, FAT10, is known to accelerate protein degradation through a ubiquitin-independent manner, but its role in pQ aggregate degradation is completely unknown. Thus we investigated its role in a Huntington disease cellular model and found that FAT10 molecules were covalently attached to huntingtin through their C terminus glycine. FAT10 binds preferably to huntingtin with a short pQ chain and completely aggregated huntingtin was FAT10-negative. In addition, ataxin-1,3 and DRPLA proteins were both positive for FAT10, and aggregation enhancement was observed upon FAT10 knockdown. These findings were similar to those for huntingtin. Our new finding will provide a new role for FAT10 in the pathogenesis of polyglutamine diseases.
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Affiliation(s)
- Yu Nagashima
- Department of Molecular Neuroscience on Neurodegeneration, University of Tokyo, Tokyo, Japan
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162
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Wang H, Lai YJ, Chan YL, Li TL, Wu CJ. Epigallocatechin-3-gallate effectively attenuates skeletal muscle atrophy caused by cancer cachexia. Cancer Lett 2011; 305:40-9. [PMID: 21397390 DOI: 10.1016/j.canlet.2011.02.023] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 02/15/2011] [Accepted: 02/16/2011] [Indexed: 10/18/2022]
Abstract
Cachexia, also known as wasting syndrome notably with skeletal muscle atrophy, costs nearly one-third of all cancer deaths in man. (-)-Epigallocatechin-3-gallate (EGCG), the principal polyphenolic component in green tea, is a potent preventive against cachexia as well as cancers. However, how EGCG counteracts cachexia-provoked muscle wasting is unclear. EGCG was demonstrated to be able to retard tumor progression as well as to prevent body weight from loss, because EGCG attenuates skeletal muscle leukocytic infiltration and down-regulates tumor-induced NF-κB and E3-ligases in muscle. In mice, the dosages optimized against cachexia were determined to be 0.2 mg/mouse/day for prevention and to be 0.6 mg/mouse/day for treatment. Anti-cachexia effects were assessed using the LLC tumor model. Mice with the same body weight were divided into groups, including control, tumor bearing, and tumor-bearing but receiving water or EGCG in both prevention and treatment experiments. RT-PCR was used to assess mRNA expressions of NF-κB, MuRF 1, and MAFbx. The intracellular NF-κB, MuRF 1 and MAFbx were determined and quantified by immunofluorescence and Western blotting, respectively. Our results conclude EGCG regulates the expressions of NF-κB as well as downstream mediators, MuRF 1 and MAFbx, so EGCG may be an appropriate agent to be included in ensemble therapeutics of the tumor-induced muscle atrophy.
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Affiliation(s)
- Hang Wang
- Department of Food Science, National Taiwan Ocean University, Keelung, Taiwan
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163
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Wen H, Kim N, Fuentes EJ, Mallinger A, Gonzalez-Alegre P, Glenn KA. FBG1 is a promiscuous ubiquitin ligase that sequesters APC2 and causes S-phase arrest. Cell Cycle 2011; 9:4506-17. [PMID: 21135578 DOI: 10.4161/cc.9.22.13743] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
During cell proliferation, protein degradation is strictly regulated by the cell cycle and involves two complementary ubiquitin ligase complexes, the SCF (Skp, Cullin, F-box) and APC/C (Anaphase Promoting Complex/Cyclosome) ubiquitin ligases. SCF ligases are constitutively active and generally target only proteins after they have been selected for degradation, usually by phosphorylation. In contrast, APC/C complexes are themselves activated by phosphorylation and their substrates contain a targeting signal known as degron, a consensus amino acid sequence such as a D-Box. SCF complexes degrade proteins during the G1 phase. However, as DNA synthesis begins, the SCF complexes are degraded and APC/C complexes are activated. APC-2, a protein crucial to cell division, initiates anaphase by triggering the degradation of multiple proteins. This study explores an unexpected interaction between APC-2 and SCFFBG1. We found that FBG1 is a promiscuous ubiquitin ligase with many partners. Immunoprecipitation experiments demonstrate that FBG1 and APC2 interact directly. Mutagenesis-based experiments show that this interaction requires a D-Box found within the FBG1 F-box domain. Unexpectedly, we demonstrate that co-expression with FBG1 increases total APC2 levels. However, free APC2 is decreased, inhibiting cell proliferation. Finally, FACS analysis of cell populations expressing different forms of FBG1 demonstrate that this ubiquitin ligase induces S-phase arrest, illustrating the functional consequences of the interaction described. In summary, we have discovered a novel APC2 inhibitory activity of FBG1 independent from its function as ubiquitin ligase, providing the basis for future studies of FBG1 in aging and cancer.
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Affiliation(s)
- Hsiang Wen
- Department of Internal Medicine, Roy and Lucille A. Carver College of Medicine, Iowa City, USA
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164
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Kumar S, Kumar S, Rajendran M, Alam SM, Lin FF, Cheng PW, Lin MF. Steroids up-regulate p66Shc longevity protein in growth regulation by inhibiting its ubiquitination. PLoS One 2011; 6:e15942. [PMID: 21264241 PMCID: PMC3021521 DOI: 10.1371/journal.pone.0015942] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Accepted: 11/30/2010] [Indexed: 11/18/2022] Open
Abstract
Background p66Shc, an isoform of Shc adaptor proteins, mediates diverse signals, including cellular stress and mouse longevity. p66Shc protein level is elevated in several carcinomas and steroid-treated human cancer cells. Several lines of evidence indicate that p66Shc plays a critical role in steroid-related carcinogenesis, and steroids play a role in its elevated levels in those cells without known mechanism. Methods and Findings In this study, we investigated the molecular mechanism by which steroid hormones up-regulate p66Shc protein level. In steroid-treated human prostate and ovarian cancer cells, p66Shc protein levels were elevated, correlating with increased cell proliferation. These steroid effects on p66Shc protein and cell growth were competed out by the respective antagonist. Further, actinomycin D and cyclohexamide could only partially block the elevated p66Shc protein level by steroids. Treatment with proteasomal inhibitors, but not lysosomal protease inhibitor, resulted in elevated p66Shc protein levels, even higher than that by steroids. Using prostate cancer cells as a model, immunoprecipitation revealed that androgens and proteasomal inhibitors reduce the ubiquitinated p66Shc proteins. Conclusions The data collectively indicate that functional steroid receptors are required in steroid up-regulation of p66Shc protein levels in prostate and ovarian cancer cells, correlating with cell proliferation. In these steroid-treated cells, elevated p66Shc protein level is apparently in part due to inhibiting its ubiquitination. The results may lead to an impact on advanced cancer therapy via the regulation of p66Shc protein by up-regulating its ubiquitination pathway.
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Affiliation(s)
- Santosh Kumar
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Satyendra Kumar
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Mythilypriya Rajendran
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Syed Mahfuzul Alam
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Fen-Fen Lin
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Pi-Wan Cheng
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- Eppley Institute for Cancer Research, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Ming-Fong Lin
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- Eppley Institute for Cancer Research, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- * E-mail:
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Gasparrini F, Molfetta R, Santoni A, Paolini R. Cbl Family Proteins: Balancing FcεRI-Mediated Mast Cell and Basophil Activation. Int Arch Allergy Immunol 2011; 156:16-26. [DOI: 10.1159/000322236] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
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166
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Chou JLJ, Wu CHY, Tsai CY, Chang AYW, Chan SHH. Proteomic investigation of a neural substrate intimately related to brain death. Proteomics 2010; 11:239-48. [PMID: 21204251 DOI: 10.1002/pmic.201000438] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 10/15/2010] [Accepted: 10/18/2010] [Indexed: 01/18/2023]
Abstract
Our current understanding on brain death remains limited despite its clinical importance. This study evaluated whether the proteome expressed in the rat rostral ventrolateral medulla (RVLM), a neural substrate that our laboratory identified previously to be intimately related to brain death, is uniquely different from other brain areas, using the cerebral cortex, which is defunct under persistent vegetative state for comparison. We found that a group of antioxidant proteins, including members of the peroxiredoxin (Prx) family (Prx-1, Prx-2, Prx-5, Prx-6), thioredoxin and mitochondrial manganese superoxide dismutase, exhibited significantly higher protein and mRNA expression levels in RVLM when compared to cerebral cortex. Tissue oxygen, ATP contents and ATP synthase subunits α and β in RVLM were also significantly elevated. On the other hand, protein and mRNA levels of members of the ubiquitin-proteasome system, including proteasome subunit α type-1, ubiquitin, uniquitin-conjugating enzyme E2 N, ubiquitin carboxyl-terminal hydrolase isozyme L1 and L3, were comparable in both brain regions. We conclude that a significantly elevated level of antioxidant proteins and mRNA in RVLM is consistent with the exhibition of higher tissue oxygen tension and metabolic energy production in this neural substrate, which together constitute a safeguard mechanism against brain death.
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Affiliation(s)
- Jimmy Li-Jer Chou
- Center for Translational Research in Biomedical Sciences, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Kaohsiung County, Taiwan, Republic of China
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167
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Bedford L, Lowe J, Dick LR, Mayer RJ, Brownell JE. Ubiquitin-like protein conjugation and the ubiquitin-proteasome system as drug targets. Nat Rev Drug Discov 2010; 10:29-46. [PMID: 21151032 PMCID: PMC7097807 DOI: 10.1038/nrd3321] [Citation(s) in RCA: 433] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Ubiquitin is a highly conserved 76 amino-acid protein that covalently attaches to protein substrates targeted for degradation by the 26S proteasome. The coordinated effort of a series of enzymes, including an activating enzyme (E1), a conjugating enzyme (E2) and a ligase (E3), uses ATP to ultimately form an isopeptide bond between ubiquitin and a substrate. Another class of enzymes called deubiquitylating enzymes (DUBs) deconstruct these linkages and also have an essential role in ubiquitin function. In addition, ubiquitin-like proteins (UBLs), including NEDD8, SUMO and ISG15, share a characteristic three-dimensional fold with ubiquitin but have their own dedicated enzyme cascades and distinct (although sometimes overlapping) biological functions. The ubiquitin–proteasome system (UPS) and UBL conjugation pathways have important roles in various human diseases, including numerous types of cancer, cardiovascular disease, viral diseases and neurodegenerative disorders. The proteasome inhibitor bortezomib (Velcade; Millennium Pharmaceuticals) is the first clinically validated drug to target the UPS and is approved for the treatment of multiple myeloma. This suggests that other diseases may conceivably be targeted by modulating components of the UPS and UBL conjugation pathways using small-molecule inhibitors. A significant hurdle to identifying drug-like inhibitors of enzyme targets within the UPS and UBL conjugation pathways is the limited understanding of the molecular mechanisms and biological consequences of UBL conjugation. Here, we provide an overview of the enzyme classes in the UPS and UBL pathways that are potential therapeutic targets, and highlight considerations that are important for drug discovery. We also discuss the progress in the development of small-molecule inhibitors, and review developments in understanding of the role of the components of the UPS and the UBL pathways in disease and their potential for therapeutic intervention.
The ubiquitin–proteasome system (UPS) and ubiquitin-like protein (UBL) conjugation pathways are integral to cellular protein homeostasis, and their functional importance in various diseases, including cancer, cardiovascular disease and neurodegenerative disorders, is now beginning to emerge. Brownell and colleagues review developments in understanding of the role of the components of the UPS and the UBL pathways in disease and their potential for therapeutic intervention. The ubiquitin–proteasome system (UPS) and ubiquitin-like protein (UBL) conjugation pathways are integral to cellular protein homeostasis. The growing recognition of the fundamental importance of these pathways to normal cell function and in disease has prompted an in-depth search for small-molecule inhibitors that selectively block the function of these pathways. However, our limited understanding of the molecular mechanisms and biological consequences of UBL conjugation is a significant hurdle to identifying drug-like inhibitors of enzyme targets within these pathways. Here, we highlight recent advances in understanding the role of some of these enzymes and how these new insights may be the key to developing novel therapeutics for diseases including immuno-inflammatory disorders, cancer, infectious diseases, cardiovascular disease and neurodegenerative disorders.
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Affiliation(s)
- Lynn Bedford
- School of Biomedical Sciences, University of Nottingham, Nottingham, UK.
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168
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Abstract
Saccharomyces cerevisiae cells lacking the Slx5-Slx8 SUMO-targeted Ub ligase display increased levels of sumoylated and polysumoylated proteins, and they are inviable in the absence of the Sgs1 DNA helicase. One explanation for this inviability is that one or more sumoylated proteins accumulate to toxic levels in sgs1Δ slx5Δ cells. To address this possibility, we isolated a second-site suppressor of sgs1Δ slx5Δ synthetic lethality and identified it as an allele of the ULP2 SUMO isopeptidase. The suppressor, ulp2-D623H, behaved like the ulp2Δ allele in its sensitivity to heat, DNA replication stress, and DNA damage. Surprisingly, deletion of ULP2, which is known to promote the accumulation of poly-SUMO chains, suppressed sgs1Δ slx5Δ synthetic lethality and the slx5Δ sporulation defect. Further, ulp2Δ's growth sensitivities were found to be suppressed in ulp2Δ slx5Δ double mutants. This mutual suppression indicates that SLX5-SLX8 and ULP2 interact antagonistically. However, the suppressed strain sgs1Δ slx5Δ ulp2-D623H displayed even higher levels of sumoylated proteins than the corresponding double mutants. Thus, sgs1Δ slx5Δ synthetic lethality cannot be due simply to high levels of bulk sumoylated proteins. We speculate that the loss of ULP2 suppresses the toxicity of the sumoylated proteins that accumulate in slx5Δ-slx8Δ cells by permitting the extension of poly-SUMO chains on specific target proteins. This additional modification might attenuate the activity of the target proteins or channel them into alternative pathways for proteolytic degradation. In support of this latter possibility we find that the WSS1 isopeptidase is required for suppression by ulp2Δ.
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169
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Abstract
Angelman syndrome is characterized by severe developmental delay, speech impairment, gait ataxia and/or tremulousness of the limbs, and a unique behavioral phenotype that includes happy demeanor and excessive laughter. Microcephaly and seizures are common. Developmental delays are first noted at 3 to 6 months age, but the unique clinical features of the syndrome do not become manifest until after age 1 year. Management includes treatment of gastrointestinal symptoms, use of antiepileptic drugs for seizures, and provision of physical, occupational, and speech therapy with an emphasis on nonverbal methods of communication. The diagnosis rests on a combination of clinical criteria and molecular and/or cytogenetic testing. Analysis of parent-specific DNA methylation imprints in the 15q11.2-q13 chromosome region detects approximately 78% of individuals with lack of maternal contribution. Less than 1% of individuals have a visible chromosome rearrangement. UBE3A sequence analysis detects mutations in an additional 11% of individuals. The remaining 10% of individuals with classic phenotypic features of Angelman syndrome have a presently unidentified genetic mechanism and thus are not amenable to diagnostic testing. The risk to sibs of a proband depends on the genetic mechanism of the loss of the maternally contributed Angelman syndrome/Prader-Willi syndrome region: typically <1% for probands with a deletion or uniparental disomy; as high as 50% for probands with an imprinting defect or a mutation of UBE3A. Members of the mother's extended family are also at increased risk when an imprinting defect or a UBE3A mutation is present. Chromosome rearrangements may be inherited or de novo. Prenatal testing is possible for certain genetic mechanisms.
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170
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Structure characterization of the 26S proteasome. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2010; 1809:67-79. [PMID: 20800708 DOI: 10.1016/j.bbagrm.2010.08.008] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2009] [Revised: 08/17/2010] [Accepted: 08/19/2010] [Indexed: 01/27/2023]
Abstract
In all eukaryotic cells, 26S proteasome plays an essential role in the process of ATP-dependent protein degradation. In this review, we focus on structure characterization of the 26S proteasome. Although the progress towards a high-resolution structure of the 26S proteasome has been slow, the recently solved structures of various proteasomal subcomplexes have greatly enhanced our understanding of this large machinery. In addition to having an ATP-dependent proteolytic function, the 26S proteasome is also involved in many non-proteolytic cellular activities, which are often mediated by subunits in its 19S regulatory complex. Thus, we include a detailed discussion of the structures of 19S subunits, including proteasomal ATPases, ubiquitin receptors, deubiquitinating enzymes and subunits that contain PCI domain. This article is part of a Special Issue entitled The 26S Proteasome: When degradation is just not enough!
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171
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Henry L, Lavabre-Bertrand T, Douche T, Uttenweiler-Joseph S, Fabbro-Peray P, Monsarrat B, Martinez J, Meunier L, Stoebner PE. Diagnostic value and prognostic significance of plasmatic proteasome level in patients with melanoma. Exp Dermatol 2010; 19:1054-9. [PMID: 20707810 DOI: 10.1111/j.1600-0625.2010.01151.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Plasmatic proteasome (p-proteasome) also called circulating proteasome has recently been described as a tumor marker. We investigated the diagnostic and prognostic accuracies of p-proteasome levels in a melanoma population classified according to the American Joint Committee on Cancer staging system. Using an ELISA test, we measured p-proteasome levels in 90 patients and 40 controls between March 2003 and March 2008. The subunit composition of p-proteasomes was determined in metastatic melanoma by proteomic analysis. The mean p-proteasome levels were correlated with stages (P < 0.0001; r(S) = 0.664). They were significantly higher in patients with stage IV and stage III with lymph node metastasis (9187 ± 1294 and 5091 ± 454 ng/ml, respectively) compared to controls (2535 ± 187 ng/ml; P < 0.001), to stage I/II (2864 ± 166 ng/ml; P < 0.001) and to stage III after curative lymphadenectomy (2859 ± 271 ng/ml; P < 0.001). The diagnostic accuracy of p-proteasome was evaluated by receiver operating characteristic analysis. With a cut-off of 4300 ng/ml, diagnostic specificity and sensitivity of p-proteasome for regional or visceral metastases were respectively 96.3% and 72.2%. In univariate analysis, high p-proteasome levels (>4300 ng/ml) were significantly correlated with an increased risk of progression [hazard ratio (HR) = 7.34; 95% CI 3.54-15.21, P < 0.0001] and a risk of death (HR = 5.92; 95% CI 2.84-12.33, P < 0.0001). In multivariate analysis, high p-proteasome levels were correlated with a poorer clinical outcome in the subgroup analysis limited to patients with disease stages I, II and III. Proteomic analysis confirmed the presence of all proteasome and immunoproteasome subunits. Taken together, these results indicate that p-proteasomes are a new marker for metastatic dissemination in patients with melanoma.
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Affiliation(s)
- Laurent Henry
- Laboratoire d'Histologie-Embryologie-Cytogénétique, Université Montpellier 1, Faculté de Médecine Montpellier-Nîmes, CHU de Nîmes, Nîmes, France
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172
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Ron I, Rapaport D, Horowitz M. Interaction between parkin and mutant glucocerebrosidase variants: a possible link between Parkinson disease and Gaucher disease. Hum Mol Genet 2010; 19:3771-81. [PMID: 20643691 DOI: 10.1093/hmg/ddq292] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Gaucher disease (GD), a sphingolipidosis characterized by impaired activity of the lysosomal enzyme glucocerebrosidase (GCase), results from mutations in the GCase-encoding gene, GBA. We have shown that mutant GCase variants present variable degrees of endoplasmic reticulum (ER) retention and undergo ER-associated degradation (ERAD) in the proteasome. Furthermore, the degree of ERAD of mutant GCase variants correlates with and is one of the factors that determine GD severity. An association between GD and Parkinson disease (PD) has been demonstrated by the concurrence of PD in GD patients and the identification of GCase mutations in probands with sporadic PD. One of the genes involved in PD is PARK2, encoding the E3 ubiquitin ligase parkin. Parkin functions in the ERAD of misfolded ER proteins, and it is upregulated by unfolded protein response. Loss of parkin function leads to the accumulation of its substrates, which is deleterious to dopaminergic neurons in PD. We, therefore, tested the possibility that the association between GD and PD reflects the fact that parkin acts as an E3 ligase of mutant GCase variants. Our results showed that mutant GCase variants associate with parkin. Normal parkin, but not its RING finger mutants, affects the stability of mutant GCase variants. Parkin also promotes the accumulation of mutant GCase in aggresome-like structures and is involved in K48-mediated polyubiquitination of GCase mutants, indicating its function as its E3 ligase. We suggest that involvement of parkin in the degradation of mutant GCase explains the concurrence of GD and PD.
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Affiliation(s)
- Idit Ron
- Department of Cell Research and Immunology, Tel Aviv University, Ramat Aviv 69978, Israel
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173
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The role of the ubiquitin proteasome pathway in keratin intermediate filament protein degradation. Ann Am Thorac Soc 2010; 7:71-6. [PMID: 20160151 DOI: 10.1513/pats.200908-089js] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Lung injury, whether caused by hypoxic or mechanical stresses, elicits a variety of responses at the cellular level. Alveolar epithelial cells respond and adapt to such injurious stimuli by reorganizing the cellular cytoskeleton, mainly accomplished through modification of the intermediate filament (IF) network. The structural and mechanical integrity in epithelial cells is maintained through this adaptive reorganization response. Keratin, the predominant IF expressed in epithelial cells, displays highly dynamic properties in response to injury, sometimes in the form of degradation of the keratin IF network. Post-translational modification, such as phosphorylation, targets keratin proteins for degradation in these circumstances. As with other structural and regulatory proteins, turnover of keratin is regulated by the ubiquitin (Ub)-proteasome pathway. The degradation process begins with activation of Ub by the Ub-activating enzyme (E1), followed by the exchange of Ub to the Ub-conjugating enzyme (E2). E2 shuttles the Ub molecule to the substrate-specific Ub ligase (E3), which then delivers the Ub to the substrate protein, thereby targeting it for degradation. In some cases of injury and IF-related disease, aggresomes form in epithelial cells. The mechanisms that regulate aggresome formation are currently unknown, although proteasome overload may play a role. Therefore, a more complete understanding of keratin degradation--causes, mechanisms, and consequences--will allow for a greater understanding of epithelial cell biology and lung pathology alike.
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174
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Jagannath S, Dimopoulos MA, Lonial S. Combined proteasome and histone deacetylase inhibition: A promising synergy for patients with relapsed/refractory multiple myeloma. Leuk Res 2010; 34:1111-8. [PMID: 20472288 DOI: 10.1016/j.leukres.2010.04.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Revised: 04/01/2010] [Accepted: 04/04/2010] [Indexed: 11/27/2022]
Abstract
Multiple myeloma (MM) is an incurable disease characterized by the accumulation of malignant plasma cells in the bone marrow. Recently, an improved understanding of the biology of the disease has led to the development of targeted agents such as the proteasome inhibitor bortezomib and the immunomodulatory agents thalidomide and lenalidomide; however, MM remains incurable. The combination of bortezomib and an HDAC inhibitor synergistically induces MM cell apoptosis and may be of value in the treatment of patients with relapsed/refractory MM. This review examines the potential of combined proteasome and HDAC inhibition in the treatment of relapsed/refractory MM.
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Affiliation(s)
- Sundar Jagannath
- St Vincent's Catholic Medical Center, 325 W. 15th Street, New York, NY 10011-8202, USA.
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175
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Yanaba K, Yoshizaki A, Muroi E, Hara T, Ogawa F, Shimizu K, Sato S. The proteasome inhibitor bortezomib inhibits T cell-dependent inflammatory responses. J Leukoc Biol 2010; 88:117-22. [DOI: 10.1189/jlb.1009666] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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176
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Piette MHA, Pieters SEP, De Letter EA. Evaluation of the agonal stress: can immunohistochemical detection of ubiquitin in the locus coeruleus be useful? Int J Legal Med 2010; 125:333-40. [PMID: 20396898 DOI: 10.1007/s00414-010-0434-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Accepted: 02/19/2010] [Indexed: 11/25/2022]
Abstract
The determination of the survival time after a crime as well as the concomitant physical and mental load of the victim is an important task for the forensic pathologist. The heat shock protein, ubiquitin, exerts an essential role in the cellular response to stress. We aimed to investigate the usefulness of the ubiquitin expression in the locus coeruleus as a marker for the evaluation of agonal stress. Is the amount of ubiquitin in this brain locus an indication of the length and/or intensity of the agonal period following various causes of death? The immunohistochemical (IHC) expression of ubiquitin is examined in formalin-fixed, paraffin-embedded slides of the human locus coeruleus (n = 48). The evaluation of the IHC staining is blindly performed, prior to the study of the medico-legal files. According to the length of agony, a division into subgroups is made. Three possible IHC staining patterns are observed: a staining of the neuronal nucleus or the cytoplasm or both. In addition, the number of neurons with ubiquitin expression per μm(2) is calculated in each locus coeruleus. Significant differences in the number of ubiquitin-immunoreactive neurons are noticed with respect to the length of the agony: A higher density of positive neurons is seen in case of a pronounced and extended death struggle.
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Affiliation(s)
- Michel H A Piette
- Department of Forensic Medicine, Forensic Institute Ghent University, J. Kluyskensstraat 29, 9000, Ghent, Belgium.
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177
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Reece DE, Sullivan D, Lonial S, Mohrbacher AF, Chatta G, Shustik C, Burris H, Venkatakrishnan K, Neuwirth R, Riordan WJ, Karol M, von Moltke LL, Acharya M, Zannikos P, Keith Stewart A. Pharmacokinetic and pharmacodynamic study of two doses of bortezomib in patients with relapsed multiple myeloma. Cancer Chemother Pharmacol 2010; 67:57-67. [PMID: 20306195 DOI: 10.1007/s00280-010-1283-3] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2009] [Accepted: 02/09/2010] [Indexed: 11/27/2022]
Abstract
PURPOSE Characterize bortezomib pharmacokinetics/pharmacodynamics in relapsed myeloma patients after single and repeat intravenous administration at two doses. METHODS Forty-two patients were randomized to receive bortezomib 1.0 or 1.3 mg/m(2), days 1, 4, 8, 11, for up to eight 21-day treatment cycles (n = 21, each dose group). Serial blood samples for pharmacokinetic/pharmacodynamic analysis were taken on days 1 and 11, cycles 1 and 3. Observational efficacy and safety data were collected. RESULTS Twelve patients in each dose group were evaluable for pharmacokinetics/pharmacodynamics. Plasma clearance decreased with repeat dosing (102-112 L/h for first dose; 15-32 L/h following repeat dosing), with associated increases in systemic exposure and terminal half-life. Systemic exposures of bortezomib were similar between dose groups considering the relatively narrow dose range and the observed pharmacokinetic variability, although there was no readily apparent deviation from dose-proportionality. Blood 20S proteasome inhibition profiles were similar between groups with mean maximum inhibition ranging from 70 to 84% and decreasing toward baseline over the dosing interval. Response rate (all 42 patients) was 50%, including 7% complete responses. The safety profile was consistent with the predictable and manageable profile previously established; data suggested milder toxicity in the 1.0 mg/m(2) group. CONCLUSIONS Bortezomib pharmacokinetics change with repeat dose administration, characterized by a reduction in plasma clearance and associated increase in systemic exposure. Bortezomib is pharmacodynamically active and tolerable at 1.0 and 1.3 mg/m(2) doses, with recovery toward baseline blood proteasome activity over the dosing interval following repeat dose administration, supporting the current clinical dosing regimen.
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Affiliation(s)
- Donna E Reece
- Department of Medical Oncology and Hematology, Princess Margaret Hospital, 610 University Avenue, Toronto, Ontario M5G 2M9, Canada.
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178
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Abstract
One of the more rapidly expanding fields in cell signalling nowadays is the characterization of proteins conjugated to Ub (ubiquitin) or Ub-like peptides, such as SUMO (small Ub-related modifier). The reversible covalent attachment of these small peptides remodels the target protein, providing new protein-protein interaction interfaces, which can be dynamically regulated given a set of enzymes for conjugation and deconjugation. First, ubiquitination was thought to be merely relegated to the control of protein turnover and degradation, whereas the attachment of SUMO was involved in the regulation of protein activity and function. However, the boundaries between the protein fates related to these tag molecules are becoming more and more fuzzy, as either the differences between mono-, multi- and poly-modifications or the lysine residue used for growth of the poly-chains is being dissected. The Ub and SUMO pathways are no longer separated, and many examples of this cross-talk are found in the literature, involving different cellular processes ranging from DNA repair and genome stability, to the regulation of protein subcellular localization or enzyme activity. Here, we review several cases in which SUMOylation and ubiquitination intersect, showing also that the same protein can be conjugated to SUMO and Ub for antagonistic, synergistic or multiple outcomes, illustrating the intricacy of the cellular signalling networks. Ub and SUMO have met and are now applying for new regulatory roles in the cell.
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179
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Campbell RA, Sanchez E, Steinberg J, Shalitin D, Li ZW, Chen H, Berenson JR. Vorinostat enhances the antimyeloma effects of melphalan and bortezomib. Eur J Haematol 2010; 84:201-11. [DOI: 10.1111/j.1600-0609.2009.01384.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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180
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Dowd WW, Harris BN, Cech JJ, Kültz D. Proteomic and physiological responses of leopard sharks (Triakis semifasciata) to salinity change. J Exp Biol 2010; 213:210-24. [DOI: 10.1242/jeb.031781] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
SUMMARY
Partially euryhaline elasmobranchs may tolerate physiologically challenging, variable salinity conditions in estuaries as a trade-off to reduce predation risk or to gain access to abundant food resources. To further understand these trade-offs and to evaluate the underlying mechanisms, we examined the responses of juvenile leopard sharks to salinity changes using a suite of measurements at multiple organizational levels: gill and rectal gland proteomes (using 2-D gel electrophoresis and tandem mass spectrometry), tissue biochemistry (Na+/K+-ATPase, caspase 3/7 and chymotrypsin-like proteasome activities), organismal physiology (hematology, plasma composition, muscle moisture) and individual behavior. Our proteomics results reveal coordinated molecular responses to low salinity – several of which are common to both rectal gland and gill – including changes in amino acid and inositol (i.e. osmolyte) metabolism, energy metabolism and proteins related to transcription, translation and protein degradation. Overall, leopard sharks employ a strategy of maintaining plasma urea, ion concentrations and Na+/K+-ATPase activities in the short-term, possibly because they rarely spend extended periods in low salinity conditions in the wild, but the sharks osmoconform to the surrounding conditions by 3 weeks. We found no evidence of apoptosis at the time points tested, while both tissues exhibited proteomic changes related to the cytoskeleton, suggesting that leopard sharks remodel existing osmoregulatory epithelial cells and activate physiological acclimatory responses to solve the problems posed by low salinity exposure. The behavioral measurements reveal increased activity in the lowest salinity in the short-term, while activity decreased in the lowest salinity in the long-term. Our data suggest that physiological/behavioral trade-offs are involved in using estuarine habitats, and pathway modeling implicates tumor necrosis factor α (TNFα) as a key node of the elasmobranch hyposmotic response network.
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Affiliation(s)
- W. W. Dowd
- Physiological Genomics Group, Department of Animal Science, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, USA
- Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, USA
| | - B. N. Harris
- Department of Biology, 3386 Spieth Hall, University of California, Riverside, CA 92521, USA
| | - J. J. Cech
- Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, USA
| | - D. Kültz
- Physiological Genomics Group, Department of Animal Science, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, USA
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181
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Abstract
The introduction of novel agents, such as thalidomide, bortezomib, and lenalidomide, has altered the landscape of therapeutic options for multiple myeloma by offering new mechanisms for targeting this disease. Combinations of these agents, with each other and/or traditional chemotherapeutics, have vastly increased the treatment options for patients both frontline, and at relapse, providing higher response rates, and importantly, increasing median overall survival. In this review, we will discuss the use of these novel agents and their combinations in patients with relapsed and/or refractory multiple myeloma.
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182
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Peschiaroli A, Skaar JR, Pagano M, Melino G. The ubiquitin-specific protease USP47 is a novel beta-TRCP interactor regulating cell survival. Oncogene 2009; 29:1384-93. [PMID: 19966869 DOI: 10.1038/onc.2009.430] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Ubiquitin-specific proteases (USPs) are a subclass of cysteine proteases that catalyze the removal of ubiquitin (either monomeric or chains) from substrates, thus counteracting the activity of E3 ubiquitin ligases. Although the importance of USPs in a multitude of processes, from hereditary cancer to neurodegeneration, is well established, our knowledge on their mode of regulation, substrate specificity and biological function is quite limited. In this study we identify USP47 as a novel interactor of the E3 ubiquitin ligase, Skp1/Cul1/F-box protein beta-transducin repeat-containing protein (SCF(beta-Trcp)). We found that both beta-Trcp1 and beta-Trcp2 bind specifically to USP47, and point mutations in the beta-Trcp WD-repeat region completely abolished USP47 binding, indicating an E3-substrate-type interaction. However, unlike canonical beta-Trcp substrates, USP47 protein levels were neither affected by silencing of beta-Trcp nor modulated in a variety of processes, such as cell-cycle progression, DNA damage checkpoint responses or tumor necrosis factor (TNF) pathway activation. Notably, genetic or siRNA-mediated depletion of USP47 induced accumulation of Cdc25A, decreased cell survival and augmented the cytotoxic effects of anticancer drugs. In conclusion, we showed that USP47, a novel beta-Trcp interactor, regulates cell growth and survival, potentially providing a novel target for anticancer therapies.
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Affiliation(s)
- A Peschiaroli
- IDI IRCCS Biochemistry Laboratory, Department of Experimental Medicine and Biochemical Sciences, University of Rome Tor Vergata, Rome, Italy
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183
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Amschler K, Schön MP, Pletz N, Wallbrecht K, Erpenbeck L, Schön M. NF-kappaB inhibition through proteasome inhibition or IKKbeta blockade increases the susceptibility of melanoma cells to cytostatic treatment through distinct pathways. J Invest Dermatol 2009; 130:1073-86. [PMID: 19940859 DOI: 10.1038/jid.2009.365] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Metastasized melanoma is almost universally resistant to chemotherapy. Given that constitutive or drug-induced upregulation of NF-kappaB activity is associated with this chemoresistance, NF-kappaB inhibition may increase the susceptibility to antitumoral therapy. On the cellular level, two principles of NF-kappaB inhibition, proteasome inhibition by bortezomib and IkappaB kinase-beta (IKKbeta) inhibition by the kinase inhibitor of NF-kappaB-1 (KINK-1), significantly increased the antitumoral efficacy of camptothecin. When combined with camptothecin, either of the two NF-kappaB-inhibiting principles synergistically influenced progression-related in vitro functions, including cell growth, apoptosis, and invasion through an artificial basement membrane. In addition, when C57BL/6 mice were intravenously injected with B16F10 melanoma cells, the combination of cytostatic treatment with either of the NF-kappaB-inhibiting compounds revealed significantly reduced pulmonary metastasis compared to either treatment alone. However, on the molecular level, nuclear translocation of p65, cell cycle analysis, and expression of NF-kappaB-dependent gene products disclosed distinctly different molecular mechanisms, resulting in the same functional effect. That proteasome inhibition and IKKbeta inhibition affect distinct molecular pathways downstream of NF-kappaB, both leading to increased chemosensitivity, is previously unreported. Thus, it is conceivable that switching the two principles of NF-kappaB inhibition, once resistance to one of the agents occurs, will improve future treatment regimens.
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Affiliation(s)
- Katharina Amschler
- Department of Dermatology and Venereology, Georg August University, Göttingen, Germany
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184
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Seliger B, Handke D, Schabel E, Bukur J, Lichtenfels R, Dammann R. Epigenetic control of the ubiquitin carboxyl terminal hydrolase 1 in renal cell carcinoma. J Transl Med 2009; 7:90. [PMID: 19857250 PMCID: PMC2775027 DOI: 10.1186/1479-5876-7-90] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Accepted: 10/26/2009] [Indexed: 12/12/2022] Open
Abstract
Background The ubiquitin carboxyl-terminal hydrolase 1 (UCHL1) gene involved in the regulation of cellular ubiquitin levels plays an important role in different cellular processes including cell growth and differentiation. Aberrant expression of UCHL1 has been found in a number of human solid tumors including renal cell carcinoma (RCC). In RCC, UCHL1 overexpression is associated with tumor progression and an altered von Hippel Lindau gene expression. Methods To determine the underlying mechanisms for the heterogeneous UCHL1 expression pattern in RCC the UCHL1 promoter DNA methylation status was determined in 17 RCC cell lines as well as in 32 RCC lesions and corresponding tumor adjacent kidney epithelium using combined bisulfite restriction analysis as well as bisulfite DNA sequencing. Results UCHL1 expression was found in all 32 tumor adjacent kidney epithelium samples. However, the lack of or reduced UCHL1 mRNA and/or protein expression was detected in 13/32 RCC biopsies and 7/17 RCC cell lines and due to either a total or partial methylation of the UCHL1 promoter DNA. Upon 2'-deoxy-5-azacytidine treatment an induction of UCHL1 mRNA and protein expression was found in 9/17 RCC cell lines, which was linked to the demethylation degree of the UCHL1 promoter DNA. Conclusion Promoter hypermethylation represents a mechanism for the silencing of the UCHL1 gene expression in RCC and supports the concept of an epigenetic control for the expression of UCHL1 during disease progression.
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Affiliation(s)
- Barbara Seliger
- Martin Luther University Halle-Wittenberg, Institute of Medical Immunology, Halle, Germany.
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185
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Ramaswamy B, Bekaii-Saab T, Schaaf LJ, Lesinski GB, Lucas DM, Young DC, Ruppert AS, Byrd JC, Culler K, Wilkins D, Wright JJ, Grever MR, Shapiro CL. A dose-finding and pharmacodynamic study of bortezomib in combination with weekly paclitaxel in patients with advanced solid tumors. Cancer Chemother Pharmacol 2009; 66:151-8. [PMID: 19774377 DOI: 10.1007/s00280-009-1145-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Accepted: 09/12/2009] [Indexed: 01/04/2023]
Abstract
PURPOSE A phase I study to determine the maximum tolerated dose (MTD) of bortezomib (B) when combined with weekly paclitaxel in patients with advanced solid tumors. PATIENTS AND METHODS Eligible patients received escalating doses of intravenous (IV) bortezomib (0.6-2 mg/m(2)) on days 2 and 9 and IV paclitaxel at 100 mg/m(2) on days 1 and 8 of a 21-day cycle. Dose escalation was based on two end-points: not exceeding 80% 20S-proteasome inhibition (20-S PI) and the development of dose-limiting toxicity defined as grade 3 or greater non-hematologic or grade 4 hematologic toxicities. RESULTS Forty-five patients with advanced solid tumors and a median of 3 prior chemotherapy regimens (range 0-9), received 318 doses (median 5, range 1-34) of bortezomib and paclitaxel. Dose-related inhibition of 20-S PI was observed with a maximum inhibition of 70-80% at the MTD of 1.8 mg/m(2) of bortezomib. At the MTD (N = 9) the following toxicities were observed: grade 4 neutropenia without fever (n = 2) and cerebrovascular ischemia (n = 1); grade 3 neutropenia (n = 3), diarrhea (n = 2), nausea (n = 1), and fatigue (n = 1); grade 2 fatigue (n = 5), diarrhea (n = 4), and dyspnea (n = 2). There was one partial response in a patient with an eccrine porocarcinoma. Stabilization of disease was observed in 7 (16%) patients, 3 of whom had advanced pancreatic cancer. CONCLUSION Sequential paclitaxel and bortezomib in previously treated patients with advanced solid tumors resulted in acceptable toxicity and no evidence of interaction. The recommended phase II dose of bortezomib in combination with weekly paclitaxel was 1.8 mg/m(2).
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Affiliation(s)
- Bhuvaneswari Ramaswamy
- The Ohio State University, B401, Starling Loving Hall, 320 W 10th av, Columbus, OH 43210, USA.
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186
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Abstract
Parkinson's disease (PD) is a progressive neurodegenerative disease and is characterized pathologically by selective loss of nigrostriatal dopaminergic neurons and the formation of Lewy bodies. Although in the majority of cases the cause of PD is unknown, mitochondrial dysfunction, environmental toxins, oxidative stress, and abnormal protein accumulation may all be involved in disease pathogenesis. The discovery of genes causing rare familial forms of PD (including alpha-synuclein, parkin, DJ-1, PINK1, and LRRK2) has shed light on our understanding of the molecular mechanisms of the development of the disease. Further studies from transgenic or toxin-induced experimental models have also provided insights into the etiology of human disease. Recently, accumulating evidence has suggested that mitochondrial dysfunction is one of the key players in molecular cell death pathways of PD. In this review, we provide an overview of the role of mitochondria in the pathogenesis of both sporadic and familial forms of PD. We also discuss the links between different pathways and highlight novel therapeutic opportunities which target mitochondria.
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Affiliation(s)
- Zhi Yao
- UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, London, United Kingdom
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187
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Song KY, Choi HS, Hwang CK, Kim CS, Law PY, Wei LN, Loh HH. Differential use of an in-frame translation initiation codon regulates human mu opioid receptor (OPRM1). Cell Mol Life Sci 2009; 66:2933-42. [PMID: 19609488 PMCID: PMC11115551 DOI: 10.1007/s00018-009-0082-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2009] [Revised: 06/05/2009] [Accepted: 06/19/2009] [Indexed: 11/26/2022]
Abstract
The pharmacological effects of morphine and morphine-like drugs are mediated primarily through the micro opioid receptor. Here we show that differential use of an in-frame translational start codon in the 5'-untranslated region of the OPRM1 generates different translational products in vivo and in vitro. The 5'-end of the OPRM1 gene is necessary for initiating the alternate form and for subsequent degradation of the protein. Initiation of OPRM1 at the upstream site decreases the initiation at the main AUG site. However, alternative initiation of the long form of OPRM1 produces a protein with a short half-life, resulting from degradation mediated by the ubiquitin-proteasome pathway. Reporter and degradation assays showed that mutations of this long form at the second and third lysines reduce ubiquitin-dependent proteasome degradation, stabilizing the protein. The data suggest that MOP expression is controlled in part by initiation of the long form of MOP at the alternate site.
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Affiliation(s)
- Kyu Young Song
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, MN 55455, USA.
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188
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Abdelmegeed MA, Moon KH, Chen C, Gonzalez FJ, Song BJ. Role of cytochrome P450 2E1 in protein nitration and ubiquitin-mediated degradation during acetaminophen toxicity. Biochem Pharmacol 2009; 79:57-66. [PMID: 19660437 DOI: 10.1016/j.bcp.2009.07.016] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2009] [Revised: 07/28/2009] [Accepted: 07/28/2009] [Indexed: 12/17/2022]
Abstract
It is well established that following a toxic dose of acetaminophen (APAP), nitrotyrosine protein adducts (3-NT), a hallmark of peroxynitrite production, were colocalized with necrotic hepatic centrilobular regions where cytochrome P450 2E1 (CYP2E1) is highly expressed, suggesting that 3-NT formation may be essential in APAP-mediated toxicity. This study was aimed at investigating the relationship between CYP2E1 and nitration (3-NT formation) followed by ubiquitin-mediated degradation of proteins in wild-type and Cyp2e1-null mice exposed to APAP (200 and 400mg/kg) for 4 and 24h. Markedly increased centrilobular liver necrosis and 3-NT formation were only observed in APAP-exposed wild-type mice in a dose- and time-dependent manner, confirming an important role for CYP2E1 in APAP biotransformation and toxicity. However, the pattern of 3-NT protein adducts, not accompanied by concurrent activation of nitric oxide synthase (NOS), was similar to that of protein ubiquitination. Immunoblot analysis further revealed that immunoprecipitated nitrated proteins were ubiquitinated in APAP-exposed wild-type mice, confirming the fact that nitrated proteins are more susceptible than the native proteins for ubiquitin-dependent degradation, resulting in shorter half-lives. For instance, cytosolic superoxide dismutase (SOD1) levels were clearly decreased and immunoprecipitated SOD1 was nitrated and ubiquitinated, likely leading to its accelerated degradation in APAP-exposed wild-type mice. These data suggest that CYP2E1 appears to play a key role in 3-NT formation, protein degradation, and liver damage, which is independent of NOS, and that decreased levels of many proteins in the wild-type mice (compared with Cyp2e1-null mice) likely contribute to APAP-related toxicity.
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Affiliation(s)
- Mohamed A Abdelmegeed
- Laboratory of Membrane Biochemistry and Biophysics, National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, USA
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189
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Ang E, Pavlos NJ, Rea SL, Qi M, Chai T, Walsh JP, Ratajczak T, Zheng MH, Xu J. Proteasome inhibitors impair RANKL-induced NF-κB activity in osteoclast-like cells via disruption of p62, TRAF6, CYLD, and IκBα signaling cascades. J Cell Physiol 2009; 220:450-9. [DOI: 10.1002/jcp.21787] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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190
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Chanvorachote P, Pongrakhananon V, Wannachaiyasit S, Luanpitpong S, Rojanasakul Y, Nimmannit U. Curcumin Sensitizes Lung Cancer Cells to Cisplatin-Induced Apoptosis Through Superoxide Anion-Mediated Bcl-2 Degradation. Cancer Invest 2009; 27:624-35. [DOI: 10.1080/07357900802653472] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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191
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Su H, Fan W, Coskun PE, Vesa J, Gold JA, Jiang YH, Potluri P, Procaccio V, Acab A, Weiss JH, Wallace DC, Kimonis VE. Mitochondrial dysfunction in CA1 hippocampal neurons of the UBE3A deficient mouse model for Angelman syndrome. Neurosci Lett 2009; 487:129-33. [PMID: 19563863 DOI: 10.1016/j.neulet.2009.06.079] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2009] [Revised: 06/19/2009] [Accepted: 06/20/2009] [Indexed: 11/26/2022]
Abstract
Angelman syndrome (AS) is a severe neurological disorder caused by a deficiency of ubiquitin protein ligase E3A (UBE3A), but the pathophysiology of the disease remains unknown. We now report that in the brains of AS mice in which the maternal UBE3A allele is mutated (m-) and the paternal allele is potentially inactivated by imprinting (p+) (UBE3A m-\p+), the mitochondria are abnormal and exhibit a partial oxidative phosphorylation (OXPHOS) defect. Electron microscopy of the hippocampal region of the UBE3A m-\p+ mice (n=6) reveals small, dense mitochondria with altered cristae, relative to wild-type littermates (n=6) and reduced synaptic vesicle density. The specific activity of OXPHOS complex III is reduced in whole brain mitochondria in UBE3A m-\p+ (n=5) mice versus wild-type littermates (n=5). Therefore, mitochondrial dysfunction may contribute to the pathophysiology of Angelman syndrome.
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Affiliation(s)
- Hailing Su
- Department of Pediatrics, Division of Genetics and Metabolism, University of California, Irvine, CA 92697, USA
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192
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Nirmala X, Zimowska GJ, Handler AM. Characterization of the proteasomebeta2 subunit gene and its mutant allele in the tephritid fruit fly pest, Anastrepha suspensa. INSECT MOLECULAR BIOLOGY 2009; 18:333-340. [PMID: 19523065 DOI: 10.1111/j.1365-2583.2009.00875.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In Drosophila melanogaster the beta2 proteasome subunit gene, Prosbeta2, was first identified as a dominant temperature sensitive mutant, DTS-7, that causes pupal lethality at 29 degrees C but allows survival to adulthood at 25 degrees C. To explore the use of proteasome mutations for a conditional lethal system in insect pests, we identified and isolated the beta2 subunit gene of the 20S proteasome from the Caribbean fruit fly, Anastrepha suspensa. The caribfly ortholog AsProsbeta2 was isolated from pupal cDNA by 5' and 3' RACE. The AsProsbeta2 protein has high amino acid sequence similarity to predicted insect Prosbeta2 subunits and homologs from yeast and mammals, and it contains the well conserved amino acids that confer catalytic activity and substrate specificity. AsProsbeta2 is a single copy gene and its RNA accumulates throughout all developmental stages of the caribfly. For functional studies a point mutation, analogous to the Prosbeta2(1) mutation in D. melanogaster, was introduced into AsProsbeta2 to create an aberrant protein with a Gly170Arg substitution. Consistent with the DTS-7 mutation, transgenic insects carrying the mutant allele undergo normal metamorphosis at the permissive temperature (25 degrees C) but at the non-permissive temperature (29 degrees C) they exhibit effective pupal lethality. This is the first report of a functional characterization of a Prosbeta2 cognate based on the creation of a dominant temperature-sensitive mutation. This type of temperature-dependent lethality could be used for biological control, where transgenic insects are reared to adulthood at 25 degrees C or lower and then released into the field where ambient temperatures averaging 29 degrees C or greater cause lethality in their progeny.
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Affiliation(s)
- X Nirmala
- Center for Medical, Agricultural, and Veterinary Entomology, Agricultural Research Service, U.S. Department of Agriculture, Gainesville, FL 32608, USA
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193
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Nguyen-Khuong T, White MY, Hung TT, Seeto S, Thomas ML, Fitzgerald AM, Martucci CE, Luk S, Pang SF, Russell PJ, Walsh BJ. Alterations to the protein profile of bladder carcinoma cell lines induced by plant extract MINA-05 in vitro. Proteomics 2009; 9:1883-92. [PMID: 19294694 DOI: 10.1002/pmic.200700839] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2007] [Indexed: 11/08/2022]
Abstract
Bladder cancer (BLCa) is a severe urological cancer of both men and women that commonly recurs and once invasive, is difficult to treat. MINA-05 (CK Life Sciences Int'l, Hong Kong) is a derivative of complex botanical extracts, shown to reduce cellular proliferation of bladder and prostate carcinomas. We tested the effects of MINA-05 against human BLCa cell sublines, B8, B8-RSP-GCK, B8-RSP-LN and C3, from a transitional cell carcinoma, grade IV, to determine the molecular targets of treatment by observing the cellular protein profile. Cells were acclimatised for 48 h then treated for 72 h with concentrations of MINA-05 reflecting 1/2 IC(50), IC(50) and 2 x IC(50) (n = 3) or with vehicle, (0.5% DMSO). Dose-dependant changes in protein abundance were detected and characterised using 2-dimensional electrophoresis and MS. We identified 10 proteins that underwent changes in abundance, pI and/or molecular mass in response to treatment. MINA-05 was shown to influence proteins across numerous functional classes including cytoskeletal proteins, energy metabolism proteins, protein degradation proteins and tumour suppressors, suggesting a global impact on these cell lines. This study implies that the ability of MINA-05 to retard cellular proliferation is attributed to its ability to alter cell cycling, metabolism, protein degradation and the cancer cell environment.
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194
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Powell A, Dupré J. From molecules to systems: the importance of looking both ways. STUDIES IN HISTORY AND PHILOSOPHY OF BIOLOGICAL AND BIOMEDICAL SCIENCES 2009; 40:54-64. [PMID: 19268874 DOI: 10.1016/j.shpsc.2008.12.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Although molecular biology has meant different things at different times, the term is often associated with a tendency to view cellular causation as conforming to simple linear schemas in which macro-scale effects are specified by micro-scale structures. The early achievements of molecular biologists were important for the formation of such an outlook, one to which the discovery of recombinant DNA techniques, and a number of other findings, gave new life even after the complexity of genotype-phenotype relations had become apparent. Against this background we outline how a range of scientific developments and conceptual considerations can be regarded as enabling and perhaps necessitating contemporary systems approaches. We suggest that philosophical ideas have a valuable part to play in making sense of complex scientific and disciplinary issues.
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Affiliation(s)
- Alexander Powell
- ESRC Centre for Genomics in Society, University of Exeter, Byrne House, St German's Road, Exeter, Devon EX4 4PJ, UK.
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195
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Milano A, Perri F, Caponigro F. The ubiquitin-proteasome system as a molecular target in solid tumors: an update on bortezomib. Onco Targets Ther 2009; 2:171-8. [PMID: 20616904 PMCID: PMC2886336 DOI: 10.2147/ott.s4503] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Indexed: 11/23/2022] Open
Abstract
The ubiquitin-proteasome system has become a promising molecular target in cancer therapy due to its critical role in cellular protein degradation, interaction with cell cycle and apoptosis regulation, and unique mechanism of action. Bortezomib (PS-341) is a potent and specific reversible proteasome inhibitor, which has shown strong in vitro antitumor activity as single agent and in combination with other cytotoxic drugs in a broad spectrum of hematological and solid malignancies. In preclinical studies, bortezomib induced apoptosis of malignant cells through the inhibition of NF-|B and stabilization of pro-apoptotic proteins. Bortezomib also promotes chemo- and radiosensitization of malignant cells in vitro and inhibits tumor growth in murine xenograft models. The proteasome has been established as a relevant target in hematologic malignancies and bortezomib has been approved for the treatment of multiple myeloma. This review summarizes recent data from clinical trials in solid tumors.
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Affiliation(s)
- A Milano
- Sandro Pitigliani Medical Oncology Unit, Department of Oncology, Hospital of Prato, Istituto Toscano Tumori, Prato, Italy
| | - F Perri
- Head and Neck Medical Oncology Unit, National Tumour Institute of Naples, Naples, Italy
| | - F Caponigro
- Head and Neck Medical Oncology Unit, National Tumour Institute of Naples, Naples, Italy
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196
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Csibi A, Leibovitch MP, Cornille K, Tintignac LA, Leibovitch SA. MAFbx/Atrogin-1 Controls the Activity of the Initiation Factor eIF3-f in Skeletal Muscle Atrophy by Targeting Multiple C-terminal Lysines. J Biol Chem 2009; 284:4413-21. [DOI: 10.1074/jbc.m807641200] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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197
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Abstract
The 1940s marked the beginning of an era of important discoveries that contributed to modern concepts underlying the current practice of cancer chemotherapy, such as the log kill hypothesis reported by Skipper, the Norton-Simon hypothesis, and the Goldie-Coldman hypothesis. The early success of nitrogen mustards and antifolates in the treatment of hematologic malignancies paved the way for drug discovery platforms, which resulted in the generation of more drugs that nonetheless predominantly are genotoxic. The turn of the new millennium marked a new phase in the evolution of cancer chemotherapy. Scientific progress in the preceding 60 years elucidated the important ideas behind tumor microenvironment and 'targeted' therapy that had their inception in the late 19th century. Breakthroughs in molecular biology have paved the way for the development of novel agents that modulate the dysregulated molecular pathways implicated in carcinogenesis. The key approaches and evidence pertinent to the clinical development of these novel agents are presented in this review.
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Affiliation(s)
- Grace K Dy
- Department of Medicine, Roswell Park Cancer Institute, Buffalo, NY 14263, USA
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198
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Abstract
AbstractThe first part of this review is concerned with the balance between N input and output as urinary urea. I start with some observations on classical biochemical studies of the operation of the urea cycle. According to Krebs, the cycle is instantaneous and automatic, as a result of the irreversibility of the first enzyme, carbamoyl-phosphate synthetase 1 (EC6.3.5.5; CPS-I), and it should be able to handle many times the normal input to the cycle. It is now generally agreed that acetyl glutamate is a necessary co-factor for CPS-1, but not a regulator. There is abundant evidence that changes in dietary protein supply induce coordinated changes in the amounts of all five urea-cycle enzymes. How this coordination is achieved, and why it should be necessary in view of the properties of the cycle mentioned above, is unknown. At the physiological level it is not clear how a change in protein intake is translated into a change of urea cycle activity. It is very unlikely that the signal is an alteration in the plasma concentration either of total amino-N or of any single amino acid. The immediate substrates of the urea cycle are NH3and aspartate, but there have been no measurements of their concentration in the liver in relation to urea production. Measurements of urea kinetics have shown that in many cases urea production exceeds N intake, and it is only through transfer of some of the urea produced to the colon, where it is hydrolysed to NH3, that it is possible to achieve N balance. It is beginning to look as if this process is regulated, possibly through the operation of recently discovered urea transporters in the kidney and colon. The second part of the review deals with the synthesis and breakdown of protein. The evidence on whole-body protein turnover under a variety of conditions strongly suggests that the components of turnover, including amino acid oxidation, are influenced and perhaps regulated by amino acid supply or amino acid concentration, with insulin playing an important but secondary role. Molecular biology has provided a great deal of information about the complex processes of protein synthesis and breakdown, but so far has nothing to say about how they are coordinated so that in the steady state they are equal. A simple hypothesis is proposed to fill this gap, based on the self-evident fact that for two processes to be coordinated they must have some factor in common. This common factor is the amino acid pool, which provides the substrates for synthesis and represents the products of breakdown. The review concludes that although the achievement and maintenance of N balance is a fact of life that we tend to take for granted, there are many features of it that are not understood, principally the control of urea production and excretion to match the intake, and the coordination of protein synthesis and breakdown to maintain a relatively constant lean body mass.
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199
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Cheroni C, Marino M, Tortarolo M, Veglianese P, De Biasi S, Fontana E, Zuccarello LV, Maynard CJ, Dantuma NP, Bendotti C. Functional alterations of the ubiquitin-proteasome system in motor neurons of a mouse model of familial amyotrophic lateral sclerosis. Hum Mol Genet 2008; 18:82-96. [PMID: 18826962 DOI: 10.1093/hmg/ddn319] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In familial and sporadic amyotrophic lateral sclerosis (ALS) and in rodent models of the disease, alterations in the ubiquitin-proteasome system (UPS) may be responsible for the accumulation of potentially harmful ubiquitinated proteins, leading to motor neuron death. In the spinal cord of transgenic mice expressing the familial ALS superoxide dismutase 1 (SOD1) gene mutation G93A (SOD1G93A), we found a decrease in constitutive proteasome subunits during disease progression, as assessed by real-time PCR and immunohistochemistry. In parallel, an increased immunoproteasome expression was observed, which correlated with a local inflammatory response due to glial activation. These findings support the existence of proteasome modifications in ALS vulnerable tissues. To functionally investigate the UPS in ALS motor neurons in vivo, we crossed SOD1G93A mice with transgenic mice that express a fluorescently tagged reporter substrate of the UPS. In double-transgenic Ub(G76V)-GFP /SOD1G93A mice an increase in Ub(G76V)-GFP reporter, indicative of UPS impairment, was detectable in a few spinal motor neurons and not in reactive astrocytes or microglia, at symptomatic stage but not before symptoms onset. The levels of reporter transcript were unaltered, suggesting that the accumulation of Ub(G76V)-GFP was due to deficient reporter degradation. In some motor neurons the increase of Ub(G76V)-GFP was accompanied by the accumulation of ubiquitin and phosphorylated neurofilaments, both markers of ALS pathology. These data suggest that UPS impairment occurs in motor neurons of mutant SOD1-linked ALS mice and may play a role in the disease progression.
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Affiliation(s)
- Cristina Cheroni
- Laboratory of Molecular Neurobiology, Department of Neuroscience, Mario Negri Institute for Pharmacological Research, Via La Masa, 19, 20156 Milan, Italy
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Sarközi R, Perco P, Hochegger K, Enrich J, Wiesinger M, Pirklbauer M, Eder S, Rudnicki M, Rosenkranz AR, Mayer B, Mayer G, Schramek H. Bortezomib-Induced Survival Signals and Genes in Human Proximal Tubular Cells. J Pharmacol Exp Ther 2008; 327:645-56. [DOI: 10.1124/jpet.108.142604] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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