Method for identifying modulators of G protein coupled receptor signaling

Abstract

This invention relates to methods for identifying peptides and other compounds which block or enhance G protein coupled receptor mediated signaling with high affinity and specificity and / or which stabilize a particular conformer of a G protein coupled receptor. Assays, methods of treatment and other methods developed in conjunction with these methods also are disclosed.

Description

[0001] This application is a continuation of application Ser. No. 10 / 411,336, filed Apr. 11, 2003, which is a continuation-in-part of prior co-pending application Ser. No. 09 / 852,910, filed May 11, 2001, which claims priority from prior co-pending provisional application Ser. No. 60 / 275,472, filed Mar. 14, 2001.BACKGROUND OF THE INVENTION [0002] 1. Technical Field [0003] The present invention generally pertains to the field of modulating activity of G protein-coupled receptors (GPCR) and of identifying and preparing G protein coupled receptor antagonist and agonist compounds, including direct, indirect, full, partial, inverse and allosteric agonists. The invention also encompasses compounds that bind to GPCR to stabilize a particular conformation of the GPCR. These compounds can serve as lead compounds for drug discovery purposes or for studying the GPCR three dimensional structure of specific conformations by such methods as X-ray crystallography or NMR. The invention also relates ...

AI Technical Summary

Benefits of technology

[0037] Accordingly, the invention provides a method of identifying a G protein coupled receptor signaling modifying peptide, which comprises providing a peptide library based on a native G protein coupled receptor binding peptide; screening the peptide library for high affinity binding to the G protein coupled receptor; and selecting a member of the peptide library having binding to the G protein coupled receptor of higher affinity than that of the native peptide. The screening may be performed by testing for binding to an intact G protein coupled receptor or to at least an intracellular fragment of a G protein coupled receptor.

Problems solved by technology

Some persons report consistent difficulties in seeing at night, even when their eyes are fully dark-adapted.

They cannot detect objects readily visible to others and show both confusion and slow recovery after brief exposure to relatively bright light sources.

Maneuvering in dimly illuminated spaces and driving or flying at night present serious problems to these individuals.

No definitive data on the occurrence of nyctalopia in the population are available, since measurements have never been made on a representative sample of the population.

However, the night blindness associated with visual diseases such as retinitis pigmentosa (RP), cataracts, diabetic retinopathy, and glaucoma is only somewhat helped with vitamin A supplements, which do not change the course of the disease.

On the other hand, receptor subtype-selective drugs have been difficult to obtain.

An additional drawback to the classical approach of designing drugs to interfere with ligand binding has been that conventional antagonists are ineffective for some GPCRs such as proteinase activated receptors (PAR) due to the unique mechanism of enzymatic cleavage of the receptor and generation of a tethered ligand.

In other cases, intrinsic or constitutive activity of receptors leads to pathology directly, thus rendering antagonism of ligand binding moot.

Drug discovery approaches which take advantage of this phenomenon, however, are not available.

Drug discovery approaches which take advantage of this opportunity, however, are not available.

One of the major challenges confronting those using these types of methods is the difficulty of identifying useful binding compounds from very large combinatorial libraries of potential candidate molecules.

When literally hundreds of thousands of compounds are screened, characterizing the compounds which test positive for binding, for modulatory activity or for stabilization of a conformation (including false positives) is an expensive and time-consuming process.

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