Abstract: The instant invention provides for methods for detecting the internalization of a transmembrane protein of interest expressed at the surface of a cell. More specifically, the methods involve (a) labelling the protein of interest with a fluorescent metal complex, the lifetime of which is greater than 0.1 ms, (b) adding to the reaction medium a composition capable of causing the internalization of the protein of interest, (c) adding to the reaction medium (1) a modulating agent which is a fluorescent FRET acceptor compound compatible with the fluorescent metal complex, the final concentration of which in the reaction medium is greater than 10?7M; or (2) a reducing agent, the redox potential of which is less than +0.1 V and preferably between 0.25 and 0.

Abstract: The present invention relates to inositol phosphate derivatives, in which the inositol phosphate is substituted with one or two reactive groups G or one or two conjugated substances or molecules M, said reactive group(s) G or said substance(s) or molecule(s) M being linked to IP1 via a linkage group L, M being chosen from the following group: a tracer, an immunogen, a member of a binding partner pair, a solid support. Application: tools allowing the study of the inositol phosphate cycle and therefore, indirectly, the study of seven transmembrane domain receptors coupled to phospholipase C, receptors having a tyrosine kinase activity, and in general enzymes involved in the variations of the intracellular concentration of IP1.

Abstract: A method for detecting the internalization of a transmembrane protein of interest expressed at the surface of a cell, comprising the following steps: a) labelling the protein of interest with a fluorescent metal complex, the lifetime of which is greater than 0.1 ms; b) adding to the reaction medium a composition capable of causing the internalization of the protein of interest; c) adding to the reaction medium a modulating agent selected from: a. a fluorescent or nonfluorescent FRET acceptor compound compatible with said fluorescent metal complex, the final concentration of which in the reaction medium is greater than 10?7M; b. a reducing agent, the redox potential of which is less than +0.1 V and preferably between 0.25 and 0.75 V; c. an agent which binds specifically, by noncovalent bonding, with the fluorescent metal complex; d.

Abstract: The present invention relates to a method of revealing a biological process using a FRET measurement, which comprises the following steps: incorporating, into a measurement medium containing a lipid membrane, a biological entity X coupled with a first member of a pair of FRET partners and a second biological entity Y coupled with the second member of the pair of FRET partners, the energy-donating member of the pair of FRET partners having a long lifetime and the members of said pair of FRET partners being located on either side of the lipid membrane; exciting the measurement medium at the excitation wavelength of the energy-donating member; and measuring the FRET signal or the variations in said signal emitted in said culture medium.

Abstract: The present invention relates to a method of revealing a biological process using a FRET measurement, which comprises the following steps: incorporating, into a measurement medium containing a lipid membrane, a biological entity X coupled with a first member of a pair of FRET partners and a second biological entity Y coupled with the second member of the pair of FRET partners, the energy-donating member of the pair of FRET partners having a long lifetime and the members of said pair of FRET partners being located on either side of the lipid membrane; exciting the measurement medium at the excitation wavelength of the energy-donating member; and measuring the FRET signal or the variations in said signal emitted in said culture medium.

Abstract: The present invention relates to inositol phosphate derivatives, in which the inositol phosphate is substituted with one or two reactive groups G or one or two conjugated substances or molecules M, said reactive group(s) G or said substance(s) or molecule(s) M being linked to IP1 via a linkage group L, M being chosen from the following group: a tracer, an immunogen, a member of a binding partner pair, a solid support. Application: tools allowing the study of the inositol phosphate cycle and therefore, indirectly, the study of seven transmembrane domain receptors coupled to phospholipase C, receptors having a tyrosine kinase activity, and in general enzymes involved in the variations of the intracellular concentration of IP1.

Abstract: The present invention relates to a method for the detection of ligands (agonists or antagonists) specific for a G protein-coupled receptor (GPCR), which comprises the steps consisting in: 1) bringing a receptor labelled with a member of a donor/acceptor pair into contact with a G? or G?? subunit of a G protein labelled with the other member of the donor/acceptor pair; 2) measuring the transfer by proximity effect between the donor and the acceptor.