Search results for "Transduction"

Mosaic activating mutations in GNA11 and GNAQ are associated with phakomatosis pigmentovascularis and extensive dermal melanocytosis

2016

Common birthmarks can be an indicator of underlying genetic disease but are often overlooked. Mongolian blue spots (dermal melanocytosis) are usually localized and transient, but they can be extensive, permanent, and associated with extracutaneous abnormalities. Co-occurrence with vascular birthmarks defines a subtype of phakomatosis pigmentovascularis, a group of syndromes associated with neurovascular, ophthalmological, overgrowth, and malignant complications. Here, we discover that extensive dermal melanocytosis and phakomatosis pigmentovascularis are associated with activating mutations in GNA11 and GNAQ, genes that encode Gα subunits of heterotrimeric G proteins. The mutations were det…

Why mammalian wound-healing researchers may wish to turn to Drosophila as a model.

2014

Wound healing is an essential and complex biological process that allows tissue continuity and functioning to be restored after injury. Understanding the molecular and cellular mechanisms underlying wound repair is essential to develop new therapies that could be useful not only to accelerate the normal healing process but also to treat healing pathologies that appear as a consequence of improper wound resolution. Numerous models have been developed to study wound healing both in vitro and in vivo. In vitro models have been useful to study some steps of epithelial repair. However, the development of effective treatments for wound healing is still required, and this could mainly be achieved …

Polar accumulation of the metabolic sensory histidine kinases DcuS and CitA in Escherichia coli

2008

Signal transduction in prokaryotes is frequently accomplished by two-component regulatory systems in which a histidine protein kinase is the sensory component. Many of these sensory kinases control metabolic processes that do not show an obvious requirement for inhomogeneous distribution within bacterial cells. Here, the sensory kinases DcuS and CitA, two histidine kinases of Escherichia coli, were investigated. Both are membrane-integral and involved in the regulation of carboxylate metabolism. The two-component sensors were fused with yellow fluorescent protein (YFP) and live images of immobilized cells were obtained by confocal laser fluorescence microscopy. The fluorescence of the fusio…

The evolution of nitric oxide signalling diverges between the animal and the green lineages

2019

AbstractNitric oxide (NO) is a ubiquitous signalling molecule with widespread distribution in prokaryotes and eukaryotes where it is involved in countless physiological processes. While the mechanisms governing nitric oxide (NO) synthesis and signalling are well established in animals, the situation is less clear in the green lineage. Recent investigations have shown that NO synthase, the major enzymatic source for NO in animals, is absent in land plants but present in a limited number of algae. The first detailed analysis highlighted that these new NO synthases are functional but display specific structural features and probably original catalytic activities. Completing this picture, analy…

Relationships between Staphylococcus aureus genetic background, virulence factors, agr groups (alleles), and human disease

2002

ABSTRACT The expression of most Staphylococcus aureus virulence factors is controlled by the agr locus, which encodes a two-component signaling pathway whose activating ligand is an agr -encoded autoinducing peptide (AIP). A polymorphism in the amino acid sequence of the AIP and of its corresponding receptor divides S. aureus strains into four major groups. Within a given group, each strain produces a peptide that can activate the agr response in the other member strains, whereas the AIPs belonging to different groups are usually mutually inhibitory. We investigated a possible relationship between agr groups and human S. aureus disease by studying 198 S. aureus strains isolated from 14 asym…

Rapid odorant release in mammalian odour binding proteins facilitates their temporal coupling to odorant signals.

2010

 ; We have measured the effect of rat odorant-binding protein 1 on the rates of ligand uptake and liquid-to-air transfer rates with a set of defined odorous compounds. Comparison of observed rate constants (k(obs)) with data simulated over a wide range of different kinetic and thermodynamic regimes shows that the data do not agree with the previously held view of a slow off-rate regime (k(off) <0.0004 s(-1)). We propose that a rapid koff would be a necessary requirement for such a system, since slow odorant-release rates would result in significant decorrelation between the olfactory world and odour perception. (c) 2010 Elsevier Ltd. All rights reserved.

The membrane proteome of Medicago truncatula roots displays qualitative and quantitative changes in response to arbuscular mycorrhizal symbiosis

2014

International audience; Arbuscular mycorrhizal (AM) symbiosis that associates roots of most land plants with soil-borne fungi (Glomeromycota), is characterized by reciprocal nutritional benefits. Fungal colonization of plant roots induces massive changes in cortical cells where the fungus differentiates an arbuscule, which drives proliferation of the plasma membrane. Despite the recognized importance of membrane proteins in sustaining AM symbiosis, the root microsomal proteome elicited upon mycorrhiza still remains to be explored. In this study, we first examined the qualitative composition of the root membrane proteome of Medicago truncatula after microsome enrichment and subsequent in dep…

Les histones déacétylases de type 2 (HD2): des régulateurs importants de l'immunité innée chez le tabac

2013

Terminal tendon cell differentiation requires the glide/gcm complex.

2004

International audience; Locomotion relies on stable attachment of muscle fibres to their target sites, a process that allows for muscle contraction to generate movement. Here, we show that glide/gcm and glide2/gcm2, the fly glial cell determinants, are expressed in a subpopulation of embryonic tendon cells and required for their terminal differentiation. By using loss-of-function approaches, we show that in the absence of both genes, muscle attachment to tendon cells is altered, even though the molecular cascade induced by stripe, the tendon cell determinant, is normal. Moreover, we show that glide/gcm activates a new tendon cell gene independently of stripe. Finally, we show that segment p…

Effet de l'humidité sur la réponse à l'ammoniac de capteurs conductimétriques à base de matériaux moléculaires

2012

Many ammonia sensors are available but the consideration of the humidity effect is scarcely insured even by manufacturers. The aim of this thesis is to propose a conductimetric transducer capable tomeasure ammonia selectively, with enough accuracy for air quality control, in a variable humidity environment. To reach this goal, we used thin film resistors made of cobalt phthalocyanines as semiconductor. This study deals with thin films processing made by vacuum evaporation, solventcast and electrodeposition. Automated workbenches were developed to perform electrical measurements under argon and to study the response of sensors to dry or humid ammonia by meansof 1 min / 4 min-long exposure / …