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1.
Nutrients ; 14(20)2022 Oct 14.
Artículo en Inglés | MEDLINE | ID: mdl-36296974

RESUMEN

BACKGROUND: International strategies to reduce chronic diseases have called for a reduction in the amounts of saturated fat (SAFA), trans fat (TFA), salt and sugars in the global food supply. This paper describes the development approach and potential impact of a set of standards for these nutrients to drive food (re)formulation. METHODS: To set the standards, WHO nutrient guidelines for daily intake were translated into product group specific standards. The impact of reformulation towards these standards on population nutrient intakes was modelled using the food consumption data of five countries: UK, France, US, Brazil and China. The impact of the TFA standards could not be modelled due to lack of data. RESULTS: (Re)formulation of foods and beverages towards these standards would substantially decrease mean population intakes of energy, sodium, SAFA and sugars, with reductions up to 30%. CONCLUSIONS: These science-based standards for nutrients to limit could drive impactful reductions in energy, sodium, SAFA and sugars in food and beverage products, enabling mean population intakes to move closer to WHO nutrient guidelines.


Asunto(s)
Sodio , Azúcares , Valor Nutritivo , Bebidas , Nutrientes , Ácidos Grasos , Organización Mundial de la Salud , Ingestión de Energía
3.
Sci Data ; 8(1): 196, 2021 08 02.
Artículo en Inglés | MEDLINE | ID: mdl-34341357

RESUMEN

Coral reef management and conservation stand to benefit from improved high-resolution global mapping. Yet classifications underpinning large-scale reef mapping to date are typically poorly defined, not shared or region-specific, limiting end-users' ability to interpret outputs. Here we present Reef Cover, a coral reef geomorphic zone classification, developed to support both producers and end-users of global-scale coral reef habitat maps, in a transparent and version-based framework. Scalable classes were created by focusing on attributes that can be observed remotely, but whose membership rules also reflect deep knowledge of reef form and functioning. Bridging the divide between earth observation data and geo-ecological knowledge of reefs, Reef Cover maximises the trade-off between applicability at global scales, and relevance and accuracy at local scales. Two case studies demonstrate application of the Reef Cover classification scheme and its scientific and conservation benefits: 1) detailed mapping of the Cairns Management Region of the Great Barrier Reef to support management and 2) mapping of the Caroline and Mariana Island chains in the Pacific for conservation purposes.


Asunto(s)
Conservación de los Recursos Naturales , Arrecifes de Coral , Tecnología de Sensores Remotos , Australia
4.
Sci Data ; 8(1): 84, 2021 03 16.
Artículo en Inglés | MEDLINE | ID: mdl-33727570

RESUMEN

This paper describes benthic coral reef community composition point-based field data sets derived from georeferenced photoquadrats using machine learning. Annually over a 17 year period (2002-2018), data were collected using downward-looking photoquadrats that capture an approximately 1 m2 footprint along 100 m-1500 m transect surveys distributed along the reef slope and across the reef flat of Heron Reef (28 km2), Southern Great Barrier Reef, Australia. Benthic community composition for the photoquadrats was automatically interpreted through deep learning, following initial manual calibration of the algorithm. The resulting data sets support understanding of coral reef biology, ecology, mapping and dynamics. Similar methods to derive the benthic data have been published for seagrass habitats, however here we have adapted the methods for application to coral reef habitats, with the integration of automatic photoquadrat analysis. The approach presented is globally applicable for various submerged and benthic community ecological applications, and provides the basis for further studies at this site, regional to global comparative studies, and for the design of similar monitoring programs elsewhere.


Asunto(s)
Biota , Arrecifes de Coral , Animales , Australia
5.
Sci Data ; 4: 170060, 2017 05 09.
Artículo en Inglés | MEDLINE | ID: mdl-28485717

RESUMEN

Seagrass above, below and total biomass, density and leaf area, length and width were quantified at a species level for 122 sites over three sampling periods in Moreton Bay, Australia. Core samples were collected in two regions: (1) a high water quality region with varying species assemblages and canopy complexity (98 sites); and (2) along a turbidity gradient in the bay (24 sites within four locations). Core samples were collected using a 15 cm diameter×20 cm long corer. Seagrass dry biomass per component was quantified per species present in each sample. A total of 220 biomass and density data records are included, 130 from the high water quality region and 90 from the turbidity gradient. These data provide a detailed assessment of biomass, density and leaf metrics per species sampled from Moreton Bay over 2012-2013. In future, these can be used as a baseline to assess seasonal and spatial variation within the bay, within the region and among regions.


Asunto(s)
Biomasa , Algas Marinas , Australia , Bahías , Monitoreo del Ambiente
6.
Sci Data ; 2: 150040, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26396742

RESUMEN

This paper describes seagrass species and percentage cover point-based field data sets derived from georeferenced photo transects. Annually or biannually over a ten year period (2004-2014) data sets were collected using 30-50 transects, 500-800 m in length distributed across a 142 km(2) shallow, clear water seagrass habitat, the Eastern Banks, Moreton Bay, Australia. Each of the eight data sets include seagrass property information derived from approximately 3000 georeferenced, downward looking photographs captured at 2-4 m intervals along the transects. Photographs were manually interpreted to estimate seagrass species composition and percentage cover (Coral Point Count excel; CPCe). Understanding seagrass biology, ecology and dynamics for scientific and management purposes requires point-based data on species composition and cover. This data set, and the methods used to derive it are a globally unique example for seagrass ecological applications. It provides the basis for multiple further studies at this site, regional to global comparative studies, and, for the design of similar monitoring programs elsewhere.


Asunto(s)
Alismatales , Alismatales/química , Australia , Monitoreo del Ambiente
7.
Obesity (Silver Spring) ; 22(10): 2131-6, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24990101

RESUMEN

OBJECTIVE: Simple aeration of food matrices with gas has previously been shown to generate immediate suppression of appetite, though duration of effects has not been shown. This research tested whether liquids aerated with nitrous oxide (N2 O) to achieve high in-body stability could produce enhanced and sustained effects on eating motivations. METHODS: In two randomized cross-over studies, appetite ratings were collected for 240 min. In Study 1, 24 volunteers consumed a full portion liquid (325 ml, 190 kcal) or aerated (1,000 ml, 190 kcal) drink at 0 min, or half portions of liquid (162 ml, 95 kcal) or aerated (500 ml, 95 kcal) drink at 0 and 120 min. In Study 2, assessing the effect of N2 O itself, 23 volunteers consumed water saturated with N2 O or with CO2 10 min after a mini-drink (180 kcal). Appetite was quantified by area-under-the curve (AUC) and time-to-return-to-baseline (TTRTB). RESULTS: Full- and half-size aerated drinks decreased hunger AUC over 4 h by 26 and 50% (P < 0.0001) versus the respective liquid versions. Effects were also sustained significantly longer (TTRTB from 203 to 335 and from 173 to 286 min, respectively). In Study 2, N2 O and CO2 had similar effects on appetite ratings. CONCLUSIONS: Aeration of foods using appropriate microstructural design has a powerful effect on eating motivations.


Asunto(s)
Regulación del Apetito , Ingestión de Líquidos , Óxido Nitroso , Adulto , Estudios Cruzados , Femenino , Gases , Humanos , Masculino , Persona de Mediana Edad , Estómago/fisiología
8.
Mol Biol Cell ; 23(23): 4601-10, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23051739

RESUMEN

The epithelial zonula adherens (ZA) is a specialized adhesive junction where actin dynamics and myosin-driven contractility coincide. The junctional cytoskeleton is enriched in myosin II, which generates contractile force to support junctional tension. It is also enriched in dynamic actin filaments, which are replenished by ongoing actin assembly. In this study we sought to pursue the relationship between actin assembly and junctional contractility. We demonstrate that WAVE2-Arp2/3 is a major nucleator of actin assembly at the ZA and likely acts in response to junctional Rac signaling. Furthermore, WAVE2-Arp2/3 is necessary for junctional integrity and contractile tension at the ZA. Maneuvers that disrupt the function of either WAVE2 or Arp2/3 reduced junctional tension and compromised the ability of cells to buffer side-to-side forces acting on the ZA. WAVE2-Arp2/3 disruption depleted junctions of both myosin IIA and IIB, suggesting that dynamic actin assembly may support junctional tension by facilitating the local recruitment of myosin.


Asunto(s)
Proteína 2 Relacionada con la Actina/metabolismo , Proteína 3 Relacionada con la Actina/metabolismo , Actinas , Familia de Proteínas del Síndrome de Wiskott-Aldrich/metabolismo , Citoesqueleto de Actina/metabolismo , Citoesqueleto de Actina/ultraestructura , Complejo 2-3 Proteico Relacionado con la Actina/metabolismo , Complejo 2-3 Proteico Relacionado con la Actina/ultraestructura , Actinas/metabolismo , Actinas/ultraestructura , Uniones Adherentes/metabolismo , Uniones Adherentes/ultraestructura , Células CACO-2 , Epitelio/metabolismo , Humanos , Miosina Tipo IIA no Muscular/metabolismo , Miosina Tipo IIB no Muscular/metabolismo , Transducción de Señal
9.
Appetite ; 59(2): 601-9, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-22796948

RESUMEN

Current methods of analyzing appetite-related self-report data do not allow for representation or statistical comparison of results in terms of common units or response durations. Using data from 13 previous studies, we assessed the suitability of several alternative approaches (interpolation, linear regression, non-linear models) for quantitatively estimating and comparing time to return to baseline pre-prandial levels (TTRTB, min). Curve modeling using the Weibull distribution gave the best fit and ability to determine mean TTRTB values with 95% confidence intervals. We then applied this in a study comparing liquid meal replacers (MR, 190 kcal) to 3 'meals' of similar weight and equal or greater energy content (yogurt, 190 kcal; bagel with cream cheese and juice, 400 kcal; hamburger with bun and soft drink, 400 kcal). While area under the curve data did not significantly differ amongst these, TTRTB was significantly longer for MR than yogurt. When corrected for energy content, TTRTB (min/kcal) was greater for MR than all other treatments. While further method development and validation are needed, the Weibull modeling procedure appears most suitable for estimating and quantitatively comparing durations of appetite-related responses to foods, providing an absolute response measure that can be expressed in commonly understood units.


Asunto(s)
Bebidas , Comidas , Respuesta de Saciedad , Adolescente , Adulto , Apetito , Estudios Cruzados , Ingestión de Energía , Estudios de Evaluación como Asunto , Femenino , Humanos , Modelos Lineales , Masculino , Persona de Mediana Edad , Modelos Estadísticos , Dinámicas no Lineales , Yogur , Adulto Joven
10.
Nat Cell Biol ; 14(8): 818-828, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22750944

RESUMEN

The biological impact of Rho depends critically on the precise subcellular localization of its active, GTP-loaded form. This can potentially be determined by the balance between molecules that promote nucleotide exchange or GTP hydrolysis. However, how these activities may be coordinated is poorly understood. We now report a molecular pathway that achieves exactly this coordination at the epithelial zonula adherens. We identify an extramitotic activity of the centralspindlin complex, better understood as a cytokinetic regulator, which localizes to the interphase zonula adherens by interacting with the cadherin-associated protein, α-catenin. Centralspindlin recruits the RhoGEF, ECT2, to activate Rho and support junctional integrity through myosin IIA. Centralspindlin also inhibits the junctional localization of p190 B RhoGAP, which can inactivate Rho. Thus, a conserved molecular ensemble that governs Rho activation during cytokinesis is used in interphase cells to control the Rho GTPase cycle at the zonula adherens.


Asunto(s)
Uniones Adherentes/fisiología , Proteínas de Ciclo Celular/metabolismo , Epitelio/fisiología , Proteínas Activadoras de GTPasa/metabolismo , Proteínas Asociadas a Microtúbulos/metabolismo , Fosfoproteínas/metabolismo , Transducción de Señal , alfa Catenina/metabolismo , Animales , Células CACO-2 , Línea Celular , Línea Celular Tumoral , Perros , Epitelio/metabolismo , Femenino , Células HEK293 , Humanos , Microtúbulos , Proteínas Proto-Oncogénicas/metabolismo , Espectrometría de Fluorescencia
11.
Nat Cell Biol ; 13(8): 934-43, 2011 Jul 24.
Artículo en Inglés | MEDLINE | ID: mdl-21785420

RESUMEN

N-WASP is a major cytoskeletal regulator that stimulates Arp2/3-mediated actin nucleation. Here, we identify a nucleation-independent pathway by which N-WASP regulates the cytoskeleton and junctional integrity at the epithelial zonula adherens. N-WASP is a junctional protein whose depletion decreased junctional F-actin content and organization. However, N-WASP (also known as WASL) RNAi did not affect junctional actin nucleation, dominantly mediated by Arp2/3. Furthermore, the junctional effect of N-WASP RNAi was rescued by an N-WASP mutant that cannot directly activate Arp2/3. Instead, N-WASP stabilized newly formed actin filaments and facilitated their incorporation into apical rings at the zonula adherens. A major physiological effect of N-WASP at the zonula adherens thus occurs through a non-canonical pathway that is distinct from its capacity to activate Arp2/3. Indeed, the junctional impact of N-WASP was mediated by the WIP-family protein, WIRE, which binds to the N-WASP WH1 domain. We conclude that N-WASP-WIRE serves as an integrator that couples actin nucleation with the subsequent steps of filament stabilization and organization necessary for zonula adherens integrity.


Asunto(s)
Actinas/metabolismo , Uniones Adherentes/metabolismo , Citoesqueleto/metabolismo , Proteína Neuronal del Síndrome de Wiskott-Aldrich/metabolismo , Complejo 2-3 Proteico Relacionado con la Actina/metabolismo , Células CACO-2 , Proteínas Portadoras/metabolismo , Epitelio/metabolismo , Humanos , Proteínas de Microfilamentos , Mutación , Interferencia de ARN , Proteína Neuronal del Síndrome de Wiskott-Aldrich/antagonistas & inhibidores , Proteína Neuronal del Síndrome de Wiskott-Aldrich/genética
12.
Cell Adh Migr ; 5(4): 344-50, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21677511

RESUMEN

The process of epithelial lumenogenesis requires coordination of a network of signaling machinery communicated to each cell through subsequent cell divisions. Formation of a single hollow lumen has previously been shown to require Tuba, a Cdc42 GEF, for Cdc42 activation and correct spindle orientation. Using a Caco-2 model of lumenogenesis, we show that knockdown (KD) of the actin regulator N-WASP, causes a multilumen phenotype similar to Tuba KD. Defects in lumenogenesis in Tuba KD and N-WASP KD cells are observed at the two cell stage with inappropriate marking of the pre-apical patch (PAP) - the precursor to lumen formation. Strikingly, both Tuba and N-WASP depend on each other for localization to the PAP. We conclude that N-WASP functions cooperatively with Tuba to facilitate lumenogenesis and this requires the polyproline region of N-WASP.


Asunto(s)
Proteínas del Citoesqueleto/metabolismo , Células Epiteliales/metabolismo , Morfogénesis , Proteína Neuronal del Síndrome de Wiskott-Aldrich/metabolismo , Citoesqueleto de Actina/metabolismo , Antígenos CD , Células CACO-2 , Cadherinas/metabolismo , División Celular , Polaridad Celular , Clonación Molecular , Células Epiteliales/citología , Técnicas de Silenciamiento del Gen , Humanos , Lentivirus/genética , Péptidos/metabolismo , Interferencia de ARN , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Transducción de Señal , Huso Acromático/metabolismo , Transfección , Proteína de Unión al GTP cdc42/metabolismo
13.
Exp Dermatol ; 19(8): 723-9, 2010 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-20545758

RESUMEN

Although IL-1 is a known inflammatory cytokine during pathogen infection, the role of IL-1 in skin graft rejection, particularly where foreign antigen is expressed exclusively in keratinocytes, is less understood. Here, we use a syngeneic skin graft system, where antigens are expressed in epithelial cells via either a keratin 14 or keratin 5 promoter, to explore the role of IL-1 in graft rejection and induction of epithelial antigen-specific effector CD8(+) T-cell function. Keratin 5 ovalbumin (K5mOVA) transgenic skin grafts destined for rejection demonstrated increased expression of IL-1beta and its receptors compared to K14 HPV16 E7 transgenic grafts that do not reject spontaneously. Rejection of OVA grafts lacking the IL-1 receptor (IL-1R1) was delayed and associated with decreased numbers of antigen-specific CD8 T cells. In contrast, K14E7 grafts survived on immunocompetent, syngeneic recipients with decreased graft levels of IL-1beta and IL-1R1 and 2. However, in the absence of the IL-1 receptor antagonist, IL-1Ra, skin grafts were spontaneously rejected and an E7-specific CD8 T-cell response was primed. Thus, expression of the HPV16E7 oncoprotein in epithelial cells prevents IL-1beta-associated skin graft rejection and induction of antigen-specific CD8 T-cell responses. Enhancing IL-1beta signalling, via blocking of the IL-1 receptor antagonist, may represent an alternative strategy for treatment of HPV16E7-associated cancers.


Asunto(s)
Interleucina-1/metabolismo , Queratinocitos/metabolismo , Transducción de Señal/fisiología , Trasplante de Piel/fisiología , Animales , Rechazo de Injerto/metabolismo , Queratina-14/metabolismo , Queratina-5/metabolismo , Queratinocitos/citología , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Modelos Animales , Ovalbúmina/metabolismo , Proteínas E7 de Papillomavirus/metabolismo , Receptores de Interleucina-1/metabolismo
14.
Nat Cell Biol ; 12(7): 696-702, 2010 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-20543839

RESUMEN

Classic cadherin receptors cooperate with regulators of the actin cytoskeleton to control tissue organization in health and disease. At the apical junctions of epithelial cells, the cadherin ring of the zonula adherens (ZA) couples with a contiguous ring of actin filaments to support morphogenetic processes such as tissue integration and cellular morphology. However, the molecular mechanisms that coordinate adhesion and cytoskeleton at these junctions are poorly understood. Previously we identified non-muscle myosin II as a target of Rho signalling that supports cadherin junctions in mammalian epithelial cells. Myosin II has various cellular functions, which are increasingly attributable to the specific biophysical properties and regulation of its different isoforms. Here we report that myosin II isoforms have distinct and necessary roles at cadherin junctions. Although two of the three mammalian myosin II isoforms are found at the ZA, their localization is regulated by different upstream signalling pathways. Junctional localization of myosin IIA required E-cadherin adhesion, Rho/ROCK and myosin light-chain kinase, whereas junctional myosin IIB depended on Rap1. Further, these myosin II isoforms support E-cadherin junction integrity by different mechanisms. Myosin IIA RNA-mediated interference (RNAi) selectively perturbed the accumulation of E-cadherin in the apical ZA, decreased cadherin homophilic adhesion and disrupted cadherin clustering. In contrast, myosin IIB RNAi decreased filament content, altered dynamics, and increased the lateral movement of the perijunctional actin ring. Myosin IIA and IIB therefore identify two distinct functional modules, with different upstream signals that control junctional localization, and distinct functional effects. We propose that these two isoform-based modules cooperate to coordinate adhesion receptor and F-actin organization to form apical cadherin junctions.


Asunto(s)
Uniones Adherentes/metabolismo , Miosina Tipo IIA no Muscular/metabolismo , Miosina Tipo IIB no Muscular/metabolismo , Cadherinas/metabolismo , Línea Celular Tumoral , Humanos , Modelos Biológicos
15.
Obesity (Silver Spring) ; 18(4): 773-9, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-19680234

RESUMEN

Obesity is a major health problem in the developed and developing world. Many "functional" foods and ingredients are advocated for their effects on body composition but few have consistent scientific support for their efficacy. However, an increasing amount of mechanistic and clinical evidence is building for green tea (GT). This experiment was therefore undertaken to study the effects of a high-catechin GT on body composition in a moderately overweight Chinese population. In a randomized placebo-controlled trial, 182 moderately overweight Chinese subjects, consumed either two servings of a control drink (C; 30 mg catechins, 10 mg caffeine/day), one serving of the control drink and one serving of an extra high-catechin GT1 (458 mg catechins, 104 mg caffeine/day), two servings of a high-catechin GT2 (468 mg catechins, 126 mg caffeine/day) or two servings of the extra high-catechin GT3 (886 mg catechins, 198 mg caffeine/day) for 90 days. Data were collected at 0, 30, 60, and 90 days. We observed a decrease in estimated intra-abdominal fat (IAF) area of 5.6 cm(2) in the GT3 group. In addition, we found decreases of 1.9 cm in waist circumference and 1.2 kg body weight in the GT3 group vs. C (P < 0.05). We also observed reductions in total body fat (GT2, 0.7 kg, P < 0.05) and body fat % (GT1, 0.6%, P < 0.05). We conclude that consumption of two servings of an extra high-catechin GT leads to improvements in body composition and reduces abdominal fatness in moderately overweight Chinese subjects.


Asunto(s)
Fármacos Antiobesidad/uso terapéutico , Composición Corporal/efectos de los fármacos , Camellia sinensis/química , Catequina/uso terapéutico , Sobrepeso/tratamiento farmacológico , Fitoterapia , Extractos Vegetales/uso terapéutico , Grasa Abdominal/efectos de los fármacos , Tejido Adiposo/efectos de los fármacos , Adulto , Fármacos Antiobesidad/farmacología , Peso Corporal/efectos de los fármacos , Catequina/farmacología , Método Doble Ciego , Femenino , Alimentos Funcionales , Humanos , Grasa Intraabdominal/efectos de los fármacos , Masculino , Persona de Mediana Edad , Extractos Vegetales/farmacología , , Circunferencia de la Cintura/efectos de los fármacos
16.
Br J Nutr ; 102(8): 1187-94, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19445822

RESUMEN

Green tea may stimulate energy metabolism; however, it is unclear if acute effects are caused by specific catechins, caffeine or their combination. The objective of the present study was to examine the separate and combined effects of different catechins and caffeine on energy expenditure (EE) and fat oxidation over a single day. Fifteen healthy, normal-weight males received capsules containing placebo, caffeine alone (150 mg), or caffeine plus a catechin mixture (600 mg) enriched in either epigallocatechin-3-gallate (EGCG), epigallocatechin or a mix of catechins, in a randomised cross-over double-blinded design. On each test day EE, respiratory quotient (RQ) and substrate oxidation were measured under sedentary conditions in a respiratory chamber for 13.5 h. We found no significant treatment effect on EE (P = 0.20) or RQ (P = 0.68). EGCG with caffeine insignificantly raised EE and fat oxidation v. caffeine-only and placebo (EE 5.71 (SE 0.12) v. 5.68 (SE 0.14) v. 5.59 (SE 0.13) MJ/12.5 h, respectively; fat oxidation 84.8 (SE 5.2) v. 80.7 (SE 4.7) v. 76.8 (SE 4.0) g/12.5 h). Catechin/caffeine combinations at these dosages and mode of application had non-significant acute effects on EE and fat oxidation. The maximum observed effect on EE of about 2 % could still be meaningful for energy balance over much longer period of exposure. However, higher short-term effects reported in the literature may reflect variations in green tea extracts, added caffeine, or synergies with physical activity. The specific mechanisms and conditions that may underpin observed longer-term benefits of catechin-enriched green tea consumption on body composition remain to be confirmed.


Asunto(s)
Cafeína/farmacología , Catequina/farmacología , Metabolismo Energético/efectos de los fármacos , Actividad Motora/fisiología , Té/química , Adulto , Apetito/efectos de los fármacos , Estudios Cruzados , Método Doble Ciego , Epinefrina/orina , Frecuencia Cardíaca/efectos de los fármacos , Humanos , Masculino , Norepinefrina/orina , Oxidación-Reducción , Intercambio Gaseoso Pulmonar/fisiología , Adulto Joven
18.
Mol Biol Cell ; 18(8): 3214-23, 2007 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-17553930

RESUMEN

Cadherin-based cell-cell contacts are prominent sites for phosphotyrosine signaling, being enriched in tyrosine-phosphorylated proteins and tyrosine kinases and phosphatases. The functional interplay between cadherin adhesion and tyrosine kinase signaling, however, is complex and incompletely understood. In this report we tested the hypothesis that cadherin adhesion activates c-Src signaling and sought to assess its impact on cadherin function. We identified c-Src as part of a cadherin-activated cell signaling pathway that is stimulated by ligation of the adhesion receptor. However, c-Src has a biphasic impact on cadherin function, exerting a positive supportive role at lower signal strengths, but inhibiting function at high signal strengths. Inhibiting c-Src under circumstances when it is activated by cadherin adhesion decreased several measures of cadherin function. This suggests that the cadherin-activated c-Src signaling pathway serves positively to support cadherin function. Finally, our data implicate PI3-kinase signaling as a target for cadherin-activated c-Src signaling that contributes to its positive impact on cadherin function. We conclude that E-cadherin signaling is an important activator of c-Src at cell-cell contacts, providing a key input into a signaling pathway where quantitative changes in signal strength may result in qualitative differences in functional outcome.


Asunto(s)
Cadherinas/metabolismo , Comunicación Celular , Proteínas Proto-Oncogénicas pp60(c-src)/metabolismo , Transducción de Señal , Animales , Células CHO , Adhesión Celular , Línea Celular Tumoral , Cricetinae , Cricetulus , Activación Enzimática , Humanos , Fosfatidilinositol 3-Quinasas/metabolismo
19.
J Cell Sci ; 119(Pt 13): 2715-26, 2006 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-16757518

RESUMEN

Tuba is a multidomain scaffolding protein that links cytoskeletal dynamics and membrane trafficking pathways. The N-terminus of Tuba binds dynamin1, and the C-terminus contains domains that can interact with signaling pathways and cytoskeletal regulatory elements. We investigated Tuba localization, distribution and function in B16 melanoma cells. Tuba overexpression stimulated dorsal ruffles that occurred independently of dynamin function. Tuba expression induced actin-driven motility of small puncta that required the C-terminal SH3, GEF and BAR domains. Additionally, Tuba was recruited to lipid vesicles generated by overexpression of phosphatidylinositol-4-phosphate 5-kinase type Ialpha (PIP5Kalpha), localizing prominently to the head of the comets and at lower levels along the actin tail. We propose that Tuba facilitates dorsal ruffling of melanoma cells through direct interaction with actin-regulatory proteins and the recruitment of signaling molecules to lipid microdomains for the coordinated assembly of a cytoskeletal network. Knockdown of Tuba by RNA interference (RNAi) attenuated PIP5Kalpha-generated comet formation and the invasive behavior of B16 cells, implying that Tuba function is required for certain aspects of these processes. These results suggest first that Tuba-stimulated dorsal ruffling might represent a novel mechanism for the coordination of N-WASP-dependent cytoskeletal rearrangements and second that Tuba function is implicated in motility processes.


Asunto(s)
Actinas/metabolismo , Tubulina (Proteína)/metabolismo , Proteína Neuronal del Síndrome de Wiskott-Aldrich/metabolismo , Complejo 2-3 Proteico Relacionado con la Actina/metabolismo , Animales , Proteínas Portadoras/metabolismo , Moléculas de Adhesión Celular/metabolismo , Membrana Celular/metabolismo , Membrana Celular/ultraestructura , Estructuras de la Membrana Celular , Movimiento Celular , Células Cultivadas , Cortactina/metabolismo , Proteínas del Citoesqueleto , Fibronectinas/metabolismo , Silenciador del Gen , Sustancias de Crecimiento/farmacología , Melanoma Experimental , Ratones , Antígenos de Histocompatibilidad Menor , Invasividad Neoplásica , Fosfotransferasas (Aceptor de Grupo Alcohol)/metabolismo , Isoformas de Proteínas/metabolismo , Estructura Terciaria de Proteína , ARN Interferente Pequeño/metabolismo , Distribución Tisular , Transfección , Proteína de Unión al GTP cdc42/metabolismo
20.
Physiol Behav ; 88(4-5): 371-81, 2006 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-16725163

RESUMEN

(-)-Hydroxycitrate (HCA) might promote weight maintenance by limiting the capacity for de novo lipogenesis (DNL). It was investigated whether HCA may reduce DNL in humans during a persistent excess of energy intake as carbohydrate. In a double-blind, placebo-controlled, randomized and cross-over design, 10 sedentary lean male subjects (mean+/-S.D., age: 24+/-5 years, BMI: 21.8+/-2.1 kg/m2) performed a glycogen depletion exercise test followed by a 3-day high-fat diet (F/CHO/P, 60/25/15% energy; 100% of energy expenditure (EE)) and a 7-day high-CHO diet (F/CHO/P, <5/>85/10% energy; 130-175% of EE; overfeeding). During overfeeding, they ingested 3 x 500 mg/day HCA or placebo (PLA). Each intervention ended with a 60-h stay in the respiration chamber (days 9 and 10). Body weight increased during overfeeding (mean+/-S.E., HCA: 2.9+/-0.2 kg, PLA: 2.8+/-0.2 kg). Respiratory quotient (RQ) was >1.00 in all subjects indicating that DNL was present. On day 9, 24-h EE was lower with HCA compared to PLA (P < 0.05). On day 10, resting metabolic rate and RQ during night were lower (P < 0.01 and P < 0.05, respectively). Non-protein RQ, fat balance and net fat synthesis as DNL tended to be lower (P < 0.1) with HCA compared to PLA indicating lower DNL; activity-induced EE was higher with HCA (P < 0.05) indicating the urge to eliminate the excess of energy ingested. We conclude that an experimental condition resulting in DNL in humans was created and that treatment with HCA during overfeeding with carbohydrates may reduce DNL.


Asunto(s)
Citratos/farmacología , Metabolismo de los Lípidos/efectos de los fármacos , Lípidos/biosíntesis , Adulto , Afecto/efectos de los fármacos , Antropometría , Actitud , Composición Corporal/efectos de los fármacos , Peso Corporal , Calorimetría Indirecta , Estudios Cruzados , Carbohidratos de la Dieta/farmacología , Método Doble Ciego , Metabolismo Energético/efectos de los fármacos , Ejercicio Físico/fisiología , Glucógeno/metabolismo , Humanos , Masculino , Oxidación-Reducción , Mecánica Respiratoria/fisiología
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