201
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García-Cao I, Duran A, Collado M, Carrascosa MJ, Martín-Caballero J, Flores JM, Diaz-Meco MT, Moscat J, Serrano M. Tumour-suppression activity of the proapoptotic regulator Par4. EMBO Rep 2005; 6:577-83. [PMID: 15877079 PMCID: PMC1369092 DOI: 10.1038/sj.embor.7400421] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2005] [Revised: 03/17/2005] [Accepted: 04/13/2005] [Indexed: 11/09/2022] Open
Abstract
The proapoptotic protein encoded by Par4 (prostate apoptosis response 4) has been implicated in tumour suppression, particularly in the prostate. We report here that Par4-null mice are prone to develop tumours, both spontaneously and on carcinogenic treatment. The endometrium and prostate of Par4-null mice were particularly sensitive to the development of proliferative lesions. Most (80%) Par4-null females presented endometrial hyperplasia by 9 months of age, and a significant proportion (36%) developed endometrial adenocarcinomas after 1 year of age. Similarly, Par4-null males showed a high incidence of prostate hyperplasia and prostatic intraepithelial neoplasias, and were extraordinarily sensitive to testosterone-induced prostate hyperplasia. Finally, the uterus and prostate of young Par4-null mice have increased levels of the apoptosis inhibitor XIAP (X-chromosome-linked inhibitor of apoptosis), supporting the previously proposed function of Par4 as an inhibitor of the (zeta)PKC (atypical protein kinase)-NF-(kappa)B (nuclear factor-(kappa)B)-XIAP pathway. These data show that Par4 has an important role in tumour suppression, with a particular relevance in the endometrium and prostate.
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Affiliation(s)
- Isabel García-Cao
- Spanish National Cancer Center (CNIO), 3 Melchor Fernandez Almagro Street, Madrid 28029, Spain
| | - Angeles Duran
- Center of Molecular Biology ‘Severo Ochoa' (UAM-CSIC), Madrid 28049, Spain
| | - Manuel Collado
- Spanish National Cancer Center (CNIO), 3 Melchor Fernandez Almagro Street, Madrid 28029, Spain
| | | | - Juan Martín-Caballero
- Spanish National Cancer Center (CNIO), 3 Melchor Fernandez Almagro Street, Madrid 28029, Spain
| | - Juana M. Flores
- Department of Animal Surgery and Medicine, Complutense University, Madrid 28040, Spain
| | - Maria T. Diaz-Meco
- Center of Molecular Biology ‘Severo Ochoa' (UAM-CSIC), Madrid 28049, Spain
| | - Jorge Moscat
- Center of Molecular Biology ‘Severo Ochoa' (UAM-CSIC), Madrid 28049, Spain
| | - Manuel Serrano
- Spanish National Cancer Center (CNIO), 3 Melchor Fernandez Almagro Street, Madrid 28029, Spain
- Tel: +34 917 328 032; Fax: +34 917 328 028; E-mail:
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202
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Zhang P, Chan J, Dragoi AM, Gong X, Ivanov S, Li ZW, Chuang T, Tuthill C, Wan Y, Karin M, Chu WM. Activation of IKK by thymosin alpha1 requires the TRAF6 signalling pathway. EMBO Rep 2005; 6:531-7. [PMID: 15905851 PMCID: PMC1369095 DOI: 10.1038/sj.embor.7400433] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2004] [Revised: 04/19/2005] [Accepted: 04/20/2005] [Indexed: 11/08/2022] Open
Abstract
Thymosin alpha1 (T(alpha)1) is noted for its immunomodulatory activities and therapeutic potential in treatment of infectious diseases and cancer. However, the molecular mechanism of its effectiveness is not completely understood. Here, we report that T(alpha)1 induces interleukin (IL)-6 expression through the I(kappa)B kinase (IKK) and nuclear factor-(kappa)B (NF-(kappa)B) pathway. Using IKK(beta)-deficient bone-marrow-derived macrophages and mouse embryo fibroblasts (MEFs), we show that IKK(beta) is essential for IKK and NF-(kappa)B activation as well as efficient IL-6 induction. Further analysis using tumour necrosis factor receptor-associated factor 6 (TRAF6)-deficient MEFs shows that TRAF6 is crucial for activation of IKK and induction of IL-6 by Talpha1. Intriguingly, T(alpha)1 triggers protein kinase C (PKC)iota/zeta activation, which is TRAF6 dependent and involves IKK. In addition, T(alpha)1 induces the formation of a signalsome composed of TRAF6, p62 and PKC(iota)/zeta as well as IKK. Thus, our study identifies T(alpha)1 as a unique activator of the TRAF6 signal pathway and provides a cohesive interpretation of the molecular basis of the therapeutic utility of T(alpha)1.
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Affiliation(s)
- Ping Zhang
- Department of Molecular Microbiology and Immunology, Brown University, Providence, Rhode Island 02912, USA
| | - Justin Chan
- Department of Molecular Microbiology and Immunology, Brown University, Providence, Rhode Island 02912, USA
| | - Ana-Maria Dragoi
- Department of Molecular Microbiology and Immunology, Brown University, Providence, Rhode Island 02912, USA
| | - Xing Gong
- Department of Medicine, University of California at San Diego, La Jolla, California 92093, USA
| | - Stanimir Ivanov
- Department of Molecular Microbiology and Immunology, Brown University, Providence, Rhode Island 02912, USA
| | - Zhi-Wei Li
- Moffitt Cancer Center and Research Institute, SRB-22344, 3011 West Holly Drive, Tampa, Florida 33612, USA
| | - Tsheng Chuang
- Department of Immunology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
| | | | - Yinsheng Wan
- Department of Biology, Providence College, North Providence, Rhode Island 02918, USA
| | - Michael Karin
- Department of Pharmacology, University of California at San Diego, La Jolla, California 92093, USA
| | - Wen-Ming Chu
- Department of Molecular Microbiology and Immunology, Brown University, Providence, Rhode Island 02912, USA
- Tel: +1 401 863 9786; Fax: +1 401 863 1971; E-mail:
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203
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Magid R, Davies PF. Endothelial protein kinase C isoform identity and differential activity of PKCzeta in an athero-susceptible region of porcine aorta. Circ Res 2005; 97:443-9. [PMID: 16051884 PMCID: PMC3057121 DOI: 10.1161/01.res.0000179767.37838.60] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Endothelial protein kinase C (PKC) signaling was investigated in different regions of normal porcine aorta. The locations map to differential atherosclerotic susceptibility and correlate with sites of disturbed (DF) or undisturbed (UF) local flow profiles. Endothelial lysates were isolated from the inner curvature of the aortic arch (DF; athero-susceptible) and a nearby UF region of the descending thoracic aorta (UF; athero-protected), and in some experiments a distant athero-protected UF site, the common carotid artery. Total endothelial PKC activity in the DF regions was 145% to 240% of that in both UF locations (P<0.05), whereas the UF regions were not significantly different from each other. PKC protein isoforms alpha, beta, epsilon, iota, lambda, and zeta were expressed in similar proportions in both aortic regions, suggesting that differences of kinase activity were not directly attributable to expression levels. Inhibition of members of the "conventional" and "novel" PKC families had no differential effect on regional kinase activity. However, inhibition of PKCzeta, a member of the "atypical" PKC family, reduced the DF lysate kinase activity to that of UF levels (NS P=0.35). Differential phosphorylation of PKCzeta Thr410 and Thr560, along with increased levels of PKCzeta degradation products in UF endothelial lysates, suggested posttranslational modification of PKCzeta as the basis for site-specific differences in vivo. Steady-state regional heterogeneity of an important family of regulatory proteins in intact arterial endothelium in vivo may link localized athero-susceptibility and the associated hemodynamic environment.
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Affiliation(s)
- Richard Magid
- Institute for Medicine and Engineering, Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104-6383, USA.
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204
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Regala RP, Weems C, Jamieson L, Copland JA, Thompson EA, Fields AP. Atypical protein kinase Ciota plays a critical role in human lung cancer cell growth and tumorigenicity. J Biol Chem 2005; 280:31109-15. [PMID: 15994303 DOI: 10.1074/jbc.m505402200] [Citation(s) in RCA: 159] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Atypical protein kinase C (aPKC) isozymes function in epithelial cell polarity, proliferation, and survival and have been implicated in cellular transformation. However, the role of these enzymes in human cancer is largely unexplored. Here, we report that aPKCiota is highly expressed in human non-small cell lung cancer cell lines, whereas the closely related aPKC isozyme PKCzeta is undetectable in these cells. Disruption of PKCiota signaling reveals that PKCiota is dispensable for adherent growth of non-small cell lung cancer cells but is required for transformed growth in soft agar in vitro and for tumorigenicity in vivo. Molecular dissection of signaling down-stream of PKCiota demonstrates that Rac1 is a critical molecular target for PKCiota-dependent transformation, whereas PKCiota is not necessary for NFkappaB activation in vitro or in vivo. Expression of the PB1 domain of PKCiota (PKCiota-(1-113)) blocks PKCiota-dependent Rac1 activity and inhibits cellular transformation indicating a role for this domain in the transforming activity of PKCiota. Taken together, our data demonstrate that PKCiota is a critical lung cancer gene that activates a Rac1-->Pak-->Mek1,2-->Erk1,2 signaling pathway required for transformed growth. Our data indicate that PKCiota may be an attractive molecular target for mechanism-based therapies for treatment of lung cancer.
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Affiliation(s)
- Roderick P Regala
- Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center, Jacksonville, Florida 32224, USA
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205
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Todorov VT, Völkl S, Friedrich J, Kunz-Schughart LA, Hehlgans T, Vermeulen L, Haegeman G, Schmitz ML, Kurtz A. Role of CREB1 and NFκB-p65 in the Down-regulation of Renin Gene Expression by Tumor Necrosis Factor α. J Biol Chem 2005; 280:24356-62. [PMID: 15857826 DOI: 10.1074/jbc.m502968200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Tumor necrosis factor-alpha (TNFalpha) is a potent inhibitor of renin gene expression in renal juxtaglomerular cells. We have found that TNFalpha suppresses renin transcription via transcription factor NFkappaB, which targets a cAMP responsive element (CRE) in the renin promoter. Here we aimed to further clarify the role of NFkappaB and the canonical CRE-binding proteins of the CRE-binding protein/activating transcription factor (CREB/ATF) family in the inhibition of renin gene expression by TNFalpha in the juxtaglomerular cell line As4.1. TNFalpha caused a moderate decrease in the binding of CREB1 to its cognate CRE DNA binding site. On the other hand, NFkappaB-p65 transcriptional activity was substantially reduced by TNFalpha, which targeted a trans-activation domain at the very C terminus of the p65 molecule. Our results suggest that TNFalpha inhibits renin gene expression by decreasing the transactivating capacity of NFkappaB-p65 and partially by attenuating CREB1 binding to CRE.
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Affiliation(s)
- Vladimir T Todorov
- Institute of Physiology, Institute of Pathology, and Department of Immunology, Regensburg University, D-93040 Regensburg, Germany.
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206
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Martin P, Villares R, Rodriguez-Mascarenhas S, Zaballos A, Leitges M, Kovac J, Sizing I, Rennert P, Márquez G, Martínez-A C, Diaz-Meco MT, Moscat J. Control of T helper 2 cell function and allergic airway inflammation by PKCzeta. Proc Natl Acad Sci U S A 2005; 102:9866-71. [PMID: 15987782 PMCID: PMC1174981 DOI: 10.1073/pnas.0501202102] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Asthma is a disease of chronic airway inflammation in which T helper (Th) 2 cells play a critical role. The molecular mechanisms controlling Th2 differentiation and function are of paramount importance in biology and immunology. PKCzeta has been implicated in the regulation of apoptosis and NF-kappaB, as well as in the control of T-dependent responses, although no defects were detected in naïve T cells from PKCzeta-/- mice. Here, we report that PKCzeta is critical for IL-4 signaling and Th2 differentiation. Thus, PKCzeta levels are increased during Th2 differentiation, but not Th1 differentiation, of CD4+ T cells, and the loss of PKCzeta impairs the secretion of Th2 cytokines in vitro and in vivo, as well as the nuclear translocation and tyrosine phosphorylation of Stat6 and Jak1 activation, essential downstream targets of IL-4 signaling. Moreover, PKCzeta-/- mice display dramatic inhibition of ovalbumin-induced allergic airway disease, strongly suggesting that PKCzeta can be a therapeutic target in asthma.
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Affiliation(s)
- Pilar Martin
- Centro de Biología Molecular Severo Ochoa and Departamento de Inmunologia y Oncologia-Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Cientificas, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid, Spain
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207
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Jenny M, Wrulich OA, Schwaiger W, Ueberall F. Relevance of atypical protein kinase C isotypes to the drug discovery process. Chembiochem 2005; 6:491-9. [PMID: 15712318 DOI: 10.1002/cbic.200400186] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Marcel Jenny
- Innsbruck Biocentre, Division of Medical Biochemistry, Innsbruck Medical School, Fritz-Pregl-Strasse 3, 6020 Innsbruck, Austria
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208
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Feng Y, Longmore GD. The LIM protein Ajuba influences interleukin-1-induced NF-kappaB activation by affecting the assembly and activity of the protein kinase Czeta/p62/TRAF6 signaling complex. Mol Cell Biol 2005; 25:4010-22. [PMID: 15870274 PMCID: PMC1087715 DOI: 10.1128/mcb.25.10.4010-4022.2005] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The Zyxin/Ajuba family of cytosolic LIM domain-containing proteins has the potential to shuttle from sites of cell adhesion into the nucleus and thus can be candidate transducers of environmental signals. To understand Ajuba's role in signal transduction pathways, we performed a yeast two-hybrid screen with the LIM domain region of Ajuba. We identified the atypical protein kinase C (aPKC) scaffold protein p62 as an Ajuba binding partner. A prominent function of p62 is the regulation of NF-kappaB activation in response to interleukin-1 (IL-1) and tumor necrosis factor signaling through the formation of an aPKC/p62/TRAF6 multiprotein signaling complex. In addition to p62, we found that Ajuba also interacted with tumor necrosis factor receptor-associated factor 6 (TRAF6) and PKCzeta. Ajuba recruits TRAF6 to p62 and in vitro activates PKCzeta activity and is a substrate of PKCzeta. Ajuba null mouse embryonic fibroblasts (MEFs) and lungs were defective in NF-kappaB activation following IL-1 stimulation, and in lung IKK activity was inhibited. Overexpression of Ajuba in primary MEFs enhances NF-kappaB activity following IL-1 stimulation. We propose that Ajuba is a new cytosolic component of the IL-1 signaling pathway modulating IL-1-induced NF-kappaB activation by influencing the assembly and activity of the aPKC/p62/TRAF6 multiprotein signaling complex.
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Affiliation(s)
- Yungfeng Feng
- Department of Medicine, Washington University, St. Louis, Missouri 63110, USA
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209
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Dallot E, Méhats C, Oger S, Leroy MJ, Breuiller-Fouché M. A role for PKCζ in the LPS-induced translocation NF-κB p65 subunit in cultured myometrial cells. Biochimie 2005; 87:513-21. [PMID: 15935276 DOI: 10.1016/j.biochi.2005.02.009] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2004] [Revised: 01/28/2005] [Accepted: 02/23/2005] [Indexed: 11/25/2022]
Abstract
Human myometrial cells respond to the endotoxin lipopolysaccharide (LPS) by activation of protein kinase C (PKC) zeta and nuclear translocation of the p65 subunit of NF-kB. Our first objective was to determine the expression of TLR4 in cultured myometrial cells. Positive immunoreactivity observed for TLR4 suggests that myometrial cells have the potential to respond to LPS. To confirm that LPS signals via TLR4, the ability of an anti-TLR4 neutralizing antibody to block LPS-induced translocation of p65 was demonstrated. To determine whether LPS-induced nuclear translocation of p65 is mediated through the PKC pathway, myometrial cells were treated with various inhibitors of the PKC isoforms already characterized in human myometrium. Neither the selective conventional PKC inhibitor nor the inhibitor of PKCdelta affected NF-kB activation. By contrast, we found that treatment of myometrial cells with an antisense against PKCzeta affect LPS-induced nuclear translocation of the p65 subunit of NF-kB. Accordingly, our data support the notion that PKCzeta is essential for LPS-induced NF-kB p65 subunit nuclear translocation in human myometrial cells.
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Affiliation(s)
- Emmanuelle Dallot
- Institut National de la Santé et de la Recherche Médicale, Inserm U427, Faculté des Sciences Pharmaceutiques et Biologiques, Université René Descartes, 4, avenue de l'Observatoire, 75006 Paris, France
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210
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Das S, Cho J, Lambertz I, Kelliher MA, Eliopoulos AG, Du K, Tsichlis PN. Tpl2/cot signals activate ERK, JNK, and NF-kappaB in a cell-type and stimulus-specific manner. J Biol Chem 2005; 280:23748-57. [PMID: 15833743 DOI: 10.1074/jbc.m412837200] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Macrophages and B-cells from Tpl2 knock-out mice exhibit a restricted defect in lipopolysaccharide and death receptor signaling that is limited to the activation of ERK. Here we show that Tpl2-/- MEFs exhibit defects in ERK, JNK, and NF-kappaB activation, or ERK activation only when stimulated with tumor necrosis factor-alpha (TNF-alpha) or interleukin-1beta, respectively. In addition, we show that the activation of Tpl2 by TNF-alpha depends on signals transduced by both TRAF2 and RIP1. Activated Tpl2 phosphorylates MKK4/SEK1 upstream of JNK and stimulates NF-kappaB DNA binding and transcriptional activity by mechanisms that are independent of the nuclear translocation of p50 and p65. Tpl2-transduced TNF-alpha signals instead promote the phosphorylation of p65 at Ser276 and modulate the spectrum of proteins associated with p65. Phosphorylation stimulates the transcriptional activity of NF-kappaB but does not affect its ability to bind DNA, which may be affected by the composition of the nuclear NF-kappaB complexes. These data confirm that defects caused by a single mutation may be cell-type and signal-specific and delineate the role of Tpl2 in the transduction of TNF-alpha signals that activate JNK and NF-kappaB in MEFs.
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Affiliation(s)
- Santasabuj Das
- Molecular Oncology Research Institute, Tufts-New England Medical Center, Boston, Massachusetts 02111, USA
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211
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Sun R, Gao P, Chen L, Ma D, Wang J, Oppenheim JJ, Zhang N. Protein kinase C zeta is required for epidermal growth factor-induced chemotaxis of human breast cancer cells. Cancer Res 2005; 65:1433-41. [PMID: 15735031 DOI: 10.1158/0008-5472.can-04-1163] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Chemotaxis plays an important role in cancer cell metastasis. In this study, we showed that epidermal growth factor (EGF) was a more potent chemoattractant than chemokine SDF-1alpha/CXCL12 for human breast cancer cell MDA-MB-231. Different inhibitors were used to evaluate the involvement of 12 protein kinase C (PKC) isotypes in the chemotactic signaling pathway. Chelerythrine chloride, an inhibitor of all PKC isotypes, blocked chemotaxis, whereas inhibitors of classic and novel PKC, such as Gö6976, Gö6850, or calphostin C, only impaired EGF-induced chemotaxis to a minor extent by not greater-than32% inhibition. These data suggested that atypical PKC were involved. The ligand-induced actin polymerization and cell adhesion were also similarly dependent on atypical PKC. Immunofluorescent staining showed an EGF-induced, LY294002-sensitive translocation of PKCzeta from the cytosol to the plasma membrane, indicating that EGF was capable of activating PKCzeta, probably via phosphoinositide 3 kinases. A myristoylated PKCzeta pseudosubstrate blocked the chemotaxis with an IC(50) of 20 mumol/L. To expand our investigation, we further showed that in MCF-7 and T47D, two additional human breast cancer cell lines, EGF-activated PKCzeta and the PKCzeta pseudosubstrate, inhibited chemotaxis. Taken together, our data suggest that PKCzeta is an essential component of the EGF-stimulated chemotactic signaling pathway in human breast cancer cells.
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Affiliation(s)
- Ronghua Sun
- Department of Chemical Biology and State Key Laboratory of Molecular Dynamic and Stable Structures, College of Chemistry and Laboratory of Medical Immunology, School of Basic Medical Science, Peking University, Beijing, China
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212
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Viatour P, Merville MP, Bours V, Chariot A. Phosphorylation of NF-kappaB and IkappaB proteins: implications in cancer and inflammation. Trends Biochem Sci 2005; 30:43-52. [PMID: 15653325 DOI: 10.1016/j.tibs.2004.11.009] [Citation(s) in RCA: 1160] [Impact Index Per Article: 61.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Nuclear factor-kappaB (NF-kappaB) is a transcription factor that has crucial roles in inflammation, immunity, cell proliferation and apoptosis. Activation of NF-kappaB mainly occurs via IkappaB kinase (IKK)-mediated phosphorylation of inhibitory molecules, including IkappaBalpha. Optimal induction of NF-kappaB target genes also requires phosphorylation of NF-kappaB proteins, such as p65, within their transactivation domain by a variety of kinases in response to distinct stimuli. Whether, and how, phosphorylation modulates the function of other NF-kappaB and IkappaB proteins, such as B-cell lymphoma 3, remains unclear. The identification and characterization of all the kinases known to phosphorylate NF-kappaB and IkappaB proteins are described here. Because deregulation of NF-kappaB and IkappaB phosphorylations is a hallmark of chronic inflammatory diseases and cancer, newly designed drugs targeting these constitutively activated signalling pathways represent promising therapeutic tools.
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Affiliation(s)
- Patrick Viatour
- Laboratory of Medical Chemistry and Human Genetics, CHU, Sart-Tilman, Center for Biomedical Integrated Genoproteomics, University of Liege, Belgium
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213
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Asehnoune K, Strassheim D, Mitra S, Yeol Kim J, Abraham E. Involvement of PKCα/β in TLR4 and TLR2 dependent activation of NF-κB. Cell Signal 2005; 17:385-94. [PMID: 15567069 DOI: 10.1016/j.cellsig.2004.08.005] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2004] [Revised: 08/18/2004] [Accepted: 08/19/2004] [Indexed: 01/23/2023]
Abstract
Protein kinase C (PKC)alpha/beta dependent signaling events downstream of TLR4 or TLR2 were investigated in neutrophils stimulated with LPS or PGN. Pretreatment of neutrophils with the structurally distinct PKCalpha/beta inhibitors Go6976 or GF109203X decreased nuclear translocation of NF-kappaB and production of the proinflammatory cytokine TNF-alpha. Inhibition of PKCalpha/beta also prevented LPS or PGN induced phosphorylation of IKKalpha/beta, phosphorylation and degradation of IkappaB-alpha, as well as phosphorylation of the p65 subunit of NF-kappaB. Activation of p38, JNK, and ERK 1/2 in response to TLR2 engagement was diminished in neutrophils in which PKCalpha/beta was inhibited. However, no alteration in the activation of these kinases was found in TLR4 stimulated neutrophils when PKCalpha/beta was blocked. Such results indicate that distinct intracellular signalling pathways leading to MAPK activation are induced by TLR4 and TLR2 stimulation. PKCalpha/beta can regulate NF-kappaB dependent transcription in neutrophils both by enhancing nuclear translocation of NF-kappaB and also by stimulating phosphorylation of the p65 subunit.
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Affiliation(s)
- Karim Asehnoune
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Health Sciences Center, Box C272, 4200 East 9th Ave, Denver, CO 80262, USA
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214
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Schmitz ML, Mattioli I, Buss H, Kracht M. NF-kappaB: a multifaceted transcription factor regulated at several levels. Chembiochem 2005; 5:1348-58. [PMID: 15457532 DOI: 10.1002/cbic.200400144] [Citation(s) in RCA: 196] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
NF-kappaB is a generic name for an evolutionarily conserved transcription-factor system that contributes to the mounting of an effective immune response but is also involved in the regulation of cell proliferation, development, and apoptosis. The implication of NF-kappaB in central biological processes and its extraordinary connectivity to other signaling pathways raise a need for highly controlled regulation of NF-kappaB activity at several levels. While all NF-kappaB activation pathways share a central and critical proteasome-mediated step that leads to the degradation of inhibitory proteins and the release of DNA-binding subunits, there is evidence for a downstream level of NF-kappaB regulation that employs several mechanisms. These include promoter-specific exchange of dimers and modification of the transactivating p65 subunit by phosphorylation, acetylation, ubiquitination, or prolyl isomerization. The signaling pathways and enzymes controlling this second level of regulation and their potential use as therapeutic targets for the treatment of NF-kappaB-associated pathologies are discussed here.
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Affiliation(s)
- M Lienhard Schmitz
- University of Bern, Department of Chemistry and Biochemistry, Freiestrasse 3, 3012 Bern, Switzerland.
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215
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Nhan TQ, Liles WC, Schwartz SM. Role of caspases in death and survival of the plaque macrophage. Arterioscler Thromb Vasc Biol 2005; 25:895-903. [PMID: 15718496 DOI: 10.1161/01.atv.0000159519.07181.33] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This review considers the role of macrophage cell death in formation of the necrotic core and in plaque progression, and lists many of the possible mediators of macrophage cell death. Among these, perhaps the most cited toxic agent is oxidized low-density lipoprotein (oxLDL). Whereas oxLDL can kill macrophage, and whereas the form of death is morphologically apoptotic, caspase inhibitors appear to be ineffective in preventing death. This finding is consistent with recent literature showing how the canonical caspase pathways are used for physiological cellular functions other than cell death. Plaque macrophages appear to be among the cells with this nonapoptotic signaling function for activated caspases. In many of the other cell types, caspase activation appears to play a critical role in cell differentiation. We discuss possible functions of plaque macrophage using the nondeath caspase pathway. Recent literature shows that physiological and developmental functions of many cell types require active caspases without progressing to cell death. We discuss the role of macrophage cell death in plaque progression, possible mediators of macrophage cell death, and the possible functions of plaque macrophage using the nondeath caspase pathway.
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Affiliation(s)
- Thomas Q Nhan
- Department of Pathology, University of Washington, Seattle, Wash 98195-4717, USA
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216
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Petit I, Goichberg P, Spiegel A, Peled A, Brodie C, Seger R, Nagler A, Alon R, Lapidot T. Atypical PKC-zeta regulates SDF-1-mediated migration and development of human CD34+ progenitor cells. J Clin Invest 2005; 115:168-76. [PMID: 15630457 PMCID: PMC539190 DOI: 10.1172/jci21773] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2004] [Accepted: 11/11/2004] [Indexed: 11/17/2022] Open
Abstract
The chemokine stromal cell-derived factor-1 (SDF-1) and its receptor, CXCR4, play a major role in migration, retention, and development of hematopoietic progenitors in the bone marrow. We report the direct involvement of atypical PKC-zeta in SDF-1 signaling in immature human CD34(+)-enriched cells and in leukemic pre-B acute lymphocytic leukemia (ALL) G2 cells. Chemotaxis, cell polarization, and adhesion of CD34(+) cells to bone marrow stromal cells were found to be PKC-zeta dependent. Overexpression of PKC-zeta in G2 and U937 cells led to increased directional motility to SDF-1. Interestingly, impaired SDF-1-induced migration of the pre-B ALL cell line B1 correlated with reduced PKC-zeta expression. SDF-1 triggered PKC-zeta phosphorylation, translocation to the plasma membrane, and kinase activity. Furthermore we identified PI3K as an activator of PKC-zeta, and Pyk-2 and ERK1/2 as downstream targets of PKC-zeta. SDF-1-induced proliferation and MMP-9 secretion also required PKC-zeta activation. Finally, we showed that in vivo engraftment, but not homing, of human CD34(+)-enriched cells to the bone marrow of NOD/SCID mice was PKC-zeta dependent and that injection of mice with inhibitory PKC-zeta pseudosubstrate peptides resulted in mobilization of murine progenitors. Our results demonstrate a central role for PKC-zeta in SDF-1-dependent regulation of hematopoietic stem and progenitor cell motility and development.
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Affiliation(s)
- Isabelle Petit
- Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel
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217
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Matsubara M, Tamura T, Ohmori K, Hasegawa K. Histamine H1 receptor antagonist blocks histamine-induced proinflammatory cytokine production through inhibition of Ca2+-dependent protein kinase C, Raf/MEK/ERK and IKK/IκB/NF-κB signal cascades. Biochem Pharmacol 2005; 69:433-49. [PMID: 15652235 DOI: 10.1016/j.bcp.2004.10.006] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2004] [Accepted: 10/20/2004] [Indexed: 11/23/2022]
Abstract
Histamine H1 receptor (H1R), a therapeutic target for alleviation of acute allergic reaction, may be also involved in mediating inflammatory responses via effects on cytokine production. However, the mechanisms whereby histamine induces cytokine production are poorly defined. In this study, we comprehensively investigated the signaling pathway involved in cytokine expression caused by histamine, using native human epidermal keratinocytes. We confirmed the expression of functional H1R by reverse transcription-polymerase chain reaction (RT-PCR), Western blotting and histamine-induced Ca(2+) elevation. Histamine induced concentration- and time-dependent production of granulocyte-macrophage-colony stimulating factor (GM-CSF), interleukin (IL)-8 and IL-6, which was completely blocked by olopatadine, an H1 antagonist. Histamine activated the phosphorylation of protein kinase C (PKC), c-Raf, mitogen-activated protein/extracellular signal-regulated kinase kinase (MEK), extracellular signal-regulated kinase (ERK), I kappa B kinase (IKK), inhibitory kappa B (I kappa B)-alpha and nuclear factor-KB (NF-kappa B) p65, which was inhibited by Ro-31-8220, a PKC inhibitor. Also, Ro-31-8220 significantly suppressed the expression of these cytokines. BAPTA-AM, an intracellular Ca(2+) chelator, also reduced PKC phosphorylation and cytokine expression. PD98059, a MEK inhibitor, and BAY 11-8702, an I kappa B-alpha inhibitor, reduced ERK and NF-kappa B cascade activation, respectively, with little effect on PKC phosphorylation. PD98059 preferentially inhibited GM-CSF production whereas BAY 11-8702 prevented IL-8 and IL-6 production. Furthermore, in addition to the above cytokines, histamine stimulated the biosynthesis and/or release of numerous keratinocyte-derived mediators, which are probably regulated by the ERK or NF-kappa B cascades. Our study suggests that histamine activates Ca(2+)-dependent PKC isoforms that play crucial roles in the activation of Raf/MEK/ERK and IKK/I kappa B/NF-kappa B cascades, leading to up-regulation of cytokine expression. Thus, the anti-inflammatory benefit of H1 antagonists may be in part due to prevention of cytokine production.
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Affiliation(s)
- Masahiro Matsubara
- Department of Pharmacology and Molecular Biology, Pharmaceutical Research Center, Kyowa Hakko Kogyo Co. Ltd., Shizuoka 411-8731, Japan.
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218
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del Rio R, Rincón M, Layseca-Espinosa E, Fierro NA, Rosenstein Y, Pedraza-Alva G. PKCtheta is required for the activation of human T lymphocytes induced by CD43 engagement. Biochem Biophys Res Commun 2005; 325:133-43. [PMID: 15522211 DOI: 10.1016/j.bbrc.2004.10.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2004] [Indexed: 12/12/2022]
Abstract
The turnover of phosphoinositides leading to PKC activation constitutes one of the principal axes of intracellular signaling. In T lymphocytes, the enhanced and prolonged PKC activation resulting from the engagement of the TcR and co-receptor molecules ensures a productive T cell response. The CD43 co-receptor promotes activation and proliferation, by inducing IL-2 secretion and CD69 expression. CD43 engagement has been shown to promote phosphoinositide turnover and DAG production. Moreover, PKC activation was found to be required for the activation of the MAP kinase pathway in response to CD43 ligation. Here we show that CD43 engagement led to the membrane translocation and enzymatic activity of specific PKC isoenzymes: cPKC (alpha/beta), nPKC (epsilon and theta;), aPKC (zeta) and PKCmu. We also show that activation of PKCtheta; resulting from CD43 ligation induced CD69 expression through an ERK-dependent pathway leading to AP-1, NF-kappaB activation and an ERK independent pathway promoting NFAT activation. Together, these data suggest that PKCtheta; plays a critical role in the co-stimulatory functions of CD43 in human T cells.
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Affiliation(s)
- Roxana del Rio
- Instituto de Biotecnología/Universidad Nacional Autónoma de México, AP 510-3 Cuernavaca, Mor. 62250, Mexico
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219
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Brown TT, Zelnik DL, Dobs AS, Evans DB, Chiao PJ. Fish oil supplementation in the treatment of cachexia in pancreatic cancer patients. INTERNATIONAL JOURNAL OF GASTROINTESTINAL CANCER 2005. [PMID: 15361649 DOI: 10.1385/ijgc:] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Patients with pancreatic cancer often experience a loss of weight and appetite, known as the anorexia-cachexia syndrome, which is associated with decreased quality of life and reduced survival. Research into the biological mechanisms of cachexia has demonstrated that an array of inflammatory mediators and tumor-derived factors cause appetite suppression, skeletal muscle proteolysis, and lipolysis,producing an overall hypercatabolic state that contributes to loss of fat and lean body mass. Omega-3 polyunsaturated fatty acids (n-3 PUFAs) have been shown to modulate levels of proinflammatory cytokines, hepatic acute phase proteins, eicosanoids, and tumor-derived factors in animal models of cancer and may reverse some aspects of the process of cachexia. Results of clinical trials of n-3 PUFAs in the form of fish oils have been mixed, but should encourage further investigation into dietary fish oil supplementation, including the most effective route of administration and the proper dosage to promote optimal weight maintenance and to limit side effects. Concerns about standardization and quality control should also be considered. With the current available evidence, a recommendation for the use of omega 3 polyunsaturated fatty acids in pancreatic cancer cachexia is premature.
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Affiliation(s)
- Todd T Brown
- Johns Hopkins University School of Medicine, Division of Endocrinology and Metabolism, Center for Complementary and Alternative Medicine, Baltimore, MD 21287, USA
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220
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Petit I, Goichberg P, Spiegel A, Peled A, Brodie C, Seger R, Nagler A, Alon R, Lapidot T. Atypical PKC-ζ regulates SDF-1–mediated migration and development of human CD34+ progenitor cells. J Clin Invest 2005. [DOI: 10.1172/jci200521773] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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221
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Haefner B. The transcription factor NF-kappaB as drug target. PROGRESS IN MEDICINAL CHEMISTRY 2005; 43:137-88. [PMID: 15850825 DOI: 10.1016/s0079-6468(05)43005-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Affiliation(s)
- Burkhard Haefner
- Department of Inflammation, Johnson & Johnson Pharmaceutical Research and Development, A Division of Janssen Pharmaceutica, Beerse, Belgium
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222
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McCarty MF. Potential utility of natural polyphenols for reversing fat-induced insulin resistance. Med Hypotheses 2005; 64:628-35. [PMID: 15617879 DOI: 10.1016/j.mehy.2003.11.042] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2003] [Accepted: 11/21/2003] [Indexed: 12/13/2022]
Abstract
There is intriguing recent evidence that the beta subunit of the signalsome--IKKbeta, a crucial catalyst of NF-kappaB activation--is an obligate mediator of the disruption of insulin signaling induced by excessive exposure of tissues to free fatty acids and by hypertrophy of adipocytes. Thus, agents which safely inhibit or suppress the activation of IKKbeta may have utility for reversing insulin resistance syndrome and aiding control of type 2 diabetes. Two natural agents which can achieve this effect in vitro--and which may have clinical potential in this regard--are the polyphenols resveratrol and silibinin. To date, limited absorbability and/or rapid glucuronidation have prevented these agents from achieving full therapeutic utility, but, by administering these agents in optimally absorbable forms, and co-administering inhibitors of glucuronidation such as probenecid, it may prove feasible to make these agents more clinically viable. Oral silibinin, in the guise of the milk thistle extract silymarin, already has documented clinical utility in a range of hepatic disorders, and recent evidence that dietary silibinin can inhibit the growth of certain cancers in rodents suggests that this agent may indeed have clinical potential as an IKKbeta inhibitor. A report that silymarin has a favorable impact on glycemic and lipidemic control in type 2 diabetics with cirrhosis, may or may not be indicative of IKKbeta inhibition in skeletal muscle and adipocytes. In light of the fact that IKKbeta plays a crucial role, not only in the induction of insulin resistance, but also atherogenesis, a host of inflammatory disorders, and the survival and spread of cancer, the development of pharmaceutical agents that could safely and feasibly achieve a down-regulation of IKKbeta activity would have broad therapeutic and preventive implications.
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Affiliation(s)
- Mark F McCarty
- Pantox Laboratories, 4622 Santa Fe St., San Diego, CA 92109, USA.
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223
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Nguyen BT, Dessauer CW. Relaxin stimulates protein kinase C zeta translocation: requirement for cyclic adenosine 3',5'-monophosphate production. Mol Endocrinol 2004; 19:1012-23. [PMID: 15604116 DOI: 10.1210/me.2004-0279] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Relaxin is a polypeptide hormone that activates the leucine-rich repeat containing G protein-coupled receptors, LGR7 and LGR8. In an earlier study, we reported that relaxin produces a biphasic time course and the second wave of cAMP is highly sensitive to phosphoinositide-3 kinase inhibitors (LY294002 and wortmannin). LY294002 inhibits relaxin-mediated increases in cAMP production by 40-50% across a large range of relaxin concentrations. Here we show that protein kinase C zeta (PKCzeta) is a component of relaxin signaling in THP-1 cells. Sphingomyelinase increases cAMP production due to the release of ceramide, a direct activator of PKCzeta. Chelerythrine chloride (a general PKC inhibitor) inhibits relaxin induced cAMP production to the same degree (approximately 40%) as LY294002. Relaxin stimulates PKCzeta translocation to the plasma membrane in THP-1, MCF-7, pregnant human myometrial 1-31, and mouse mesangial cells, as shown by immunocytochemistry. PKCzeta translocation is phosphoinositide-3 kinase dependent and independent of cAMP production. Antisense PKCzeta oligodeoxynucleotides (PKCzeta-ODNs) deplete both PKCzeta transcript and protein levels in THP-1 cells. PKCzeta-ODNs abolish relaxin-mediated PKCzeta translocation and inhibit relaxin stimulation of cAMP by 40%, as compared with mock and random ODN controls. Treatment with LY294002 in the presence of PKCzeta-ODNs results in little further inhibition. In summary, we present a novel role for PKCzeta in relaxin-mediated stimulation of cAMP.
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Affiliation(s)
- Bao T Nguyen
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, Texas 77030, USA
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224
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Durán A, Rodriguez A, Martin P, Serrano M, Flores JM, Leitges M, Diaz-Meco MT, Moscat J. Crosstalk between PKCzeta and the IL4/Stat6 pathway during T-cell-mediated hepatitis. EMBO J 2004; 23:4595-605. [PMID: 15526032 PMCID: PMC533053 DOI: 10.1038/sj.emboj.7600468] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2004] [Accepted: 10/11/2004] [Indexed: 01/08/2023] Open
Abstract
PKCzeta is required for nuclear factor kappa-B (NF-kappaB) activation in several cell systems. NF-kappaB is a suppressor of liver apoptosis during development and in concanavalin A (ConA)-induced T-cell-mediated hepatitis. Here we show that PKCzeta-/- mice display inhibited ConA-induced NF-kappaB activation and reduced damage in liver. As the IL-4/Stat6 pathway is necessary for ConA-induced hepatitis, we addressed here the potential role of PKCzeta in this cascade. Interestingly, the loss of PKCzeta severely attenuated serum IL-5 and liver eotaxin-1 levels, two critical mediators of liver damage. Stat6 tyrosine phosphorylation and Jak1 activation were ablated in the liver of ConA-injected PKCzeta-/- mice and in IL-4-stimulated PKCzeta-/- fibroblasts. PKCzeta interacts with and phosphorylates Jak1 and PKCzeta activity is required for Jak1 function. In contrast, Par-4-/- mice have increased sensitivity to ConA-induced liver damage and IL-4 signaling. This unveils a novel and critical involvement of PKCzeta in the IL-4/Stat6 signaling pathway in vitro and in vivo.
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Affiliation(s)
- Angeles Durán
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain
| | - Angelina Rodriguez
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain
| | - Pilar Martin
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain
| | - Manuel Serrano
- Centro Nacional de Investigaciones Oncológicas, Madrid, Spain
| | - Juana Maria Flores
- Departamento de Medicina y Cirugia Animal, Facultad de Veterinaria, Universidad Complutense, Madrid, Spain
| | - Michael Leitges
- Max-Planck-Institut für Experimentelle Endokrinologie, Hannover, Germany
| | - María T Diaz-Meco
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain
| | - Jorge Moscat
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain
- Centro de Biologia Molecular Severo Ochoa (CBMSO), Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Canto Blanco, 28049 Madrid, Spain. Tel.: +34 91 397 8039; Fax: +34 91 761 6184; E-mail:
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225
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Louat T, Canitrot Y, Jousseaume S, Baudouin C, Canal P, Laurent G, Lautier D. Atypical protein kinase C stimulates nucleotide excision repair activity. FEBS Lett 2004; 574:121-5. [PMID: 15358551 DOI: 10.1016/j.febslet.2004.08.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2004] [Revised: 08/08/2004] [Accepted: 08/08/2004] [Indexed: 10/26/2022]
Abstract
Nucleotide excision repair (NER) deals with bulky DNA damages. However, the regulation of this process is still unclear. Here, we show that both cell resistance to genotoxic agents that generate DNA lesions corrected by NER and in vitro NER activity are correlated with atypical protein kinase C (PKC) zeta expression levels. Moreover, repair intermediates are produced and eliminated more rapidly in UV-irradiated PKCzeta-overexpressing cells. The expression levels of XPC and hHR23B, two NER proteins, are correlated with PKCzeta expression. Altogether, these results strongly suggest that PKCzeta could act as a modulator of NER activity by regulating the expression of XPC/hHR23B heterodimer.
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Affiliation(s)
- Thierry Louat
- INSERM U563, Centre de Physiopathologie de Toulouse Purpan, CHU Purpan, 31024 Toulouse Cedex, France
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226
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Abstract
The transcription factor NF-kappaB has been the focus of intense investigation for nearly two decades. Over this period, considerable progress has been made in determining the function and regulation of NF-kappaB, although there are nuances in this important signaling pathway that still remain to be understood. The challenge now is to reconcile the regulatory complexity in this pathway with the complexity of responses in which NF-kappaB family members play important roles. In this review, we provide an overview of established NF-kappaB signaling pathways with focus on the current state of research into the mechanisms that regulate IKK activation and NF-kappaB transcriptional activity.
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Affiliation(s)
- Matthew S Hayden
- Section of Immunobiology and Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520, USA
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227
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Buss H, Dörrie A, Schmitz ML, Hoffmann E, Resch K, Kracht M. Constitutive and interleukin-1-inducible phosphorylation of p65 NF-{kappa}B at serine 536 is mediated by multiple protein kinases including I{kappa}B kinase (IKK)-{alpha}, IKK{beta}, IKK{epsilon}, TRAF family member-associated (TANK)-binding kinase 1 (TBK1), and an unknown kinase and couples p65 to TATA-binding protein-associated factor II31-mediated interleukin-8 transcription. J Biol Chem 2004; 279:55633-43. [PMID: 15489227 DOI: 10.1074/jbc.m409825200] [Citation(s) in RCA: 300] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Phosphorylation of NF-kappaB p65(RelA) serine 536 is physiologically induced in response to a variety of proinflammatory stimuli, but the responsible pathways have not been conclusively unraveled, and the function of this phosphorylation is largely elusive. In contrast to previous studies, we found no evidence for a role of c-Jun N-terminal kinase, p38 kinase, extracellular signal-regulated kinase, or phosphatidylinositol 3-kinase in interleukin-1- or tumor necrosis factor-induced Ser-536 phosphorylation, as revealed by pharmacological inhibitors. We were not able to suppress Ser-536 phosphorylation by either RNA interference directed at IkappaB kinase (IKK)-alpha/beta (the best characterized Ser-536 kinases so far) or the IKKbeta inhibitor SC-514 or dominant negative mutants of either IKK. A green fluorescent protein p65 fusion protein was phosphorylated at Ser-536 in the absence of IKK activation, suggesting the existence of IKKalpha/beta-independent Ser-536 kinases. Chromatographic fractionation of cell extracts allowed the identification of two distinct enzymatic activities phosphorylating Ser-536. Peak 1 represents an unknown kinase, whereas peak 2 contained IKKalpha, IKKbeta, IKKepsilon, and TBK1. Overexpressed IKKepsilon and TBK1 phosphorylate Ser-536 in vivo and in vitro. Reconstitution of mutant p65 proteins in p65-deficient fibroblasts that either mimicked phosphorylation (S536D) or preserved a predicted hydrogen bond between Ser-536 and Asp-533 (S536N) revealed that phosphorylation of Ser-536 favors interleukin-8 transcription mediated by TATA-binding protein-associated factor II31, a component of TFIID. In the absence of phosphorylation, the hydrogen bond favors binding of the corepressor amino-terminal enhancer of split to the p65 terminal transactivation domain. Collectively, our results provide evidence for at least five kinases that converge on Ser-536 of p65 and a novel function for this phosphorylation site in the recruitment of components of the basal transcriptional machinery to the interleukin-8 promoter.
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Affiliation(s)
- Holger Buss
- Institute of Pharmacology, Medical School Hannover, Carl-Neuberg Strasse 1, D-30625 Hannover, Germany
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228
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Gajecka M, Yu W, Ballif BC, Glotzbach CD, Bailey KA, Shaw CA, Kashork CD, Heilstedt HA, Ansel DA, Theisen A, Rice R, Rice DPC, Shaffer LG. Delineation of mechanisms and regions of dosage imbalance in complex rearrangements of 1p36 leads to a putative gene for regulation of cranial suture closure. Eur J Hum Genet 2004; 13:139-49. [PMID: 15483646 DOI: 10.1038/sj.ejhg.5201302] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Structural chromosome abnormalities have aided in gene identification for over three decades. Delineation of the deletion sizes and rearrangements allows for phenotype/genotype correlations and ultimately assists in gene identification. In this report, we have delineated the precise rearrangements in four subjects with deletions, duplications, and/or triplications of 1p36 and compared the regions of imbalance to two cases recently published. Fluorescence in situ hybridization (FISH) analysis revealed the size, order, and orientation of the duplicated/triplicated segments in each subject. We propose a premeiotic model for the formation of these complex rearrangements in the four newly ascertained subjects, whereby a deleted chromosome 1 undergoes a combination of multiple breakage-fusion-bridge (BFB) cycles and inversions to produce a chromosome arm with a complex rearrangement of deleted, duplicated and triplicated segments. In addition, comparing the six subjects' rearrangements revealed a region of overlap that when triplicated is associated with craniosynostosis and when deleted is associated with large, late-closing anterior fontanels. Within this region are the MMP23A and -B genes. We show MMP23 gene expression at the cranial sutures and we propose that haploinsufficiency results in large, late-closing anterior fontanels and overexpression results in craniosynostosis. These data emphasize the important role of cytogenetics in investigating and uncovering the etiologies of human genetic disease, particularly cytogenetic imbalances that reveal potentially dosage-sensitive genes.
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Affiliation(s)
- Marzena Gajecka
- Health Research and Education Center, Washington State University, Spokane, WA 99210, USA
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229
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Buss H, Dörrie A, Schmitz ML, Frank R, Livingstone M, Resch K, Kracht M. Phosphorylation of serine 468 by GSK-3beta negatively regulates basal p65 NF-kappaB activity. J Biol Chem 2004; 279:49571-4. [PMID: 15465828 DOI: 10.1074/jbc.c400442200] [Citation(s) in RCA: 200] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The activity of NF-kappaB is controlled at several levels including the phosphorylation of the strongly transactivating p65 (RelA) subunit. However, the overall number of phosphorylation sites, the signaling pathways and protein kinases that target p65 NF-kappaB and the functional role of these phosphorylations are still being uncovered. Using a combination of peptide arrays with in vitro kinase assays we identify serine 468 as a novel phosphorylation site of p65 NF-kappaB. Serine 468 lies within a GSK-3beta consensus site, and recombinant GSK-3beta specifically phosphorylates a GST-p65-(354-551) fusion protein at Ser(468) in vitro. In intact cells, phosphorylation of endogenous Ser(468) of p65 is induced by the PP1/PP2A phosphatase inhibitor calyculin A and this effect is inhibited by the GSK-3beta inhibitor LiCl. Reconstitution of p65-deficient cells with a p65 protein where serine 468 was mutated to alanine revealed a negative regulatory role of serine 468 for NF-kappaB activation. Collectively our results suggest that a GSK-3beta-PP1-dependent mechanism regulates phosphorylation of p65 NF-kappaB at Ser(468) in unstimulated cells and thereby controls the basal activity of NF-kappaB.
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Affiliation(s)
- Holger Buss
- Institute of Pharmacology, Medical School Hannover, Carl-Neuberg Strasse 1, D-30625 Hannover, Germany
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230
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Wu W, Mosteller RD, Broek D. Sphingosine kinase protects lipopolysaccharide-activated macrophages from apoptosis. Mol Cell Biol 2004; 24:7359-69. [PMID: 15314148 PMCID: PMC507005 DOI: 10.1128/mcb.24.17.7359-7369.2004] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lipopolysaccharide (LPS) signaling is critical for the innate immune response to gram-negative bacteria. Here, evidence is presented for LPS stimulation of sphingosine kinase (SPK) in the RAW 264.7 murine macrophage cell line and rat primary hepatic macrophages (HMs). LPS treatment of RAW 264.7 cells resulted in a time- and dose-dependent activation of SPK and membrane translocation of SPK1. Further, LPS-induced SPK activation was blocked by SPK1-specific small interfering RNA (siRNA). Overexpression of Toll-like receptor 4 and MD2, the receptor and coreceptor of LPS, in HEK 293 cells activated SPK activity in the absence of LPS treatment. Inhibition of SPK by the pharmacological inhibitor N,N-dimethylsphingosine (DMS) or SPK1-specific siRNA blocked LPS stimulation of extracellular signal-regulated kinase 1/2 and p38 but enhanced LPS-induced c-Jun N-terminal kinase activation. The SPK inhibitor DMS and dominant-negative SPK1 also blocked LPS activation of Elk-1 and NF-kappaB reporters in RAW 264.7 cells. Inhibition of SPK sensitized RAW 264.7 cells and HMs to LPS-induced apoptosis. These data demonstrate the critical role of SPK1 in LPS signaling in macrophages and suggest that SPK1 is a potential therapeutic target to block hyperimmune responses induced by gram-negative bacteria.
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Affiliation(s)
- Weicheng Wu
- Department of Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, Keck School of Medicine at the University of Southern California, Los Angeles 90089, USA
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231
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Soloff RS, Katayama C, Lin MY, Feramisco JR, Hedrick SM. Targeted deletion of protein kinase C lambda reveals a distribution of functions between the two atypical protein kinase C isoforms. THE JOURNAL OF IMMUNOLOGY 2004; 173:3250-60. [PMID: 15322187 DOI: 10.4049/jimmunol.173.5.3250] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Protein kinase C lambda (PKClambda) is an atypical member of the PKC family of serine/threonine kinases with high similarity to the other atypical family member, PKCzeta. This similarity has made it difficult to determine specific roles for the individual atypical isoforms. Both PKClambda and PKCzeta have been implicated in the signal transduction, initiated by mediators of innate immunity, that culminates in the activation of MAPKs and NF-kappaB. In addition, work from invertebrates shows that atypical PKC molecules play a role in embryo development and cell polarity. To determine the unique functions of PKClambda, mice deficient for PKClambda were generated by gene targeting. The ablation of PKClambda results in abnormalities early in gestation with lethality occurring by embryonic day 9. The role of PKClambda in cytokine-mediated cellular activation was studied by making mouse chimeras from PKClambda-deficient embryonic stem cells and C57BL/6 or Rag2-deficient blastocysts. Cell lines derived from these chimeric animals were then used to dissect the role of PKClambda in cytokine responses. Although the mutant cells exhibited alterations in actin stress fibers and focal adhesions, no other phenotypic differences were noted. Contrary to experiments using dominant interfering forms of PKClambda, mutant cells responded normally to TNF, serum, epidermal growth factor, IL-1, and LPS. In addition, no abnormalities were found in T cell development or T cell activation. These data establish that, in vertebrates, the two disparate functions of atypical PKC molecules have been segregated such that PKCzeta mediates signal transduction of the innate immune system and PKClambda is essential for early embryogenesis.
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Affiliation(s)
- Rachel S Soloff
- Division of Biological Sciences, Moores University of California at San Diego Cancer Center, La Jolla 92093, USA
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232
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Cuschieri J, Umanskiy K, Solomkin J. PKC-ζ is essential for endotoxin-induced macrophage activation1,2. J Surg Res 2004; 121:76-83. [PMID: 15313379 DOI: 10.1016/j.jss.2004.04.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2003] [Indexed: 11/15/2022]
Abstract
BACKGROUND A critical element in sepsis-induced tissue injury is the release of pro-inflammatory mediators from LPS-activated macrophages. The cellular mechanisms involved in this process remain incompletely understood. The aim of the current study was to further clarify the mechanism of LPS activation through the TLR4 receptor complex by examining the roles of the various isoforms of PKC. MATERIALS AND METHODS Differentiated THP-1 cells were subjected to LPS stimulation. Selected cells were pretreated with various concentrations of Gö6983 to inhibit conventional, novel, and atypical PKC isoforms. Lipid raft, cellular, and nuclear proteins were then extracted and analyzed by Western blot and EMSA for components of the TLR4 pathway. Supernatants harvested under the various conditions were analyzed by ELISA for the production of TNF-alpha. RESULTS LPS stimulation led to the mobilization of TLR4 to lipid rafts followed by phosphorylation and activation of IRAK, ERK 1/2, p38, and JNK/SAPK. Subsequently, LPS induced the activation of NF-kappaB and AP-1. Activation of these TLR4-signaling components resulted in the production of TNF-alpha. Inhibition of conventional and novel PKC isoforms had no significant effect on macrophage activation. Inhibition of the atypical PKC, PKC-zeta, was associated with significant attenuation in the mobilization of TLR4 to lipid rafts, the activation of all TLR4-signaling components, and the production of TNF-alpha. CONCLUSION This study demonstrates that the atypical PKC isoform, PKC-zeta, is critical to regulation of LPS-induced TLR4 lipid raft mobilization within macrophages, TLR4-signaling, and TNF-alpha production. Although the mechanism of its activation remains unresolved, it appears that modulation of PKC-zeta activity during Gram-negative infections may limit associated inflammatory-induced morbidity.
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Affiliation(s)
- Joseph Cuschieri
- Department of Surgery, University of Cincinnati, 231 Albert Sabin Way, ML 558, Cincinnati, OH 45267-0558, USA
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233
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Cummings R, Zhao Y, Jacoby D, Spannhake EW, Ohba M, Garcia JGN, Watkins T, He D, Saatian B, Natarajan V. Protein Kinase Cδ Mediates Lysophosphatidic Acid-induced NF-κB Activation and Interleukin-8 Secretion in Human Bronchial Epithelial Cells. J Biol Chem 2004; 279:41085-94. [PMID: 15280372 DOI: 10.1074/jbc.m404045200] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Lysophosphatidic acid (LPA), a potent bioactive lipid, elicits many of its biological actions via the specific G-protein-coupled receptors LPA1, LPA2, LPA3, and LPA4. Recently, we have shown that LPA-induced transactivation of platelet-derived growth factor receptor-beta is regulated by phospholipase D2 in human bronchial epithelial cells (HBEpCs) (Wang, L., Cummings, R. J., Zhao, Y., Kazlauskas, A., Sham, J., Morris, A., Brindley, D. N., Georas, S., and Natarajan, V. (2003) J. Biol. Chem. 278, 39931-39940). Here, we report that protein kinase Cdelta (PKCdelta) mediates LPA-induced NF-kappaB transcription and interleukin-8 (IL-8) secretion in HBEpCs. Treatment of HBEpCs with LPA increased both IL-8 gene and protein expression, which was coupled to Gi and G(12/13) proteins. LPA caused a marked activation of NF-kappaB in HBEpCs as determined by IkappaB phosphorylation and of NF-kappaB nuclear translocation and a strong induction of NF-kappaB promoter-mediated luciferase activity. Furthermore, LPA-activated PKCdelta and the LPA-mediated activation of NF-kappaB and IL-8 production were attenuated by overexpression of dominant-negative PKCdelta and rottlerin. Intratracheal administration of LPA in mice resulted in elevated levels of macrophage inflammatory protein-2, a murine homolog of IL-8, and an influx of neutrophils in the bronchoalveolar lavage fluid. These results demonstrate for the first time that LPA is a potent stimulator of IL-8 production in HBEpCs, which involves PKCdelta/NF-kappaB signaling pathways.
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Affiliation(s)
- Rhett Cummings
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21224, USA
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234
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Teusch N, Lombardo E, Eddleston J, Knaus UG. The low molecular weight GTPase RhoA and atypical protein kinase Czeta are required for TLR2-mediated gene transcription. THE JOURNAL OF IMMUNOLOGY 2004; 173:507-14. [PMID: 15210811 DOI: 10.4049/jimmunol.173.1.507] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The Rho GTPases are molecular switches that regulate many essential cellular processes, including actin dynamics, gene transcription, cell cycle progression, cell adhesion, and motility. In this study, we report that stimulation of TLR2 in human epithelial and monocytic cells leads to rapid and transient activation of RhoA. RhoA cooperated with the canonical I-kappaB kinase-mediated pathway that induces the release of NF-kappaB, in regulating the trans activation of the NF-kappaB subunit p65/RelA by affecting Ser(311) phosphorylation, and subsequent cytokine production. Another consequence of TLR2 stimulation by bacterial derived products was the activation of atypical protein kinase C (PKC) zeta and association of this protein kinase with RhoA. Inhibition of PKCzeta decreased NF-kappaB activation and p65/RelA trans activation without affecting I-kappaBalpha degradation. The observation of a transient, stimulus-dependent association of RhoA with PKCzeta suggests that RhoA mediates at least partially its effect on gene transcription through atypical PKC. In contrast to previous studies, identifying Rac1-PI3K as an upstream element in TLR2-initiated response to NF-kappaB, PI3K signaling was not required for RhoA or PKCzeta activity. These results indicate that multiple GTPase-regulated pathways emerge from stimulated Toll receptors, controlling different aspects of NF-kappaB-mediated gene transcription.
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Affiliation(s)
- Nicole Teusch
- Department of Immunology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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235
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Sotillos S, Díaz-Meco MT, Caminero E, Moscat J, Campuzano S. DaPKC-dependent phosphorylation of Crumbs is required for epithelial cell polarity in Drosophila. ACTA ACUST UNITED AC 2004; 166:549-57. [PMID: 15302858 PMCID: PMC2172211 DOI: 10.1083/jcb.200311031] [Citation(s) in RCA: 194] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Both in Drosophila and vertebrate epithelial cells, the establishment of apicobasal polarity requires the apically localized, membrane-associated Par-3–Par-6–aPKC protein complex. In Drosophila, this complex colocalizes with the Crumbs–Stardust (Sdt)–Pals1-associated TJ protein (Patj) complex. Genetic and molecular analyses suggest a functional relationship between them. We show, by overexpression of a kinase-dead Drosophila atypical PKC (DaPKC), the requirement for the kinase activity of DaPKC to maintain the position of apical determinants and to restrict the localization of basolateral ones. We demonstrate a novel physical interaction between the apical complexes, via direct binding of DaPKC to both Crb and Patj, and identify Crumbs as a phosphorylation target of DaPKC. This phosphorylation of Crumbs is functionally significant. Thus, a nonphosphorylatable Crumbs protein behaves in vivo as a dominant negative. Moreover, the phenotypic effect of overexpressing wild-type Crumbs is suppressed by reducing DaPKC activity. These results provide a mechanistic framework for the functional interaction between the Par-3–Par-6–aPKC and Crumbs–Sdt–Patj complexes based in the posttranslational modification of Crb by DaPKC.
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Affiliation(s)
- Sol Sotillos
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Cientificas and Univerisidad Autonoma de Madrid, Cantoblanco, 28049 Madrid, Spain
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236
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Oster H, Eichele G, Leitges M. Differential expression of atypical PKCs in the adult mouse brain. ACTA ACUST UNITED AC 2004; 127:79-88. [PMID: 15306123 DOI: 10.1016/j.molbrainres.2004.05.009] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/03/2004] [Indexed: 11/21/2022]
Abstract
The protein kinase C (PKC) family of serine/threonine kinases plays a role in a variety of physiological and pathophysiological processes in the brain including development, synaptic plasticity, epilepsy, ischemia, and neuronal cell death. The subgroup of atypical PKCs (aPKCs) comprises of three members, PKCiota/lambda, PKCzeta, and PKMzeta, with high amino acid homology. We used specific RNA probes and in situ hybridization to determine the expression patterns of all the three isoforms in the adult mouse brain. PKCiota and PKMzeta were found to be broadly expressed in most of the cortex, the limbic system, and the thalamus. In contrast, PKCzeta transcription was restricted to distinct forebrain areas and the cerebellum. Here we present a first comprehensive overview of isotype-specific aPKC distribution in the central nervous system, thereby providing a solid ground for further studies on the functional implications of the different aPKCs in the neuronal system.
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Affiliation(s)
- Henrik Oster
- Laboratories for Chronobiology and Signal Transduction, Max Planck Institute of Experimental Endocrinology, Feodor Lynen Str. 7, 30625 Hannover, Germany.
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237
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Kraus M, Alimzhanov MB, Rajewsky N, Rajewsky K. Survival of resting mature B lymphocytes depends on BCR signaling via the Igalpha/beta heterodimer. Cell 2004; 117:787-800. [PMID: 15186779 DOI: 10.1016/j.cell.2004.05.014] [Citation(s) in RCA: 444] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2004] [Revised: 04/08/2004] [Accepted: 04/12/2004] [Indexed: 12/19/2022]
Abstract
We previously showed that type I interferon-induced, Cre-mediated ablation of surface BCR expression in mature B cells through Ig-heavy chain deletion results in apoptosis of these cells. This led to the hypothesis that survival signals from the BCR are vital for mature B cells. Here, we test two critical assumptions of this model. First, we demonstrate loss of mature B cells upon induced mutation of a signaling module of the BCR, not precluding BCR surface expression. Second, we show that the cells are also lost upon BCR inactivation in the absence of an exogenous inducer like interferon, excluding that cell death depends on previous cellular activation by the latter. Kinetic data demonstrate that BCR-less mature B cells have a severely reduced lifespan, with a half-life of 3-6 days. Together these results establish that BCR signaling is required to keep resting mature B cells alive in vivo.
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Affiliation(s)
- Manfred Kraus
- New York University, Department of Biology, 1009 Main Building, 100 Washington Square East, New York, NY 10003, USA
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238
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Storz P, Döppler H, Toker A. Activation loop phosphorylation controls protein kinase D-dependent activation of nuclear factor kappaB. Mol Pharmacol 2004; 66:870-9. [PMID: 15226414 DOI: 10.1124/mol.104.000687] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Activation of the inducible transcription factor nuclear factor kappaB (NF-kappaB) occurs in cells exposed to oxidative stress, and the serine/threonine kinase protein kinase D (PKD) is critical for signal relay to NF-kappaB. We have recently delineated two coordinated events that control PKD activation in response to oxidative stress: phosphorylation at Tyr463 by the tyrosine kinase Abl, and phosphorylation at the activation loop Ser738/Ser742 by the protein kinase C (PKC) isoform PKCdelta. The result is fully active PKD that controls NF-kappaB activation through the IkappaB kinase (IKK) complex. Here, we investigate the mechanism by which PKD controls IKK/NF-kappaB activation. Resveratrol, a potent antioxidant, blocks both PKD activation and NF-kappaB induction. In particular, resveratrol blocked PKD activation loop phosphorylation and activity, and this was caused by a specific inhibition of the Ser738/Ser742 kinase PKCdelta. On the other hand, resveratrol did not affect Abl kinase activity and had no effect on Tyr463 phosphorylation. Moreover, we show that the mechanism by which resveratrol inhibits NF-kappaB is by blocking the translocation of PKD to the IKK complex, specifically by inhibiting Ser738/Ser742 phosphorylation. We therefore propose that rather than acting as an antioxidant, resveratrol specifically blocks oxidative stress-dependent NF-kappaB activation by interfering with PKD phosphorylation and association with the IKK complex.
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Affiliation(s)
- Peter Storz
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA
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239
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Abstract
Members of the protein kinase C (PKC) family play important but distinct roles in B-cell activation, as demonstrated by emerging genetic and biochemical studies. PKCbeta is indispensable for B-cell antigen receptor (BCR)-induced NF-kappaB activation and B-cell survival. Recent evidence indicates that PKCbeta might regulate inhibitor of kappaB kinase (IKK) and NF-kappaB activation through interaction with the CARMA1/Bcl10/MALT signaling complex in BCR microdomains. By contrast, the novel PKC isoform PKCdelta is specifically required to maintain the tolerance of self-reactive B cells.
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Affiliation(s)
- Beichu Guo
- Department of Immunology, University of Washington School of Medicine, Seattle 98195, USA
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240
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Weil R, Israël A. T-cell-receptor- and B-cell-receptor-mediated activation of NF-κB in lymphocytes. Curr Opin Immunol 2004; 16:374-81. [PMID: 15134788 DOI: 10.1016/j.coi.2004.03.003] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
B and T cells sense antigens through specific receptors, which, when activated, induce signalling cascades leading to the activation of a series of transcription factor families, such as NF-kappaB. These transcription factors control differentiation, cytokine production and proliferation, and they protect against apoptosis. Much progress has been made during the past two years in the understanding of the molecular events leading to NF-kappaB activation, but, although most of the molecules in this signalling cascade have now been identified, the detailed molecular events remain obscure; in particular regarding the molecules that specifically connect the T-cell receptor (TCR)- and B-cell receptor (BCR)-proximal adaptors and kinases to the central core of the NF-kappaB cascade, the IkappaB kinase complex. As these events are likely to be specific for both extremities of the signalling cascade (the TCR or BCR on one end, and NF-kappaB target genes on the other) they will ultimately represent the best targets to specifically manipulate this response in lymphocytes.
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Affiliation(s)
- Robert Weil
- Unité de Biologie Moléculaire de l'Expression Génique, Unité de Recherche Associée, 2582 Centre National de la Recherche Scientifique, Institut Pasteur, 25 Rue du Dr. Roux, 75724 Paris Cedex 15, France
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241
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Affiliation(s)
- Lin-Feng Chen
- Gladstone Institute of Virology and Immunology, University of California, San Francisco, California 94141, USA
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242
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Marchetti L, Klein M, Schlett K, Pfizenmaier K, Eisel ULM. Tumor necrosis factor (TNF)-mediated neuroprotection against glutamate-induced excitotoxicity is enhanced by N-methyl-D-aspartate receptor activation. Essential role of a TNF receptor 2-mediated phosphatidylinositol 3-kinase-dependent NF-kappa B pathway. J Biol Chem 2004; 279:32869-81. [PMID: 15155767 DOI: 10.1074/jbc.m311766200] [Citation(s) in RCA: 312] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
We have previously shown that two tumor necrosis factor (TNF) receptors (TNFR) exhibit antagonistic functions during neurodegenerative processes in vivo with TNFR1 aggravating and TNFR2 reducing neuronal cell loss, respectively. To elucidate the neuroprotective signaling pathways of TNFR2, we investigated glutamate-induced excitotoxicity in primary cortical neurons. TNF-expressing neurons from TNF-transgenic mice were found to be strongly protected from glutamate-induced apoptosis. Neurons from wild type and TNFR1(-/-) mice prestimulated with TNF or agonistic TNFR2-specific antibodies were also resistant to excitotoxicity, whereas TNFR2(-/-) neurons died upon glutamate and/or TNF exposures. Both protein kinase B/Akt and nuclear factor-kappa B (NF-kappa B) activation were apparent upon TNF treatment. Both TNFR1 and TNFR2 induced the NF-kappa B pathway, yet with distinguishable kinetics and upstream activating components, TNFR1 only induced transient NF-kappa B activation, whereas TNFR2 facilitated long term phosphatidylinositol 3-kinase-dependent NF-kappa B activation strictly. Glutamate-induced triggering of the ionotropic N-methyl-D-aspartate receptor was required for the enhanced and persistent phosphatidylinositol 3-kinase-dependent NF-kappa B activation by TNFR2, indicating a positive cooperation of TNF and neurotransmitter-induced signal pathways. TNFR2-induced persistent NF-kappa B activity was essential for neuronal survival. Thus, the duration of NF-kappa B activation is a critical determinant for sensitivity toward excitotoxic stress and is dependent on a differential upstream signal pathway usage of the two TNFRs.
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MESH Headings
- Animals
- Antigens, CD/metabolism
- Apoptosis
- Blotting, Northern
- Blotting, Western
- Brain/metabolism
- Cell Death
- Cell Nucleus/metabolism
- Cell Survival
- Cells, Cultured
- Dose-Response Relationship, Drug
- Enzyme Activation
- Glutamates/metabolism
- Glutamic Acid/metabolism
- Immunohistochemistry
- Kinetics
- Mice
- Mice, Transgenic
- Models, Genetic
- NF-kappa B/metabolism
- Neurons/metabolism
- Phosphatidylinositol 3-Kinases/metabolism
- Protein Serine-Threonine Kinases/metabolism
- Proto-Oncogene Proteins/metabolism
- Proto-Oncogene Proteins c-akt
- Receptors, N-Methyl-D-Aspartate/metabolism
- Receptors, Tumor Necrosis Factor/metabolism
- Receptors, Tumor Necrosis Factor, Type II
- Signal Transduction
- Time Factors
- Tumor Necrosis Factor-alpha/metabolism
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Affiliation(s)
- Lara Marchetti
- Institute of Cell Biology and Immunology, University of Stuttgart, Allmandring 31, D-70569 Stuttgart, Germany
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243
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Storz P, Döppler H, Toker A. Protein kinase Cdelta selectively regulates protein kinase D-dependent activation of NF-kappaB in oxidative stress signaling. Mol Cell Biol 2004; 24:2614-26. [PMID: 15024053 PMCID: PMC371115 DOI: 10.1128/mcb.24.7.2614-2626.2004] [Citation(s) in RCA: 188] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Protein kinase D (PKD) participates in activation of the transcription factor NF-kappaB (nuclear factor kappaB) in cells exposed to oxidative stress, leading to increased cellular survival. We previously demonstrated that phosphorylation of PKD at Tyr463 in the PH (pleckstrin homology) domain is mediated by the Src-Abl pathway and that it is necessary for PKD activation and subsequent NF-kappaB induction. Here we show that activation of PKD in response to oxidative stress requires two sequential signaling events, i.e., phosphorylation of Tyr463 by Abl, which in turn promotes a second step, phosphorylation of the PKD activation loop (Ser738/Ser742). We show that this is mediated by PKCdelta (protein kinase Cdelta), a kinase that is activated by Src in response to oxidative stress. We also show that other PKCs, including PKCepsilon and PKCzeta, do not participate in PKD activation or NF-kappaB induction. We propose a model in which two coordinated signaling events are required for PKD activation. Tyrosine phosphorylation in the PH domain at Tyr463, mediated by the Src-Abl pathway, which in turn facilitates the phosphorylation of Ser738/Ser742 in the activation loop, mediated by the Src-PKCdelta pathway. Once active, the signal is relayed to the activation of NF-kappaB in oxidative stress responses.
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Affiliation(s)
- Peter Storz
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA
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244
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Reynolds CP, Maurer BJ, Kolesnick RN. Ceramide synthesis and metabolism as a target for cancer therapy. Cancer Lett 2004; 206:169-80. [PMID: 15013522 DOI: 10.1016/j.canlet.2003.08.034] [Citation(s) in RCA: 260] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2003] [Accepted: 08/14/2003] [Indexed: 12/29/2022]
Abstract
Sphingolipids, which include ceramides and sphingosine, are essential structural components of cell membranes that also have messenger functions that regulate the proliferation, survival, and death of cells. Exogenous application of ceramide is cytotoxic, and exposure of cells to radiation or chemotherapy is associated with increased ceramide levels due to enhanced de novo synthesis, catabolism of sphingomyelin, or both. Ceramide can be metabolized to less toxic forms by glycosylation, acylation, or by catabolism to sphingosine, which is then phosphorylated to the anti-apoptotic sphingosine 1-phosphate. Glucosylceramide synthase overexpression has been shown to enhance resistance to doxorubicin, suggesting that inhibition of ceramide metabolism or catabolism might enhance cancer chemotherapy. Several anticancer agents, including the cytotoxic retinoid, fenretinide (4-HPR), have been shown to act, at least in part, by increasing tumor cell ceramide via de novo synthesis. Combinations of 4-HPR and modulators of ceramide action and/or metabolism demonstrated increased anti-tumor activity in pre-clinical models with minimal toxicity for non-malignant cells, and were effective in a p53-independent manner against tumor cell lines resistant to standard cytotoxic agents. Phase I trials of ceramide metabolism inhibitors in combination with 4-HPR and with other cytotoxic agents are in development. Thus, pharmacological manipulation of sphingolipid metabolism to enhance tumor cell ceramide is being realized and offers a novel approach to cancer chemotherapy.
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Affiliation(s)
- C Patrick Reynolds
- Division of Hematology-Oncology MS 57, Children's Hospital of Los Angeles, The University of Southern California Keck School of Medicine, 4650 Sunset Blvd., Los Angeles, CA 90054-0700, USA.
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245
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Wajant H, Scheurich P. Analogies between Drosophila and mammalian TRAF pathways. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2004; 34:47-72. [PMID: 14979664 DOI: 10.1007/978-3-642-18670-7_3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A central event in innate immunity is the activation of the NF-kappaB signaling pathway and up-regulation of NF-kappaB-dependent defense genes. Attack of mammals as well as of insects by microorganisms leads, among other things, to the activation of receptors of the Toll-like receptor group. Various adaptor proteins involving members of the TNF receptor-associated factor (TRAF) family channel these receptor-generated signals to conserved intracellular kinase cascades that finally lead to the activation of NF-kappaB and JNK. In vertebrates, TRAF proteins link these pathways also to IL-1R-related molecules and members of the TNF receptor superfamily, which orchestrate a variety of immunoregulatory processes of the innate but also of the adaptive immune system. In this review, we will focus on the similarities but also the differences in TRAF-dependent signaling pathways of mammals and insects.
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Affiliation(s)
- H Wajant
- Department of Molecular Internal Medicine, Medical Polyclinic, University Würzburg, Röntgenring 11, 97070 Würzburg, Germany
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246
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Hinton HJ, Alessi DR, Cantrell DA. The serine kinase phosphoinositide-dependent kinase 1 (PDK1) regulates T cell development. Nat Immunol 2004; 5:539-45. [PMID: 15077109 DOI: 10.1038/ni1062] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2003] [Accepted: 02/18/2004] [Indexed: 12/24/2022]
Abstract
T lymphocyte activation is associated with activation of diverse AGC serine kinases (named after family members protein kinase A, protein kinase G and protein kinase C). It has been difficult to assess the function of these molecules in T cell development with simple gene-deletion strategies because different isoforms of AGC kinases are coexpressed in the thymus and have overlapping, redundant functions. To circumvent these problems, we explored the consequences of genetic manipulation of phosphoinositide-dependent kinase 1 (PDK1), a rate-limiting 'upstream' activator of AGC kinases. Here we analyzed the effect of PDK1 deletion on T lineage development. We also assessed the consequences of reducing PDK1 levels to 10% of normal. Complete PDK1 loss blocked T cell differentiation in the thymus, whereas reduced PDK1 expression allowed T cell differentiation but blocked proliferative expansion. These studies show that AGC family kinases are essential for T cell development.
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Affiliation(s)
- Heather J Hinton
- Lymphocyte Activation Laboratory, Cancer Research UK London Research Institute, Lincoln's Inn Fields, London WC2A 3PX, United Kingdom
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247
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Watson RT, Kanzaki M, Pessin JE. Regulated membrane trafficking of the insulin-responsive glucose transporter 4 in adipocytes. Endocr Rev 2004; 25:177-204. [PMID: 15082519 DOI: 10.1210/er.2003-0011] [Citation(s) in RCA: 309] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Since the discovery of insulin roughly 80 yr ago, much has been learned about how target cells receive, interpret, and respond to this peptide hormone. For example, we now know that insulin activates the tyrosine kinase activity of its cell surface receptor, thereby triggering intracellular signaling cascades that regulate many cellular processes. With respect to glucose homeostasis, these include the function of insulin to suppress hepatic glucose production and to increase glucose uptake in muscle and adipose tissues, the latter resulting from the translocation of the glucose transporter 4 (GLUT4) to the cell surface membrane. Although simple in broad outline, elucidating the molecular intricacies of these receptor-signaling pathways and membrane-trafficking processes continues to challenge the creative ingenuity of scientists, and many questions remain unresolved, or even perhaps unasked. The identification and functional characterization of specific molecules required for both insulin signaling and GLUT4 vesicle trafficking remain key issues in our pursuit of developing specific therapeutic agents to treat and/or prevent this debilitating disease process. To this end, the combined efforts of numerous research groups employing a range of experimental approaches has led to a clearer molecular picture of how insulin regulates the membrane trafficking of GLUT4.
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Affiliation(s)
- Robert T Watson
- Department of Pharmacological Sciences, State University of New York at Stony Brook, Stony Brook, NY 11794, USA
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248
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Hong CY, Park JH, Ahn RS, Im SY, Choi HS, Soh J, Mellon SH, Lee K. Molecular mechanism of suppression of testicular steroidogenesis by proinflammatory cytokine tumor necrosis factor alpha. Mol Cell Biol 2004; 24:2593-604. [PMID: 15024051 PMCID: PMC371106 DOI: 10.1128/mcb.24.7.2593-2604.2004] [Citation(s) in RCA: 216] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2003] [Revised: 09/23/2003] [Accepted: 12/29/2003] [Indexed: 11/20/2022] Open
Abstract
Tumor necrosis factor alpha (TNF-alpha) has been demonstrated to inhibit steroidogenesis in Leydig cells at the transcriptional level of steroidogenic enzymes. However, the molecular mechanism of this observed gene repression is not well understood. We now demonstrate that nuclear factor kappaB (NF-kappaB) activated by TNF-alpha inhibits the transactivation of orphan nuclear receptors, which regulate the expression of steroidogenic-enzyme genes. TNF-alpha treatment suppressed the luteinizing-hormone-induced or Nur77/SF-1-stimulated promoter activity of steroidogenic-enzyme genes in Leydig cells. The TNF-alpha-mediated gene suppression was blocked by treatment with an inhibitor of NF-kappaB. In addition, overexpression of the p65 (RelA) subunit of NF-kappaB showed the same effect as TNF-alpha and inhibited Nur77 transactivation, suggesting the involvement of NF-kappaB activation in the observed gene repression. Physical association of Nur77 with p65 was revealed by mammalian two-hybrid, GST pull-down, and coimmunoprecipitation analyses. The NF-kappaB inhibition of Nur77 transactivation was likely due to the competition of p65 for Nur77 binding with coactivators. Finally, chromatin immunoprecipitation assays revealed that TNF-alpha treatment caused the recruitment of NF-kappaB to the promoter of the steroidogenic-enzyme p450c17 gene, supporting the hypothesis that the TNF-alpha-mediated gene repression involves NF-kappaB inhibition of the transcriptional activity of Nur77 and other orphan nuclear receptors. These findings provide a molecular mechanism underlying the inhibition of testicular steroidogenesis by proinflammatory cytokines.
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Affiliation(s)
- Cheol Yi Hong
- Hormone Research Center, School of Biological Sciences and Technology, Department of Biology, Chonnam National University, Gwangju 500-757, Republic of Korea
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Durán A, Serrano M, Leitges M, Flores JM, Picard S, Brown JP, Moscat J, Diaz-Meco MT. The atypical PKC-interacting protein p62 is an important mediator of RANK-activated osteoclastogenesis. Dev Cell 2004; 6:303-9. [PMID: 14960283 DOI: 10.1016/s1534-5807(03)00403-9] [Citation(s) in RCA: 259] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2003] [Revised: 12/04/2003] [Accepted: 12/11/2003] [Indexed: 11/16/2022]
Abstract
The atypical PKCs (aPKCs) have been implicated genetically in at least two independent signaling cascades that control NF-kappa B and cell polarity, through the interaction with the adapters p62 and Par-6, respectively. P62 binds TRAF6, which plays an essential role in osteoclastogenesis and bone remodeling. Recently, p62 mutations have been shown to be the cause of the 5q35-linked Paget's disease of bone, a genetic disorder characterized by aberrant osteoclastic activity. Here we show that p62, like TRAF6, is upregulated during RANK-L-induced osteoclastogenesis and that the genetic inactivation of p62 in mice leads to impaired osteoclastogenesis in vitro and in vivo, as well as inhibition of IKK activation and NF-kappa B nuclear translocation. In addition, RANK-L stimulation leads to the inducible formation of a ternary complex involving TRAF6, p62, and the aPKCs. These observations demonstrate that p62 is an important mediator during osteoclastogenesis and induced bone remodeling.
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Affiliation(s)
- Angeles Durán
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma, Canto Blanco, 28049 Madrid, Spain
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Sclabas GM, Fujioka S, Schmidt C, Evans DB, Chiao PJ. NF-kappaB in pancreatic cancer. INTERNATIONAL JOURNAL OF GASTROINTESTINAL CANCER 2004; 33:15-26. [PMID: 12909735 DOI: 10.1385/ijgc:33:1:15] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Although the genetic profile of pancreatic cancer is emerging as a result of much research, the role of specific genetic alterations that initiate tumorigenesis and produce its cardinal clinical features of locally aggressive growth, metastasis, and chemotherapy resistance remains unresolved. Recently, a number of studies have shown that the inhibition of constitutive NF-kappaB activation, one of the frequent molecular alterations in pancreatic cancer, inhibits tumorigenesis and metastasis. It also sensitizes pancreatic cancer cell lines to anticancer agent-induced apoptosis. Therefore because of the crucial role of NF-kappaB in pancreatic cancer, it is a potential target for developing novel therapeutic strategies for the disease. In vivo and in vitro models that mimic the tumorigenic phenotypes in the appropriate histological and molecular concert would be very useful for confirming the suspected role of the pancreatic cancer signature genetic lesions and better understanding the molecular basis of this disease.
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Affiliation(s)
- Guido M Sclabas
- Department of Surgical Oncology, The University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030, USA
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