Nanobiosensors based on individual olfactory receptors

In the SPOT-NOSED European project, nanoscale sensing elements bearing olfactory receptors and grafted onto functionalized gold substrates are used as odorant detectors to develop a new concept of nanobioelectronic nose, through sensitive impedancemetric measurement of single receptor conformational change upon ligand binding, with a better specificity and lower detection threshold than traditional physical sensors.Comment: Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/EDA-Publishing

Signaling of Human Frizzled Receptors to the Mating Pathway in Yeast

Frizzled receptors have seven membrane-spanning helices and are considered as atypical G protein-coupled receptors (GPCRs). The mating response of the yeast Saccharomyces cerevisiae is mediated by a GPCR signaling system and this model organism has been used extensively in the past to study mammalian GPCR function. We show here that human Frizzled receptors (Fz1 and Fz2) can be properly targeted to the yeast plasma membrane, and that they stimulate the yeast mating pathway in the absence of added Wnt ligands, as evidenced by cell cycle arrest in G1 and reporter gene expression dependent on the mating pathway-activated FUS1 gene. Introducing intracellular portions of Frizzled receptors into the Ste2p backbone resulted in the generation of constitutively active receptor chimeras that retained mating factor responsiveness. Introducing intracellular portions of Ste2p into the Frizzled receptor backbone was found to strongly enhance mating pathway activation as compared to the native Frizzleds, likely by facilitating interaction with the yeast Gα protein Gpa1p. Furthermore, we show reversibility of the highly penetrant G1-phase arrests exerted by the receptor chimeras by deletion of the mating pathway effector FAR1. Our data demonstrate that Frizzled receptors can functionally replace mating factor receptors in yeast and offer an experimental system to study modulators of Frizzled receptors

Comparative effects of cryosolvents on tubulin association, thermal stability, and binding of microtubule-associated proteins

International audienc

Biblio : application a la bibliographie d'un logiciel de gestion de bases de donnees

National audienc

Effect of organic cryosolvents on actin structures and actin/[MATH]-actinin binding geometries

Cryopreservation procedures of living cells involve the use of organic solvents against freezing damage. An efficient cryoprotection might be achieved by obtaining a cytoplasmic gel able to reduce water flux and avoid crystallization. Small angle X-ray scattering experiments were performed at LURE (Orsay, France) to investigate the effects of 1,2- propanediol and glycerol on the structure of actin, a major cytoplasmic protein, and on the binding geometries of actin to [MATH]-actinin, an interconnecting protein. In the presence of 1,2-propanediol, monomeric G-actin exhibits oligomerization into short rod-like structures very close to that of salt-polymerized actin filaments (F-actin). In the presence of [MATH]-actinin. F-actin filaments aggregate into thick and tight bundles. The scattering pattern in the presence of propanediol suggests a "ladder-like" structure with a tilt angle of the [MATH]-actinin molecule relative to F-actin filaments. This angle is even larger with glycerol. The resulting loose structures favor the formation of a microporous network. All these results support previous electron microscopy observations and the structural mechanisms deduced from rheological measurements

Effect of organic cryosolvents on actin structures and actin / alpha-actinin binding geometrics

International audienc

The effect of organic cryosolvents on actin structure : studies by small angle X-ray scattering

48 ref.International audienc

Rheological measurements of the influence of 1,2-propanediol on actin/alpha-actinin gel structure : the effects of temperature and protein concentrations

50 ref.International audienc

Régulations moléculaires de l'expression des récepteurs des gonadotropines

National audienc