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1.
Clin Infect Dis ; 2023 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-37739479

RESUMO

BACKGROUND: Public health officials are responding to an outbreak of fungal meningitis among patients who received procedures under epidural anesthesia at two clinics (River Side Surgical Center and Clinica K-3) in Matamoros, Mexico, during January 1-May 13, 2023. This report describes outbreak epidemiology and outlines interim diagnostic and treatment recommendations. METHODS: Interim recommendations for diagnosis and management were developed by the Mycoses Study Group Research Education and Consortium (MSGERC) based on the clinical experience of clinicians caring for patients during the current outbreak or during previous outbreaks of healthcare-associated fungal meningitis in Durango, Mexico, and the United States. RESULTS: As of July 7, 2023, the situation has evolved into a multistate and multinational fungal meningitis outbreak. A total of 185 residents in 22 U.S. states and jurisdictions have been identified who might be at risk of fungal meningitis because they received epidural anesthesia at the clinics of interest in 2023. Among these patients, 11 suspected, 10 probable, and 10 confirmed U.S. cases have been diagnosed, with severe vascular complications and eight deaths occurring. Fusarium solani species complex has been identified as the causative agent, with antifungal susceptibility testing of a single isolate demonstrating poor in vitro activity for most available antifungals. Currently, triple therapy with intravenous voriconazole, liposomal amphotericin B, and fosmanogepix is recommended. CONCLUSIONS: Efforts to understand the source of this outbreak and optimal treatment approaches are ongoing, but infectious diseases physicians should be aware of available treatment recommendations. New information will be available on CDC's website.

2.
Ann N Y Acad Sci ; 1489(1): 17-29, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33155324

RESUMO

For years, experts have warned that a global pandemic was only a matter of time. Indeed, over the past two decades, several outbreaks and pandemics, from SARS to Ebola, have tested our ability to respond to a disease threat and provided the opportunity to refine our preparedness systems. However, when a novel coronavirus with human-to-human transmissibility emerged in China in 2019, many of these systems were found lacking. From international disputes over data and resources to individual disagreements over the effectiveness of facemasks, the COVID-19 pandemic has revealed several vulnerabilities. As of early November 2020, the WHO has confirmed over 46 million cases and 1.2 million deaths worldwide. While the world will likely be reeling from the effects of COVID-19 for months, and perhaps years, to come, one key question must be asked, How can we do better next time? This report summarizes views of experts from around the world on how lessons from past pandemics have shaped our current disease preparedness and response efforts, and how the COVID-19 pandemic may offer an opportunity to reinvent public health and healthcare systems to be more robust the next time a major challenge appears.


Assuntos
COVID-19/epidemiologia , COVID-19/terapia , Atenção à Saúde , Pandemias , Saúde Pública , Congressos como Assunto , Humanos
3.
Trends Biochem Sci ; 30(8): 423-6, 2005 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15996870

RESUMO

Given the numerous mechanisms that regulate the activity of Rho GTPases and the multiple effectors for Rho proteins, how is specificity achieved when transducing signals via Rho GTPase-regulated molecular networks? The finding that the scaffold protein hCNK1 links Rho guanine-nucleotide-exchange factors and Rho to JNK (c-Jun N-terminal kinase), while limiting stress-fiber formation and serum-response-factor activation, suggests that scaffold proteins govern the selection of signal outputs, thus helping to solve the Rho GTPase-signaling puzzle.


Assuntos
Transdução de Sinais , Proteínas rho de Ligação ao GTP/metabolismo , Animais , Citoesqueleto/metabolismo , Regulação da Expressão Gênica , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Especificidade por Substrato
4.
BMJ Glob Health ; 5(12)2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33303514

RESUMO

Today's global health challenges in underserved communities include the growing burden of cancer and other non-communicable diseases (NCDs); infectious diseases (IDs) with epidemic and pandemic potential such as COVID-19; and health effects from catastrophic 'all hazards' disasters including natural, industrial or terrorist incidents. Healthcare disparities in low-income and middle-income countries and in some rural areas in developed countries make it a challenge to mitigate these health, socioeconomic and political consequences on our globalised society. As with IDs, cancer requires rapid intervention and its effective medical management and prevention encompasses the other major NCDs. Furthermore, the technology and clinical capability for cancer care enables management of NCDs and IDs. Global health initiatives that call for action to address IDs and cancer often focus on each problem separately, or consider cancer care only a downstream investment to primary care, missing opportunities to leverage investments that could support broader capacity-building. From our experience in health disparities, disaster preparedness, government policy and healthcare systems we have initiated an approach we call flex-competence which emphasises a systems approach from the outset of program building that integrates investment among IDs, cancer, NCDs and disaster preparedness to improve overall healthcare for the local community. This approach builds on trusted partnerships, multi-level strategies and a healthcare infrastructure providing surge capacities to more rapidly respond to and manage a wide range of changing public health threats.


Assuntos
Doenças Transmissíveis/epidemiologia , Doenças Transmissíveis/terapia , Prestação Integrada de Cuidados de Saúde/tendências , Saúde Global , Disparidades em Assistência à Saúde , Neoplasias/epidemiologia , Neoplasias/terapia , COVID-19/epidemiologia , COVID-19/terapia , Humanos , Pandemias , SARS-CoV-2
5.
Disaster Med Public Health Prep ; 13(5-6): 995-1010, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31203830

RESUMO

A national need is to prepare for and respond to accidental or intentional disasters categorized as chemical, biological, radiological, nuclear, or explosive (CBRNE). These incidents require specific subject-matter expertise, yet have commonalities. We identify 7 core elements comprising CBRNE science that require integration for effective preparedness planning and public health and medical response and recovery. These core elements are (1) basic and clinical sciences, (2) modeling and systems management, (3) planning, (4) response and incident management, (5) recovery and resilience, (6) lessons learned, and (7) continuous improvement. A key feature is the ability of relevant subject matter experts to integrate information into response operations. We propose the CBRNE medical operations science support expert as a professional who (1) understands that CBRNE incidents require an integrated systems approach, (2) understands the key functions and contributions of CBRNE science practitioners, (3) helps direct strategic and tactical CBRNE planning and responses through first-hand experience, and (4) provides advice to senior decision-makers managing response activities. Recognition of both CBRNE science as a distinct competency and the establishment of the CBRNE medical operations science support expert informs the public of the enormous progress made, broadcasts opportunities for new talent, and enhances the sophistication and analytic expertise of senior managers planning for and responding to CBRNE incidents.


Assuntos
Derramamento de Material Biológico/prevenção & controle , Vazamento de Resíduos Químicos/prevenção & controle , Serviços Médicos de Emergência/métodos , Substâncias Explosivas/efeitos adversos , Liberação Nociva de Radioativos/prevenção & controle , Planejamento em Desastres/organização & administração , Planejamento em Desastres/tendências , Serviços Médicos de Emergência/tendências , Humanos
6.
Mol Cell Biol ; 23(19): 7030-43, 2003 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-12972619

RESUMO

Polypeptide growth factors, such as platelet-derived growth factor (PDGF), promote the reinitiation of DNA synthesis and cell growth through multiple intracellular signaling pathways that converge in the nucleus to regulate the activity of transcription factors, thereby controlling the expression of growth-promoting genes. Among them, the AP-1 (activating protein-1) family of transcription factors, including c-Fos and c-Jun family members, plays a key role, as AP-1 activity is potently activated by PDGF and is required to stimulate cell proliferation. However, the nature of the pathways connecting PDGF receptors to AP-1 is still poorly defined. In this study, we show that PDGF regulates AP-1 by stimulating the expression and function of c-Fos through extracellular signal-regulated kinase (ERK). The latter involves the direct phosphorylation by ERK of multiple residues in the carboxyl-terminal transactivation domain of c-Fos, which results in its increased transcriptional activity. Interestingly, the phosphorylation of c-Fos by ERK was required for the ability of PDGF and serum to stimulate the activity of c-Fos as well as AP-1-dependent transcription. Furthermore, we provide evidence that the ERK-dependent activation of c-Fos is an integral component of the mitogenic pathway by which PDGF regulates normal and aberrant cell growth.


Assuntos
Transformação Celular Neoplásica , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Fator de Crescimento Derivado de Plaquetas/fisiologia , Proteínas Proto-Oncogênicas c-fos/metabolismo , Transativadores/metabolismo , Fator de Transcrição AP-1/metabolismo , Células 3T3 , Substituição de Aminoácidos , Animais , Linhagem Celular , Glutationa Transferase/metabolismo , Histonas/metabolismo , Humanos , Camundongos , Modelos Biológicos , Fosforilação , Mutação Puntual , Processamento de Proteína Pós-Traducional , Estrutura Terciária de Proteína , Proteínas Proto-Oncogênicas c-fos/química , Proteínas Proto-Oncogênicas c-fos/genética , Receptores do Fator de Crescimento Derivado de Plaquetas/metabolismo , Proteínas Recombinantes de Fusão/isolamento & purificação , Proteínas Recombinantes de Fusão/metabolismo , Transdução de Sinais , Ativação Transcricional
7.
Mol Cell Biol ; 22(6): 1792-803, 2002 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11865058

RESUMO

The Drosophila melanogaster JUN N-terminal kinase (DJNK) and DPP (decapentaplegic) signal transduction pathways coordinately regulate epithelial cell sheet movement during the process of dorsal closure in the embryo. By a genetic screen of mutations affecting dorsal closure in Drosophila, we have now identified a multidomain protein, connector of kinase to AP-1 (cka), that functions in the DJNK pathway and controls the localized expression of dpp in the leading-edge cells. We have also investigated how CKA acts. This unique molecule forms a complex with HEP (DJNKK), BSK (DJNK), DJUN, and DFOS. Complex formation activates BSK kinase, which in turn phosphorylates and activates DJUN and DFOS. These data suggest that CKA represents a novel molecule regulating AP-1 activity by organizing a molecular complex of kinases and transcription factors, thus coordinating the spatial-temporal expression of AP-1-regulated genes.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Transdução de Sinais/fisiologia , Células 3T3 , Animais , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster , Proteínas de Insetos/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno , Substâncias Macromoleculares , Camundongos , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Dados de Sequência Molecular , Fosforilação , Estrutura Terciária de Proteína/fisiologia , Proteínas Tirosina Quinases/metabolismo , Homologia de Sequência de Aminoácidos , Fator de Transcrição AP-1/metabolismo , Fatores de Transcrição/metabolismo , Transcrição Gênica/fisiologia , Transfecção
8.
Biosecur Bioterror ; 12(5): 284-91, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25254917

RESUMO

In 2014, the United States in partnership with international organizations and nearly 30 partner countries launched the Global Health Security Agenda (GHSA) to accelerate progress to improve prevention, detection, and response capabilities for infectious disease outbreaks that can cause public health emergencies. Objective 9 of the GHSA calls for improved global access to medical countermeasures and establishes as a target the development of national policy frameworks for sending and receiving medical countermeasures from and to international partners during public health emergencies. The term medical countermeasures refers to vaccines, antimicrobials, therapeutics, and diagnostics that address the public health and medical consequences of chemical, biological, radiological, and nuclear events; pandemic influenza; and emerging infectious diseases. They are stockpiled by a few countries to protect their own populations and by international organizations, such as the World Health Organization (WHO), for the international community, typically for recipients with limited resources. However, as observed during the 2009 H1N1 influenza pandemic, legal, regulatory, logistical, and funding barriers slowed the ability of WHO and countries to quickly deploy or receive vaccine. Had the 2009 H1N1 influenza pandemic been more severe, the world would have been ill prepared to cope with the global demand for rapid access to medical countermeasures. This article summarizes the US government efforts to develop a national framework to deploy medical countermeasures internationally and a number of engagements to develop regional and international mechanisms, thus increasing global capacity to respond to public health emergencies.


Assuntos
Bioterrorismo/prevenção & controle , Fortalecimento Institucional , Controle de Doenças Transmissíveis/organização & administração , Surtos de Doenças/prevenção & controle , Saúde Global , Cooperação Internacional , Medidas de Segurança , Animais , Bioterrorismo/legislação & jurisprudência , Controle de Doenças Transmissíveis/legislação & jurisprudência , Surtos de Doenças/legislação & jurisprudência , Saúde Global/legislação & jurisprudência , Acessibilidade aos Serviços de Saúde , Humanos , Vírus da Influenza A Subtipo H1N1 , Influenza Humana/epidemiologia , Influenza Humana/prevenção & controle , Cooperação Internacional/legislação & jurisprudência , Objetivos Organizacionais , Organização Mundial da Saúde
10.
J Biol Chem ; 282(47): 34510-24, 2007 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-17881360

RESUMO

Heme oxygenase-1 (HO-1), an inducible enzyme that metabolizes the heme group, is highly expressed in human Kaposi sarcoma lesions. Its expression is up-regulated by the G protein-coupled receptor from the Kaposi sarcoma-associated herpes virus (vGPCR). Although recent evidence shows that HO-1 contributes to vGPCR-induced tumorigenesis and vascular endothelial growth factor (VEGF) expression, the molecular steps that link vGPCR to HO-1 remain unknown. Here we show that vGPCR induces HO-1 expression and transformation through the Galpha(12/13) family of heterotrimeric G proteins and the small GTPase RhoA. Targeted small hairpin RNA knockdown expression of Galpha(12), Galpha(13), or RhoA and inhibition of RhoA activity impair vGPCR-induced transformation and ho-1 promoter activity. Knockdown expression of RhoA also reduces vGPCR-induced VEFG-A secretion and blocks tumor growth in a murine allograft tumor model. NIH-3T3 cells expressing constitutively activated Galpha(13) or RhoA implanted in nude mice develop tumors displaying spindle-shaped cells that express HO-1 and VEGF-A, similarly to vGPCR-derived tumors. RhoAQL-induced tumor growth is reduced 80% by small hairpin RNA-mediated knockdown expression of HO-1 in the implanted cells. Likewise, inhibition of HO-1 activity by chronic administration of the HO-1 inhibitor tin protoporphyrin IX to mice reduces RhoAQL-induced tumor growth by 70%. Our study shows that vGPCR induces HO-1 expression through the Galpha(12/13)/RhoA axes and shows for the first time a potential role for HO-1 as a therapeutic target in tumors where RhoA has oncogenic activity.


Assuntos
Transformação Celular Viral , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/metabolismo , Heme Oxigenase-1/metabolismo , Herpesvirus Humano 8/metabolismo , Receptores de Quimiocinas/metabolismo , Proteína rhoA de Ligação ao GTP/metabolismo , Animais , Transformação Celular Viral/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Heme Oxigenase-1/antagonistas & inibidores , Humanos , Camundongos , Camundongos Nus , Células NIH 3T3 , Fármacos Fotossensibilizantes/farmacologia , Regiões Promotoras Genéticas/genética , Protoporfirinas/farmacologia , Receptores de Quimiocinas/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
11.
J Biol Chem ; 281(16): 11332-46, 2006 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-16476737

RESUMO

Heme oxygenase-1 (HO-1), the inducible enzyme responsible for the rate-limiting step in the heme catabolism, is expressed in AIDS-Kaposi sarcoma (KS) lesions. Its expression is up-regulated by the Kaposi sarcoma-associated herpesvirus (KSHV) in endothelial cells, but the mechanisms underlying KSHV-induced HO-1 expression are still unknown. In this study we investigated whether the oncogenic G protein-coupled receptor (KSHV-GPCR or vGPCR), one of the key KSHV genes involved in KS development, activated HO-1 expression. Here we show that vGPCR induces HO-1 mRNA and protein levels in fibroblasts and endothelial cells. Moreover, targeted knock-down gene expression of HO-1 by small hairpin RNA and chemical inhibition of HO-1 enzymatic activity by tin protoporphyrin IX (SnPP), impaired vGPCR-induced survival, proliferation, transformation, and vascular endothelial growth factor (VEGF)-A expression. vGPCR-expressing cells implanted in the dorsal flank of nude mice developed tumors with elevated HO-1 expression and activity. Chronic administration of SnPP to the implanted mice, under conditions that effectively blocked HO-1 activity and VEGF-A expression in the transplanted cells, strikingly reduced tumor growth, without apparent side effects. On the contrary, administration of the HO-1 inducer cobalt protoporphyrin (CoPP) further enhanced vGPCR-induced tumor growth. These data postulate HO-1 as an important mediator of vGPCR-induced tumor growth and suggest that inhibition of intratumoral HO-1 activity by SnPP may be a potential therapeutic strategy.


Assuntos
Inibidores Enzimáticos/farmacologia , Heme Oxigenase-1/antagonistas & inibidores , Herpesvirus Humano 8/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Animais , Anexina A5/farmacologia , Apoptose , Western Blotting , Proliferação de Células , Sobrevivência Celular , Meios de Cultura Livres de Soro/metabolismo , DNA/metabolismo , Relação Dose-Resposta a Droga , Células Endoteliais/metabolismo , Fibroblastos/metabolismo , Técnica Indireta de Fluorescência para Anticorpo , Genes Reporter , Heme/química , Heme Oxigenase (Desciclizante)/metabolismo , Heme Oxigenase-1/metabolismo , Imuno-Histoquímica , Luciferases/metabolismo , Metaloporfirinas/metabolismo , Camundongos , Camundongos Nus , Modelos Biológicos , Células NIH 3T3 , Transplante de Neoplasias , Neoplasias/metabolismo , Regiões Promotoras Genéticas , Protoporfirinas/química , Protoporfirinas/metabolismo , RNA/metabolismo , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Tempo , Transfecção , Regulação para Cima , Fator A de Crescimento do Endotélio Vascular/metabolismo
12.
J Biol Chem ; 280(19): 18842-52, 2005 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-15708845

RESUMO

Exposure to sources of UV radiation, such as sunlight, induces a number of cellular alterations that are highly dependent on its ability to affect gene expression. Among them, the rapid activation of genes coding for two subfamilies of proto-oncoproteins, Fos and Jun, which constitute the AP-1 transcription factor, plays a key role in the subsequent regulation of expression of genes involved in DNA repair, cell proliferation, cell cycle arrest, death by apoptosis, and tissue and extracellular matrix remodeling proteases. Besides being regulated at the transcriptional level, Jun and Fos transcriptional activities are also regulated by phosphorylation as a result of the activation of intracellular signaling cascades. In this regard, the phosphorylation of c-Jun by UV-induced JNK has been readily documented, whereas a role for Fos proteins in UV-mediated responses and the identification of Fos-activating kinases has remained elusive. Here we identify p38 MAPKs as proteins that can associate with c-Fos and phosphorylate its transactivation domain both in vitro and in vivo. This phosphorylation is transduced into changes in its transcriptional ability as p38-activated c-Fos enhances AP1-driven gene expression. Our findings indicate that as a consequence of the activation of stress pathways induced by UV light, endogenous c-Fos becomes a substrate of p38 MAPKs and, for the first time, provide evidence that support a critical role for p38 MAPKs in mediating stress-induced c-Fos phosphorylation and gene transcription activation. Using a specific pharmacological inhibitor for p38alpha and -beta, we found that most likely these two isoforms mediate UV-induced c-Fos phosphorylation in vivo. Thus, these newly described pathways act concomitantly with the activation of c-Jun by JNK/MAPKs, thereby contributing to the complexity of AP1-driven gene transcription regulation.


Assuntos
Proteínas Proto-Oncogênicas c-fos/química , Fator de Transcrição AP-1/química , Proteínas Quinases p38 Ativadas por Mitógeno/química , Transporte Ativo do Núcleo Celular , Animais , Apoptose , Sítios de Ligação , Western Blotting , Ciclo Celular , Linhagem Celular , Núcleo Celular/metabolismo , DNA/química , Dano ao DNA , Eletroforese em Gel de Poliacrilamida , Inibidores Enzimáticos/farmacologia , Matriz Extracelular/metabolismo , Técnica Indireta de Fluorescência para Anticorpo , Genes Reporter , Glutationa Transferase/metabolismo , Células HeLa , Humanos , Luciferases/metabolismo , Camundongos , Microscopia de Fluorescência , Modelos Biológicos , Células NIH 3T3 , Fosforilação , Isoformas de Proteínas , Proteínas Recombinantes de Fusão/química , Frações Subcelulares , Fatores de Tempo , Transcrição Gênica , Ativação Transcricional , Transfecção , Técnicas do Sistema de Duplo-Híbrido , Raios Ultravioleta , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
13.
Mol Cell ; 14(1): 29-41, 2004 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-15068801

RESUMO

RhoA regulates the actin cytoskeleton and the expression of genes associated with cell proliferation. This includes c-fos and c-jun, which are members of the AP1 family of transcription factors that play a key role in normal and aberrant cell growth. Whereas RhoA stimulates the c-fos SRE by a recently elucidated mechanism that is dependent on actin treadmilling, how RhoA regulates c-jun is still poorly understood. We found that RhoA stimulates c-jun expression through ROCK, but independently from the ability of ROCK to promote actin polymerization. Instead, we found that ROCK activates JNK, which then phosphorylates c-Jun and ATF2 when bound to the c-jun promoter. Thus, ROCK represents a point of signal divergence downstream from RhoA, as it promotes actin reorganization and the consequent expression from the c-fos SRE, while a parallel pathway connects ROCK to JNK, thereby stimulating c-jun expression. Ultimately, these pathways converge in the nucleus to regulate AP1 activity.


Assuntos
Proteínas Quinases Ativadas por Mitógeno/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas c-jun/metabolismo , Transdução de Sinais/fisiologia , Proteína rhoA de Ligação ao GTP/metabolismo , Fatores de Despolimerização de Actina , Actinas/metabolismo , Fator 2 Ativador da Transcrição , Animais , Linhagem Celular , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Citoesqueleto/metabolismo , Ativação Enzimática , Inibidores Enzimáticos/metabolismo , Regulação da Expressão Gênica , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Proteínas Quinases JNK Ativadas por Mitógeno , Quinases Lim , Lisofosfolipídeos/metabolismo , Camundongos , Proteínas dos Microfilamentos/metabolismo , Células NIH 3T3 , Regiões Promotoras Genéticas , Proteínas Quinases/metabolismo , Proteínas Proto-Oncogênicas c-jun/genética , Fatores de Transcrição/metabolismo , Quinases Associadas a rho
14.
J Biol Chem ; 278(36): 34339-46, 2003 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-12810717

RESUMO

The proto-oncogene c-Src has been implicated in the development and progression of a number of human cancers including those of colon and breast. Accumulating evidence indicates that activated alleles of Src may induce cell transformation through Ras-ERK-dependent and -independent pathways. Here we show that Rac1 activity is strongly elevated in Src-transformed cells and that this small G protein is a critical component of the pathway connecting oncogenic Src with cell transformation. We further show that Vav2 and the ubiquitously expressed Rac1 guanine nucleotide exchange factor Tiam1 are phosphorylated in tyrosine residues in cells transfected with active and oncogenic Src. Moreover, phosphorylation of Tiam1 in cells treated with pervanadate, a potent inhibitor of tyrosine phosphatases, was partially inhibited by the Src inhibitor SU6656. Using truncated mutants of Tiam1, we demonstrate that multiple sites can be tyrosine-phosphorylated by Src. Furthermore, Tiam1 cooperated with Src to induce activation of Rac1 in vivo and the formation of membrane ruffles. Similarly, activation of JNK and the c-jun promoter by Src were also potently increased by Tiam1. Together, these results suggest that Vav2 and Tiam1 may act as downstream effectors of Src, thereby regulating Rac1-dependent pathways that participate in Src-induced cell transformation.


Assuntos
Proteínas Quinases JNK Ativadas por Mitógeno , Proteínas Oncogênicas/fisiologia , Proteínas/fisiologia , Proteínas Proto-Oncogênicas pp60(c-src)/metabolismo , Proteínas rac1 de Ligação ao GTP/metabolismo , Proteínas rac1 de Ligação ao GTP/fisiologia , Células 3T3 , Alelos , Animais , Sítios de Ligação , Catálise , Linhagem Celular , Transformação Celular Neoplásica , DNA/metabolismo , Ativação Enzimática , Inibidores Enzimáticos/farmacologia , GTP Fosfo-Hidrolases/metabolismo , Genes Reporter , Fatores de Troca do Nucleotídeo Guanina , Humanos , Indóis/farmacologia , MAP Quinase Quinase 4 , Camundongos , Microscopia de Fluorescência , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Mutação , Fosforilação , Plasmídeos/metabolismo , Regiões Promotoras Genéticas , Proto-Oncogene Mas , Proteínas Proto-Oncogênicas c-jun/metabolismo , Proteínas Proto-Oncogênicas c-vav , Sulfonamidas/farmacologia , Proteína 1 Indutora de Invasão e Metástase de Linfoma de Células T , Fatores de Tempo , Transfecção , Tirosina/metabolismo , Vanadatos/farmacologia
15.
J Biol Chem ; 278(47): 46814-25, 2003 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-12954641

RESUMO

Although the ability of G protein-coupled receptors to stimulate normal and aberrant cell growth has been intensely investigated, the precise nature of the molecular mechanisms underlying their transforming potential are still not fully understood. In this study, we have taken advantage of the potent mitogenic effect of thrombin and the focus-forming activity of one of its receptors, protease-activated receptor-1, to dissect how this receptor coupled to Galphai, Galphaq/11, and Galpha12/13 transduces signals from the membrane to the nucleus to initiate transcriptional events involved in cell transformation. Using endogenous and transfected thrombin receptors in NIH 3T3 cells, ectopic expression of muscarinic receptors coupled to Galphaq and Galphai, and chimeric G protein alpha subunits and murine fibroblasts deficient in Galphaq/11, and Galpha12/13, we show here that, although coupling to Galphai is sufficient to induce ERK activation, the ability to couple to Galphaq and/or Galpha13 is necessary to induce c-jun expression and cell transformation. Furthermore, we show that Galphaq and Galpha13 can initiate the activation of MAPK cascades, including JNK, p38, and ERK5, which in turn regulate the activity of transcription factors controlling expression from the c-jun promoter. We also present evidence that c-Jun and the kinases regulating its expression are integral components of the transforming pathway initiated by protease-activated receptor-1.


Assuntos
Transformação Celular Neoplásica , Sistema de Sinalização das MAP Quinases/fisiologia , Proteínas Quinases Ativadas por Mitógeno/biossíntese , Receptor PAR-1/fisiologia , Transdução de Sinais , Células 3T3 , Animais , Subunidades alfa G12-G13 de Proteínas de Ligação ao GTP/metabolismo , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/metabolismo , Regulação da Expressão Gênica , Proteínas Quinases JNK Ativadas por Mitógeno , Camundongos , Proteínas Quinases Ativadas por Mitógeno/genética , Regiões Promotoras Genéticas , Receptor PAR-1/metabolismo , Trombina/metabolismo , Transcrição Gênica
16.
J Biol Chem ; 278(50): 50024-30, 2003 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-14523011

RESUMO

Pro-inflammatory cytokines, environmental stresses, as well as receptor tyrosine kinases regulate the activity of JNK. In turn, JNK phosphorylates Jun members of the AP-1 family of transcription factors, thereby controlling processes as different as cell growth, differentiation, and apoptosis. Still, very few targets of the JNK-Jun pathway have been identified. Here we show that JNK is required for the induction of c-myc expression by PDGF. Furthermore, we identify a phylogenetically conserved AP-1-responsive element in the promoter of the c-myc proto-oncogene that recruits in vivo the c-Jun and JunD AP-1 family members and controls the PDGF-dependent transactivation of the c-myc promoter. These findings suggest the existence of a novel biochemical route linking tyrosine kinase receptors, such as those for PDGF, and c-myc expression through JNK activation of AP-1 transcription factors. They also provide a novel potential mechanism by which both JNK and Jun proteins may exert either their proliferative or apoptotic potential by stimulating the expression of the c-myc proto-oncogene.


Assuntos
Proteínas Quinases JNK Ativadas por Mitógeno , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Fator de Crescimento Derivado de Plaquetas/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo , Transdução de Sinais , Fator de Transcrição AP-1/metabolismo , Animais , Apoptose , Sequência de Bases , Northern Blotting , Western Blotting , Divisão Celular , Cromatina/metabolismo , Drosophila , Ativação Enzimática , Genes Reporter , Humanos , MAP Quinase Quinase 4 , Sistema de Sinalização das MAP Quinases , Camundongos , Modelos Biológicos , Dados de Sequência Molecular , Mutação , Células NIH 3T3 , Filogenia , Testes de Precipitina , Regiões Promotoras Genéticas , Estrutura Terciária de Proteína , Proteínas Tirosina Quinases/metabolismo , Proto-Oncogene Mas , RNA Mensageiro/metabolismo , Proteínas Recombinantes/química , Ativação Transcricional , Transfecção
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