Reversed mammalian protein-protein interaction trap

Abstract

The present invention relates to a recombinant receptor, comprising a ligand-binding domain and a signaling domain that comprises a heterologous bait polypeptide, which receptor is inactivated by binding of a prey polypeptide to the heterologous bait peptide, either in presence or absence of a ligand binding to the ligand-binding domain. The receptor is activated by addition of a compound that disrupts the bait-prey interaction. The present invention also relates to a method of screening compounds that disrupt compound-compound-binding using the recombinant receptor.

Description

[0001] This application is a continuation of PCT International Patent Application No. PCT / EP02 / 07419, filed on Jul. 2, 2002, designating the United States of America, and published, in English, as PCT International Publication No. WO 03 / 004643 A2 on Jan. 16, 2003, the contents of the entirety of which is incorporated by this reference.[0002] The present invention relates generally to biotechnology, and more particularly to a recombinant receptor comprising a ligand-binding domain and a signaling domain that comprises a heterologous bait polypeptide, which receptor is inactivated by binding of a prey polypeptide to the heterologous bait peptide, either in presence or absence of a ligand binding to the ligand-binding domain. The receptor is activated by addition of a compound that disrupts the bait-prey interaction. The present invention also relates to a method of screening compounds that disrupt compound-compound binding using the recombinant receptor.[0003] Protein-protein interact...

AI Technical Summary

Benefits of technology

[0021] In the case where disruptions of interactions of nuclear proteins are studied, the prey polypeptide may comprise a Nuclear Export Sequence (NES) to ensure that it is available in the cytosol. The NES signal (amino acids 37-46) of the heat-stable inhibitor of the cAMP-dependent protein kinase has been shown to override a strong nuclear localization signal (Wiley et al., 1999). This NES will keep the prey polypeptide in the cytoplasm even if it has a strong nuclear localization signal, facilitating the interaction with the bait.

[0025] Still another aspect of the invention is a kit comprising one or more cloning vectors allowing the construction of one or more vectors according to the invention. It is clear for the people skilled in the art that a cloning vector encoding a recombinant receptor in which the part encoding for the cytoplasmic domain comprises one or more restriction sites, allowing an "in frame" fusion of a nucleic acid fragment encoding a polypeptide, can easily be used to construct a vector encoding a recombinant receptor according to the invention. In a similar way, a cloning vector encoding a first polypeptide comprising at least one inhibiting domain and / or a recruitment site for an inhibitor, such as a SOCS or SHP recruitment site, comprising one or more restriction sites allowing an "in frame" fusion of a nucleic acid encoding a second polypeptide with the first polypeptide can easily be used to construct a vector encoding a prey polypeptide according to the invention. Alternatively, both for the construction of the vector encoding the recombinant receptor and for the vector encoding the prey polypeptide, other cloning strategies known to the person skilled in the art may be used.

[0029] FIG. 1: Principle of the reversed mammalian protein-protein interaction trap. B: bait; K: modifying enzyme activity; L: ligand; M: possible modification of the bait; P: prey. F and Y represent the amino acids that function as a mutated (F) or functional (Y) receptor activation site or inhibitor recruitment site. The example illustrates a tyrosine phosphorylation site. As is shown in the figure, the bait-prey interaction may be modification dependent. The inhibitor, such as SOCS or a functional part thereof, is fused to the prey polypeptide, as illustrated at the left-hand side. Alternatively, an inhibitor recruitment domain, such as a SOCS or SHP recruitment domain, may be fused to the prey, as illustrated at the right-hand side. Both domains may be connected by a hinge region, such as a GGS sequence, to optimize the flexibility of the protein and the resulting negative feedback. The prey polypeptide may be fused to a "flag" sequence to facilitate identification and / or isolation, but this is not an essential feature.

Problems solved by technology

Preferably, the inhibitor may inhibit directly the modifying enzyme activity that is activating the activation site of the receptor, or it may bind to the activation site and block the modification of the site, or it may remove the modification from the activation site, or it may change the conformation of either the modifying enzyme or of the activation site, making a modification impossible.

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