Specific SHP-2 partitioning in raft domains triggers integrin-mediated signaling via Rho activation

Copyright © by The Rockefeller University PressCell signaling does not occur randomly over the cell surface, but is integrated within cholesterol-enriched membrane domains, termed rafts. By targeting SHP-2 to raft domains or to a non-raft plasma membrane fraction, we studied the functional role of rafts in signaling. Serumdepleted, nonattached cells expressing the raft SHP-2 form, but not non-raft SHP-2, display signaling events resembling those observed after fibronectin attachment, such as 1 integrin clustering, 397 Y-FAK phosphorylation, and ERK activation, and also increases Rho-GTP levels. Expression of C the dominant negative N19Rho abrogates raft-SHP-2–induced signaling, suggesting that Rho activation is a downstream event in SHP-2 signaling. Expression of a catalytic inactive SHP-2 mutant abrogates the adhesion-induced feedback inhibition of Rho activity, suggesting that SHP-2 contributes to adhesion-induced suppression of Rho activity. Because raft recruitment of SHP-2 occurs physiologically after cell attachment, these results provide a mechanism by which SHP-2 may influence cell adhesion and migration by spatially regulating Rho activity.Peer reviewe

Herramienta de seguimiento funcional y superación de interfase durante la reeducación del futbolista lesionado

Conscious about the importance of a sure injured footballer ́s returnto play, and knowing the complex process of decision relative to theideal moment for the return in group training, we present a tool ofwork and register that while permitting control us the follow-up andthe evolution of our sportsman, complement to the objectives tests remainders carried out (conditional, functional, psychological, ...)collaborating in the determination of the suitable moment of return.Conscientes de la importancia de una vuelta segura del futbolista lesionado, y sabedores del complejo proceso de toma de decisión respecto al momento de la vuelta al entrenamiento grupal, presentamos una herramienta de trabajo y registro que a la vez que nos permita controlar el seguimiento y la evolución de nuestro deportista, complemente al resto de pruebas objetivas realizadas (condicionales, funcionales, psicológicas, ...) colaborando en la determinación del momento idóneo de retorno

Efecto del nivel de experiencia clínica del examinador sobre la validez de criterio y fiabilidad inter-sesión de cinco medidas del rango de movimiento de la flexión dorsal del tobillo

El objetivo de este estudio fue analizar el efecto que el diferente grado de experiencia del examinador tiene sobre la validez de criterio y fiabilidad inter-sesión de las medidas de rango de movimiento de la flexión dorsal del tobillo (ROMFDT) obtenidas en las pruebas: flexión dorsal del tobillo pasiva en decúbito prono y rodilla flexionada (FDPAS), zancada coninclinómetro (FDZAN-INC) y cinta métrica (FDZAN-MET), zancada modificada con taburete (FDZAN-TAB) y zancada modificada con cajón (FDZAN-CAJ). Un total de 17 deportistas recreativos completaron este estudio. Cada participante fue evaluado por dos examinadores con distinto nivel de experiencia (experto y novel) del ROMFDT empleando 5 pruebas exploratorias diferentes en dos sesiones distintas. Los resultados muestran bajos valores de validez para el examinador novel en todas las pruebas de valoración del ROMFDTexcepto en la prueba FDZAN-INC (error típico de la estimación estandarizado = 0,5 [pequeño]; Pearson = 0,85 [moderado]; kappa = 0,74 [buena]). El examinador experto presentó niveles altos de fiabilidad inter-sesión en las pruebas FDZAN-INC, FDZAN-MET y FDZAN-CAJ y valores aceptables en las pruebas FDPAS y FDZAN-TAB. El examinador novel obtuvo valores aceptables de fiabilidad en toda las pruebas de valoración excepto en la prueba FDPAS, que fueron considerados como no aceptables. Por lo tanto, se recomienda que tanto los examinadores expertos como noveles utilicen la prueba FDZAN-INC para: (a) identificar a personas con restringida o normal movilidad de la flexión dorsal del tobillo; y (b) monitorizar la eficacia de los programas de intervención aplicados en caso de ser necesarios

Dynamic redistribution of raft domains as an organizing platform for signaling during cell chemotaxis

Spatially restricted activation of signaling molecules governs critical aspects of cell migration; the mechanism by which this is achieved nonetheless remains unknown. Using time-lapse confocal microscopy, we analyzed dynamic redistribution of lipid rafts in chemoattractant-stimulated leukocytes expressing glycosyl phosphatidylinositol–anchored green fluorescent protein (GFP-GPI). Chemoattractants induced persistent GFP-GPI redistribution to the leading edge raft (L raft) and uropod rafts of Jurkat, HL60, and dimethyl sulfoxide–differentiated HL60 cells in a pertussis toxin–sensitive, actin-dependent manner. A transmembrane, nonraft GFP protein was distributed homogeneously in moving cells. A GFP-CCR5 chimera, which partitions in L rafts, accumulated at the leading edge, and CCR5 redistribution coincided with recruitment and activation of phosphatidylinositol-3 kinase γ in L rafts in polarized, moving cells. Membrane cholesterol depletion impeded raft redistribution and asymmetric recruitment of PI3K to the cell side facing the chemoattractant source. This is the first direct evidence that lipid rafts order spatial signaling in moving mammalian cells, by concentrating the gradient sensing machinery at the leading edge

Blocking of HIV-1 Infection by Targeting CD4 to Nonraft Membrane Domains

Human immunodeficiency virus (HIV)-1 infection depends on multiple lateral interactions between the viral envelope and host cell receptors. Previous studies have suggested that these interactions are possible because HIV-1 receptors CD4, CXCR4, and CCR5 partition in cholesterol-enriched membrane raft domains. We generated CD4 partitioning mutants by substituting or deleting CD4 transmembrane and cytoplasmic domains and the CD4 ectodomain was unaltered. We report that all CD4 mutants that retain raft partitioning mediate HIV-1 entry and CD4-induced Lck activation independently of their transmembrane and cytoplasmic domains. Conversely, CD4 ectodomain targeting to a nonraft membrane fraction results in a CD4 receptor with severely diminished capacity to mediate Lck activation or HIV-1 entry, although this mutant binds gp120 as well as CD4wt. In addition, the nonraft CD4 mutant inhibits HIV-1 X4 and R5 entry in a CD4+ cell line. These results not only indicate that HIV-1 exploits host membrane raft domains as cell entry sites, but also suggest new strategies for preventing HIV-1 infection

Specific SHP-2 partitioning in raft domains triggers integrin-mediated signaling via Rho activation

Cell signaling does not occur randomly over the cell surface, but is integrated within cholesterol-enriched membrane domains, termed rafts. By targeting SHP-2 to raft domains or to a non-raft plasma membrane fraction, we studied the functional role of rafts in signaling. Serum-depleted, nonattached cells expressing the raft SHP-2 form, but not non-raft SHP-2, display signaling events resembling those observed after fibronectin attachment, such as β(1) integrin clustering, (397)Y-FAK phosphorylation, and ERK activation, and also increases Rho-GTP levels. Expression of the dominant negative N19Rho abrogates raft-SHP-2–induced signaling, suggesting that Rho activation is a downstream event in SHP-2 signaling. Expression of a catalytic inactive SHP-2 mutant abrogates the adhesion-induced feedback inhibition of Rho activity, suggesting that SHP-2 contributes to adhesion-induced suppression of Rho activity. Because raft recruitment of SHP-2 occurs physiologically after cell attachment, these results provide a mechanism by which SHP-2 may influence cell adhesion and migration by spatially regulating Rho activity

CCR5 Expression Influences the Progression of Human Breast Cancer in a p53-dependent Manner

Chemokines are implicated in tumor pathogenesis, although it is unclear whether they affect human cancer progression positively or negatively. We found that activation of the chemokine receptor CCR5 regulates p53 transcriptional activity in breast cancer cells through pertussis toxin–, JAK2-, and p38 mitogen–activated protein kinase–dependent mechanisms. CCR5 blockade significantly enhanced proliferation of xenografts from tumor cells bearing wild-type p53, but did not affect proliferation of tumor xenografts bearing a p53 mutation. In parallel, data obtained in a primary breast cancer clinical series showed that disease-free survival was shorter in individuals bearing the CCR5Δ32 allele than in CCR5 wild-type patients, but only for those whose tumors expressed wild-type p53. These findings suggest that CCR5 activity influences human breast cancer progression in a p53-dependent manner

Statins Inhibit HIV-1 Infection by Down-regulating Rho Activity

Human immunodeficiency virus (HIV)-1 infectivity requires actin-dependent clustering of host lipid raft–associated receptors, a process that might be linked to Rho guanosine triphosphatase (GTPase) activation. Rho GTPase activity can be negatively regulated by statins, a family of drugs used to treat hypercholesterolemia in man. Statins mediate inhibition of Rho GTPases by impeding prenylation of small G proteins through blockade of 3-hydroxy-3-methylglutaryl coenzyme A reductase. We show that statins decreased viral load and increased CD4+ cell counts in acute infection models and in chronically HIV-1–infected patients. Viral entry and exit was reduced in statin-treated cells, and inhibition was blocked by the addition of l-mevalonate or of geranylgeranylpyrophosphate, but not by cholesterol. Cell treatment with a geranylgeranyl transferase inhibitor, but not a farnesyl transferase inhibitor, specifically inhibited entry of HIV-1–pseudotyped viruses. Statins blocked Rho-A activation induced by HIV-1 binding to target cells, and expression of the dominant negative mutant RhoN19 inhibited HIV-1 envelope fusion with target cell membranes, reducing cell infection rates. We suggest that statins have direct anti–HIV-1 effects by targeting Rho

Programa SALUD 5-10: Programa para el tratamiento del sobrepeso y la obesidad en niños de 5 a 10 años: Antecedentes, Diseño y Metodología

Obesity is a particularly expensive and costly in economic and social terms disease for both people who suffer as public health institutions. Therefore, in recent decades, various international and national organizations have shown great concern for its implications, going to be treated as a real social problem. According to the World Health Organization, Spain is one of the EU countries with the highest prevalence of overweight children as recorded by 33% in the population between 5 and 17 years, whereas in Europe one in four children has overweight or obese. Furthermore, Spain is one of the countries where this disease has grown (in the eighties the prevalence was 15%). Several systematic reviews assessing the effectiveness of intervention programs based on increasing physical activity and dietary control of overweight and / or obesity in children and adolescents highlight the need to design specific programs for schoolchildren, and to assess objectively the effectiveness of such long-term programs in children and adolescents are overweight or obese. The aim of this paper is to describe the design and methodology used in 5-10 Health Program, a program that has been designed with the objective of addressing overweight and obesity in schoolchildren in the age group between 5-10 years.La obesidad es una enfermedad especialmente cara y costosa en términos económicos y sociales tanto para las personas que la padecen como para las instituciones públicas sanitarias. Por ello, en las últimas décadas distintas organizaciones internacionales y nacionales han mostrado una enorme preocupación por sus implicaciones, pasando a ser tratado como un verdadero problema social. Según la Organización Mundial de la Salud, España es uno de los países de la Unión Europea con mayor prevalencia de sobrepeso infantil, ya que registra un 33% en la población entre 5 y 17 años, mientras que en Europa uno de cada cuatro niños tiene sobrepeso o es obeso. Además, España es uno de los países donde más ha crecido esta enfermedad (en la década de los ochenta la prevalencia era de un 15%). Diversas revisiones sistemáticas que evalúan la efectividad de los programas de intervención basados en el aumento de la actividad física y el control dietético sobre el sobrepeso y/u obesidad en población infantil y adolescente resaltan la necesidad de diseñar programas específicos para los escolares, así como valorar objetivamente la eficacia de dichos programas a largo plazo en niños y adolescentes con sobrepeso u obesidad. El objetivo del presente trabajo es describir el diseño y metodología utilizada en el Programa SALUD 5-10, un programa que ha sido diseñado con el objetivo de abordar el sobrepeso y la obesidad en escolares de una franja de edad entre 5 a 10 años