METHOD FOR ASSAYING FOR A SUBSTANCE THAT AFFECTS AN SH2-PHOSPHORYLATED LIGAND REGULATORY SYSTEM

摘要

A method for assaying a medium for the presence of a substance that affects an SH2-phosphorylated ligand regulatory system. The method employs an SH2-like domain or a subdomain thereof and a phosphorylated ligand. The phosphophorylated ligand is capable of interacting with the SH2-like domain or a subdomain thereof to form an SH2- phosphorylated ligand complex. The SH2-like domain or subdomain and/or the phosphorylated ligand are present in a known concentration. The SH2-like domain or a subdomain thereof and the phosphorylated ligand are incubated with a substance which is suspected of affecting an SH2- phosphorylated ligand regulatory system. The method is carried out under conditions which permit the formation of the SH2-phosphorylated ligand complex. SH2-phosphorylated ligand complex, free SH2-like domain or subdomains thereof, or non-complexed phosphorylated ligand are assayed. The invention also relates to an isolated SH2- phosphorylated ligand complex; a method of using an isolated SH2-like domain or a subdomain thereof to screen for phosphorylated ligands which are active in an SH2- phosphorylated ligand regulatory system; a method of using an isolated SH2-like domain or a subdomain thereof to regulate the interaction of a signalling protein with a related phosphorylated ligand; and a pharmaceutical composition comprising an isolated SH2-like domain or a subdomain thereof for use as an agonist or antagonist of the interaction of a signalling protein with a related phosphorylated ligand.