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1.
J Gen Intern Med ; 34(3): 379-386, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30543021

RESUMO

BACKGROUND: Current treatment options for knee osteoarthritis have limited effectiveness and potentially adverse side effects. Massage may offer a safe and effective complement to the management of knee osteoarthritis. OBJECTIVE: Examine effects of whole-body massage on knee osteoarthritis, compared to active control (light-touch) and usual care. DESIGN: Multisite RCT assessing the efficacy of massage compared to light-touch and usual care in adults with knee osteoarthritis, with assessments at baseline and weeks 8, 16, 24, 36, and 52. Subjects in massage or light-touch groups received eight weekly treatments, then were randomized to biweekly intervention or usual care to week 52. The original usual care group continued to week 24. Analysis was performed on an intention-to-treat basis. PARTICIPANTS: Five hundred fifty-one screened for eligibility, 222 adults with knee osteoarthritis enrolled, 200 completed 8-week assessments, and 175 completed 52-week assessments. INTERVENTION: Sixty minutes of protocolized full-body massage or light-touch. MAIN MEASURES: Primary: Western Ontario and McMaster Universities Arthritis Index. Secondary: visual analog pain scale, PROMIS Pain Interference, knee range of motion, and timed 50-ft walk. KEY RESULTS: At 8 weeks, massage significantly improved WOMAC Global scores compared to light-touch (- 8.16, 95% CI = - 13.50 to - 2.81) and usual care (- 9.55, 95% CI = - 14.66 to - 4.45). Additionally, massage improved pain, stiffness, and physical function WOMAC subscale scores compared to light-touch (p < 0.001; p = 0.04; p = 0.02, respectively) and usual care (p < 0.001; p = 0.002; p = 0.002; respectively). At 52 weeks, the omnibus test of any group difference in the change in WOMAC Global from baseline to 52 weeks was not significant (p = 0.707, df = 3), indicating no significant difference in change across groups. Adverse events were minimal. CONCLUSIONS: Efficacy of symptom relief and safety of weekly massage make it an attractive short-term treatment option for knee osteoarthritis. Longer-term biweekly dose maintained improvement, but did not provide additional benefit beyond usual care post 8-week treatment. TRIAL REGISTRATION: clinicaltrials.gov NCT01537484.


Assuntos
Massagem/métodos , Osteoartrite do Joelho/diagnóstico , Osteoartrite do Joelho/terapia , Medição da Dor/métodos , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento
2.
Am J Prev Med ; 49(5 Suppl 3): S257-62, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26477901

RESUMO

Integrative medicine training was incorporated into the Rutgers New Jersey Medical School Preventive Medicine residency at the Rutgers Biomedical and Health Sciences Newark Campus as a collaboration between the Rutgers New Jersey Medical School and the School of Health Related Professions. Beginning in 2012, an interdisciplinary faculty team organized an Integrative Medicine program in a Preventive Medicine residency that leveraged existing resources across Rutgers Biomedical and Health Sciences. The overarching aim of the programs was to introduce residents and faculty to the scope and practice of integrative medicine in the surrounding Newark community and explore evidence-based research on integrative medicine. The faculty team tapped into an interprofessional network of healthcare providers to organize rotations for the preventive medicine residents that reflected the unique nature of integrative medicine in the greater Newark area. Residents provided direct care as part of interdisciplinary teams at clinical affiliates and shadowed health professionals from diverse disciplines as they filled different roles in providing patient care. The residents also participated in research projects. A combination of formal and informal programs on integrative medicine topics was offered to residents and faculty. The Integrative Medicine program, which ran from 2013 through 2014, was successful in exposing residents and faculty to the unique nature of integrative medicine across professions in the community served by Rutgers Biomedical and Health Sciences.


Assuntos
Currículo/normas , Medicina Integrativa/educação , Internato e Residência/normas , Comportamento Cooperativo , Humanos , Medicina Integrativa/normas , New Jersey , Avaliação de Programas e Projetos de Saúde
3.
Blood ; 122(12): 2114-24, 2013 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-23950177

RESUMO

We have identified a ubiquitin-binding domain within the NH2-terminal sequences of p210 BCR/ABL and determined that the binding site co-localizes with the binding site for ß-catenin. The domain does not support the auto- or trans-kinase activity of p210 BCR/ABL or its ability to interact with GRB2 and activate ERK1/2 signaling. Expression of p210 BCR/ABL, but not a ß-catenin-binding mutant, in hematopoietic cells is associated with the accumulation of p-ß-catenin (Tyr654) and increased TCF/LEF-mediated transcription. In a bone marrow transplantation model, the interaction between ß-catenin and p-ß-catenin (Tyr654) is detectable in mice transplanted with p210 BCR/ABL, but not the mutant. Whereas mice transplanted with p210 BCR/ABL exhibit myeloid disease with expansion of monocytes and neutrophils, mice transplanted with the mutant predominantly exhibit expansion of neutrophils, polycythemia, and increased lifespan. The increased disease latency is associated with expansion of megakaryocyte-erythrocyte progenitors, a decrease in common myeloid progenitors, and reduced ß-catenin signaling in the bone marrow of the diseased mice. These observations support a model in which p210 BCR/ABL may influence lineage-specific leukemic expansion by directly binding and phosphorylating ß-catenin and altering its transcriptional activity. They further suggest that the interaction may play a role in chronic phase disease progression.


Assuntos
Proteínas de Fusão bcr-abl/metabolismo , Leucemia Mielogênica Crônica BCR-ABL Positiva/metabolismo , Ubiquitina/metabolismo , beta Catenina/metabolismo , Animais , Sítios de Ligação , Transplante de Medula Óssea , Linhagem Celular , Modelos Animais de Doenças , Progressão da Doença , Feminino , Proteínas de Fusão bcr-abl/química , Imunofenotipagem , Leucemia Mielogênica Crônica BCR-ABL Positiva/mortalidade , Leucemia Mielogênica Crônica BCR-ABL Positiva/terapia , Camundongos , Fosforilação , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Proteínas Tirosina Quinases/metabolismo , Transdução de Sinais , Fatores de Transcrição TCF/metabolismo
4.
J Allied Health ; 42(1): e7-10, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23471291

RESUMO

Multiple technology based tools have been used to enhance skill development in allied health education, which now includes virtual learning environments. The purpose of this study was to explore whether, and how, this latest instructional technology is being adapted in allied health education. An online survey was circulated to all Association of Schools of Allied Health Professions (ASAHP) member institutions and focused on three broad areas of virtual learning environments: the uses of, the perceived pros and cons of, and the outcomes of utilizing them. Results show 40% (17 of 42) of the respondent use some form of the technology. The use of virtual learning technology in other healthcare professions (e.g., medicine) demonstrates the potential benefits to allied health education.


Assuntos
Pessoal Técnico de Saúde/educação , Simulação por Computador , Ensino/métodos , Interface Usuário-Computador , Instrução por Computador/métodos , Humanos , Inquéritos e Questionários , Estados Unidos
5.
Cancer Res ; 66(12): 6250-7, 2006 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-16778200

RESUMO

Virtually all patients with chronic myelogenous leukemia (CML) express an aberrant protein (p210 Bcr-Abl) that contains NH2-terminal sequences from Bcr fused to COOH-terminal sequences from Abl. In a yeast two-hybrid screen, we have identified TSG101 as a binding partner for Bcr. Because TSG101 is a subunit of the mammalian endosomal sorting complex required for transport (ESCRT), which regulates protein sorting during endosomal trafficking, this association suggests that Bcr may have a related cellular function. The docking site for TSG101 has been mapped to the COOH terminus of Bcr, indicating that this interaction may be disrupted in CML. Overexpression studies with full-length TSG101 and Bcr reveal that this interaction can be recapitulated in mammalian cells. The association can also be observed between natively expressed proteins in a panel of hematopoietic and nonhematopoietic cell lines, where a second subunit of the ESCRT complex, vacuolar sorting protein 28 (Vps28), was also found to interact with Bcr. Both Bcr and TSG101 exhibit a punctate cytoplasmic distribution and seem to colocalize in HeLa cells, which would be consistent with an in vivo association. Bacterially purified Bcr and TSG101 also bind, suggesting that the interaction is direct and is not dependent on ubiquitination. Disruption of the endosomal pathway with an ATPase-defective Vps4 mutant results in the cellular redistribution of Bcr, and suppression of Bcr in HeLa cells by small interfering RNA impairs epidermal growth factor receptor turnover. Taken together, these observations suggest that Bcr is a component of the mammalian ESCRT complexes and plays an important role in cellular trafficking of growth factor receptors.


Assuntos
Endossomos/metabolismo , Receptores ErbB/metabolismo , Proteínas Proto-Oncogênicas c-bcr/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Células 3T3 , ATPases Associadas a Diversas Atividades Celulares , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/metabolismo , Animais , Proteínas de Ligação a DNA/metabolismo , Complexos Endossomais de Distribuição Requeridos para Transporte , Proteínas Ativadoras de GTPase/metabolismo , Células HL-60 , Células HeLa , Humanos , Células K562 , Camundongos , Ligação Proteica , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Frações Subcelulares/metabolismo , Fatores de Transcrição/metabolismo , Ubiquitina/metabolismo , ATPases Vacuolares Próton-Translocadoras
6.
J Biol Chem ; 281(23): 16043-51, 2006 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-16613852

RESUMO

Dbs was identified in a cDNA-based expression screen for sequences that can cause malignant growth when expressed in murine fibroblasts. In previous studies we have shown that Dbs is a Rho-specific guanine nucleotide exchange factor that can activate RhoA and/or Cdc42 in a cell-specific manner. In this current study we have used a combination of genetic and pharmacological approaches to examine the relative contributions of RhoA x PRK and RhoA x ROCK signaling to Dbs transformation. Our analysis indicates that ROCK is activated in Dbs-transformed cells and that Dbs transformation is dependent upon ROCK I activity. In contrast, there appears to be no requirement for PRK activation in Dbs transformation. Dbs transformation is also associated with increased phosphorylation of myosin light chain and stress fiber formation, both of which occur in a ROCK-dependent manner. Suppression of myosin light chain expression by small interfering RNAs impairs Dbs focus formation, thus establishing a direct link between actinomyosin contraction and Rho-specific guanine nucleotide exchange factor transformation.


Assuntos
Fatores de Troca do Nucleotídeo Guanina/fisiologia , Cadeias Leves de Miosina/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Animais , Western Blotting , Peptídeos e Proteínas de Sinalização Intracelular , Camundongos , Células NIH 3T3 , Fosforilação , RNA Interferente Pequeno , Fatores de Troca de Nucleotídeo Guanina Rho , Quinases Associadas a rho
7.
Mol Biol Cell ; 16(3): 1152-64, 2005 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15635100

RESUMO

Polyadenylation-induced translation is an important regulatory mechanism during metazoan development. During Xenopus oocyte meiotic progression, polyadenylation-induced translation is regulated by CPEB, which is activated by phosphorylation. XGef, a guanine exchange factor, is a CPEB-interacting protein involved in the early steps of progesterone-stimulated oocyte maturation. We find that XGef influences early oocyte maturation by directly influencing CPEB function. XGef and CPEB interact during oogenesis and oocyte maturation and are present in a c-mos messenger ribonucleoprotein (mRNP). Both proteins also interact directly in vitro. XGef overexpression increases the level of CPEB phosphorylated early during oocyte maturation, and this directly correlates with increased Mos protein accumulation and acceleration of meiotic resumption. To exert this effect, XGef must retain guanine exchange activity and the interaction with CPEB. Overexpression of a guanine exchange deficient version of XGef, which interacts with CPEB, does not enhance early CPEB phosphorylation. Overexpression of a version of XGef that has significantly reduced interaction with CPEB, but retains guanine exchange activity, decreases early CPEB phosphorylation and delays oocyte maturation. Injection of XGef antibodies into oocytes blocks progesterone-induced oocyte maturation and early CPEB phosphorylation. These findings indicate that XGef is involved in early CPEB activation and implicate GTPase signaling in this process.


Assuntos
Fatores de Troca do Nucleotídeo Guanina/genética , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Oócitos/metabolismo , Fatores de Transcrição/metabolismo , Proteínas de Xenopus/genética , Proteínas de Xenopus/metabolismo , Animais , Células COS , Cromatografia Líquida , GTP Fosfo-Hidrolases/metabolismo , Genes Reporter , Glutationa Transferase/metabolismo , Humanos , Immunoblotting , Imunoprecipitação , Espectrometria de Massas , Meiose , Fosforilação , Plasmídeos/metabolismo , Progesterona/metabolismo , Ligação Proteica , Proteínas Quinases/metabolismo , Estrutura Terciária de Proteína , RNA/metabolismo , RNA Mensageiro/metabolismo , Proteínas Recombinantes/química , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais , Fatores de Tempo , Xenopus laevis , Fatores de Poliadenilação e Clivagem de mRNA
8.
J Biol Chem ; 280(4): 2807-17, 2005 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-15531584

RESUMO

Dbs is a Rho-specific guanine nucleotide exchange factor that was identified in a screen for proteins whose overexpression cause deregulated growth in murine fibroblasts. Dbs contains multiple recognizable motifs including a centrally located Rho-specific guanine nucleotide exchange factor domain, a COOH-terminal Src homology 3 domain, two spectrin-like repeats, and a recently identified NH(2)-terminal Sec14 homology domain. The transforming potential of Dbs is substantially activated by the removal of inhibitory sequences that lie outside of the core catalytic sequences, and in this current study we mapped this inhibition to the Sec14 domain. Surprisingly removal of the NH(2) terminus did not alter the catalytic activity of Dbs in vivo but rather altered its subcellular distribution. Whereas full-length Dbs was distributed primarily in a perinuclear structure that coincides with a marker for the Golgi apparatus, removal of the Sec14 domain was associated with translocation of Dbs to the cell periphery where it accumulated within membrane ruffles and lamellipodia. However, translocation of Dbs and the concomitant changes in the actin cytoskeleton were not sufficient to fully activate Dbs transformation. The Sec14 domain also forms intramolecular contacts with the pleckstrin homology domain, and these contacts must also be relieved to achieve full transforming activity. Collectively these observations suggest that the Sec14 domain regulates Dbs transformation through at least two distinct mechanisms, neither of which appears to directly influence the in vivo exchange activity of the protein.


Assuntos
Proteínas de Transporte/química , Proteínas de Transporte/fisiologia , Regulação da Expressão Gênica , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Fatores de Troca do Nucleotídeo Guanina/fisiologia , Animais , Catálise , Linhagem Celular , Deleção de Genes , Vetores Genéticos , Complexo de Golgi/metabolismo , Humanos , Imunoprecipitação , Metabolismo dos Lipídeos , Camundongos , Modelos Biológicos , Mutação , Células NIH 3T3 , Ligação Proteica , Estrutura Terciária de Proteína , Fatores de Troca de Nucleotídeo Guanina Rho , Proteínas rho de Ligação ao GTP/metabolismo , Domínios de Homologia de src
9.
J Biol Chem ; 279(13): 12786-93, 2004 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-14701795

RESUMO

Dbs is a Rho-specific guanine nucleotide exchange factor that was identified in a screen for proteins whose expression causes deregulated growth in NIH 3T3 mouse fibroblasts. Although Rac1 has not been shown to be a substrate for Dbs in either in vitro or in vivo assays, the Rat ortholog of Dbs (Ost) has been shown to bind specifically to GTP.Rac1 in vitro. The dependence of the Rac1/Dbs interaction on GTP suggests that Dbs may in fact be an effector for Rac1. Here we show that the interaction between activated Rac1 and Dbs can be recapitulated in mammalian cells and that the Rac1 docking site resides within the pleckstrin homology domain of Dbs. This interaction is specific for Rac1 and is not observed between Rac1 and several other members of the Rho-specific guanine nucleotide exchange factor family. Co-expression of Dbs with activated Rac1 causes enhanced focus forming activity and elevated levels of GTP.RhoA in NIH 3T3 cells, indicating that Dbs is activated by the interaction. Consistent with this, activated Rac1 co-localizes with Dbs in NIH 3T3 cells, and natively expressed Rac1 relocalizes in response to Dbs expression. To summarize, we have characterized a surprisingly direct pleckstrin homology domain-mediated mechanism through which Rho GTPases can become functionally linked.


Assuntos
Proteínas Sanguíneas/química , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Fosfoproteínas/química , Proteínas rac1 de Ligação ao GTP/metabolismo , Animais , Sítios de Ligação , Western Blotting , Catálise , Linhagem Celular , Regulação da Expressão Gênica , Humanos , Camundongos , Microscopia de Fluorescência , Células NIH 3T3 , Fosfatidilinositóis/química , Testes de Precipitina , Ligação Proteica , Estrutura Terciária de Proteína , Fatores de Troca de Nucleotídeo Guanina Rho , Transfecção , Proteína cdc42 de Ligação ao GTP/metabolismo , Proteína rhoA de Ligação ao GTP/química , Proteína rhoA de Ligação ao GTP/metabolismo
10.
Dev Biol ; 255(2): 383-98, 2003 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-12648498

RESUMO

XGef was isolated in a screen for proteins interacting with CPEB, a regulator of mRNA translation in early Xenopus development. XGef is a Rho-family guanine nucleotide exchange factor and activates Cdc42 in mammalian cells. Endogenous XGef (58 kDa) interacts with recombinant CPEB, and recombinant XGef interacts with endogenous CPEB in Xenopus oocytes. Injection of XGef antibodies into stage VI Xenopus oocytes blocks progesterone-induced oocyte maturation and prevents the polyadenylation and translation of c-mos mRNA; injection of XGef rescues these events. Overexpression of XGef in oocytes accelerates progesterone-induced oocyte maturation and the polyadenylation and translation of c-mos mRNA. Overexpression of a nucleotide exchange deficient version of XGef, which retains the ability to interact with CPEB, no longer accelerates oocyte maturation or Mos synthesis, suggesting that XGef exchange factor activity is required for the influence of overexpressed XGef on oocyte maturation. XGef overexpression continues to accelerate c-mos polyadenylation in the absence of Mos protein, but does not stimulate MAPK phosphorylation, MPF activation, or oocyte maturation, indicating that XGef may function through the Mos pathway to influence oocyte maturation. These results suggest that XGef may be an early acting component of the progesterone-induced oocyte maturation pathway.


Assuntos
Fatores de Troca do Nucleotídeo Guanina/metabolismo , Oócitos/crescimento & desenvolvimento , Oócitos/metabolismo , Fatores de Transcrição/metabolismo , Proteínas de Xenopus , Xenopus/crescimento & desenvolvimento , Xenopus/metabolismo , Fatores de Poliadenilação e Clivagem de mRNA/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Genes mos , Fatores de Troca do Nucleotídeo Guanina/genética , Técnicas In Vitro , Dados de Sequência Molecular , Oócitos/efeitos dos fármacos , Progesterona/farmacologia , Biossíntese de Proteínas , Proteínas Proto-Oncogênicas c-mos/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Homologia de Sequência de Aminoácidos , Fatores de Transcrição/genética , Xenopus/genética , Proteína cdc42 de Ligação ao GTP/metabolismo , Fatores de Poliadenilação e Clivagem de mRNA/genética
11.
J Biol Chem ; 278(20): 18393-400, 2003 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-12637522

RESUMO

Dbl family members are guanine nucleotide exchange factors specific for Rho guanosine triphosphatases (GTPases) and invariably possess tandem Dbl (DH) and pleckstrin homology (PH) domains. Dbs, a Dbl family member specific for Cdc42 and RhoA, exhibits transforming activity when overexpressed in NIH 3T3 mouse fibroblasts. In this study, the PH domain of Dbs was mutated to impair selectively either guanine nucleotide exchange or phosphoinositide binding in vitro and resulting physiological alterations were assessed. As anticipated, substitution of residues within the PH domain of Dbs integral to the interface with GTPases reduced nucleotide exchange and eliminated the ability of Dbs to transform NIH 3T3 cells. More interestingly, substitutions within the PH domain that prevent interaction with phosphoinositides yet do not alter in vitro activation of GTPases also do not transform NIH 3T3 cell and fail to activate RhoA in vivo despite proper subcellular localization. Therefore, the PH domain of Dbs serves multiple roles in the activation of GTPases and cannot be viewed as a simple membrane-anchoring device. In particular, the data suggest that binding of phosphoinositides to the PH domain within the context of membrane surfaces may direct orientations or conformations of the linked DH and PH domains to regulate GTPases activation.


Assuntos
Fatores de Troca do Nucleotídeo Guanina/metabolismo , Fatores de Troca do Nucleotídeo Guanina/fisiologia , Proteínas rho de Ligação ao GTP/metabolismo , Células 3T3 , Animais , Western Blotting , Membrana Celular/metabolismo , Análise Mutacional de DNA , DNA Complementar/metabolismo , Ativação Enzimática , Ensaio de Imunoadsorção Enzimática , Camundongos , Modelos Moleculares , Ligação Proteica , Estrutura Terciária de Proteína , Fatores de Troca de Nucleotídeo Guanina Rho , Espectrometria de Fluorescência , Frações Subcelulares/metabolismo , Fatores de Tempo , Proteína rhoA de Ligação ao GTP/metabolismo
12.
Curr Biol ; 13(5): 437-41, 2003 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-12620195

RESUMO

Bcr is a multifunctional protein that is the fusion partner for Abl (p210 Bcr-Abl) in Philadelphia chromosome positive leukemias. We have identified c-Myc as a binding partner for Bcr in both yeast and mammalian cells. We are also able to observe interactions between natively expressed c-Myc and Bcr in leukemic cell lines. Although Bcr and Max have overlapping binding sites on c-Myc, Bcr cannot interact with Max, or with the c-Myc.Max heterodimer. Bcr expression blocks activation of c-Myc-responsive genes, as well as the transformed phenotype induced by coexpression of c-Myc and H-Ras, and this finding suggests that one function of Bcr is to limit the activity of c-Myc. However, Bcr does not block c-Myc function by preventing its nuclear localization. Interestingly, increased Bcr dosage in COS-7 and K-562 cells correlates with a reduction in c-Myc protein levels, suggesting that Bcr may in fact be limiting c-Myc activity by regulating its stability. These data indicate that Bcr is a novel regulator of c-Myc function whose disrupted expression may contribute to the high level of c-Myc protein that is observed in Bcr-Abl transformed cells.


Assuntos
Proteínas Oncogênicas/metabolismo , Proteínas Tirosina Quinases , Proteínas Proto-Oncogênicas c-myc/metabolismo , Proteínas Proto-Oncogênicas , Animais , Humanos , Proteínas Proto-Oncogênicas c-bcr , Leveduras/metabolismo
13.
Mol Cell Biol ; 22(19): 6895-905, 2002 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-12215546

RESUMO

Dbs is a Rho-specific guanine nucleotide exchange factor (RhoGEF) that exhibits transforming activity when overexpressed in NIH 3T3 mouse fibroblasts. Like many RhoGEFs, the in vitro catalytic activity of Dbs is not limited to a single substrate. It can catalyze the exchange of GDP for GTP on RhoA and Cdc42, both of which are expressed in most cell types. This lack of substrate specificity, which is relatively common among members of the RhoGEF family, complicates efforts to determine the molecular basis of their transforming activity. We have recently determined crystal structures of several RhoGEFs bound to their cognate GTPases and have used these complexes to predict structural determinants dictating the specificities of coupling between RhoGEFs and GTPases. Guided by this information, we mutated Dbs to alter significantly its relative exchange activity for RhoA versus Cdc42 and show that the transformation potential of Dbs correlates with exchange on RhoA but not Cdc42. Supporting this conclusion, oncogenic Dbs activates endogenous RhoA but not endogenous Cdc42 in NIH 3T3 cells. Similarly, a competitive inhibitor that blocks RhoA activation also blocks Dbs-mediated transformation. In conclusion, this study highlights the usefulness of specificity mutants of RhoGEFs as tools to genetically dissect the multiple signaling pathways potentially activated by overexpressed or oncogenic RhoGEFs. These ideas are exemplified for Dbs, which is strongly implicated in the transformation of NIH 3T3 cells via RhoA and not Cdc42.


Assuntos
Transformação Celular Neoplásica/metabolismo , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Proteína rhoA de Ligação ao GTP/metabolismo , Células 3T3 , Animais , Fibroblastos/citologia , Fibroblastos/metabolismo , Fatores de Troca do Nucleotídeo Guanina/química , Fatores de Troca do Nucleotídeo Guanina/genética , Guanosina Difosfato/metabolismo , Guanosina Trifosfato/metabolismo , Camundongos , Modelos Moleculares , Mutagênese Sítio-Dirigida , Ligação Proteica/fisiologia , Estrutura Terciária de Proteína/fisiologia , Fatores de Troca de Nucleotídeo Guanina Rho , Relação Estrutura-Atividade , Especificidade por Substrato , Transfecção , Proteína cdc42 de Ligação ao GTP/química , Proteína cdc42 de Ligação ao GTP/genética , Proteína cdc42 de Ligação ao GTP/metabolismo , Proteína rhoA de Ligação ao GTP/química , Proteína rhoA de Ligação ao GTP/genética
14.
Oncogene ; 21(30): 4601-12, 2002 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-12096337

RESUMO

The oncogenic fusion protein p210 Bcr-Abl is causally associated with virtually all cases of chronic myelogenous leukemia. The wild-type Bcr product has several recognizable structural and functional motifs including a domain that contains guanine nucleotide exchange activity for Rho family GTPases (DH/PH domain). Although this domain is retained within p210 Bcr-Abl, it has no known signaling activities in vivo. Here we report that a fragment of Bcr that encodes the isolated DH/PH domain is a potent activator of the NF-kappaB transcription factor. Within the context of full length Bcr, this activity is regulated by proximal flanking sequences that suppress the DH/PH domain encoded guanine nucleotide exchange activity. NF-kappaB activation by Bcr is not mediated by nuclear translocation, but rather by p38 mitogen-activated protein kinase (MAPK)-dependent modification of the RelA/p65 transactivation domain. Although we were able to demonstrate that Bcr can function as an exchange factor for Cdc42 in vivo, NF-kappaB activation appears to occur via a Cdc42-independent mechanism. These studies constitute direct evidence that the Bcr RhoGEF domain can function in vivo, and identify a new signaling activity that may contribute to the transforming potential of p210 Bcr-Abl.


Assuntos
Fatores de Troca do Nucleotídeo Guanina/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , NF-kappa B/metabolismo , Proteínas Oncogênicas/química , Proteínas Oncogênicas/metabolismo , Proteínas Tirosina Quinases , Proteínas Proto-Oncogênicas , Células 3T3 , Animais , Sítios de Ligação , Células COS , Núcleo Celular/metabolismo , Ensaio de Desvio de Mobilidade Eletroforética , Proteínas de Fusão bcr-abl/química , Proteínas de Fusão bcr-abl/metabolismo , Sistema de Sinalização das MAP Quinases , Camundongos , NF-kappa B/antagonistas & inibidores , NF-kappa B/química , Regiões Promotoras Genéticas/genética , Estrutura Terciária de Proteína , Proteínas Proto-Oncogênicas c-bcr , Elementos de Resposta/genética , Fatores de Troca de Nucleotídeo Guanina Rho , Ativação Transcricional , Transfecção , Fator de Necrose Tumoral alfa/farmacologia , Proteína cdc42 de Ligação ao GTP/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno , Proteínas rac1 de Ligação ao GTP/metabolismo , Proteína rhoA de Ligação ao GTP/metabolismo
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