Abstract
To determine whether individual autophosphorylation sites in the epidermal growth factor (EGF) receptor define specific interaction sites for the in vivo association of signal transduction proteins that contain src homology 2 (SH2) domains, the capacity of wild-type and mutant EGF receptors to associate with several SH2 domain-containing proteins has been assayed. Mutants included receptors with single autophosphorylation site mutations at each of five autophosphorylation sites and receptors in which multiple autophosphorylation sites were removed by point mutation or deletion of carboxyl-terminal residues. Receptor association, as measured by coimmunoprecipitation, has been determined for phospholipase C-gamma 1, the ras GTPase-activating protein, the p85 subunit of phosphatidylinositol 3-kinase, and the src homology and collagen protein. In contrast to data obtained with single autophosphorylation site mutants of other receptor tyrosine kinases, none of the EGF receptor single site mutants was dramatically impaired in its capacity to associate with any of these SH2-containing proteins. However, association was completely abrogated when all five autophosphorylation sites were mutated or removed by deletion. These results indicate that individual autophosphorylation sites in the EGF receptor are not stringently required for the recognition and association of different SH2-containing substrates. Thus, EGF receptor autophosphorylation sites seem to be flexible and/or compensatory in their capacity to mediate association with these four SH2-containing substrates.
Highlights
To determinewhetherindividualautophosphoryla- sequences within each SH2 domain, leads to high affinity astion sites in the epidermal growth factor (EGF) receptosorciation of activated receptors and SH2-containing molecules
Define specific interaction sites for the in vivo associa- While some SH2-containing molecules are used as phosphorytion of signal transduction proteins that contasirnc ho- lation substrates by receptor tyrosine kinases, others are not mology 2 (SH2) domains, the capacity of wild-type and phosphorylated, but function as adaptors to mediate complex mutant EGF receptors to associate with severalSH2 do- formation between receptors and other cellularproteins
Other receptor tyrosinke inases, none of the EGF recep- The basis of the interaction between SH2-containing protor single site mutants was dramatically impairedin its teins and receptor tyrosine kinases has been most extensively capacity to associate with any of these SH2-containing studied with autophosphorylation site mutantosf the plateletproteins.association wascompletelyabrogated when allfive autophosphorylationsites were mutated or removebdy deletion.These results indicate that individual autophosphorylationsites in the EGF receptor are not stringently required fotrhe recognition and association of differenStH2-containinsgubstrates
Summary
To determinewhetherindividualautophosphoryla- sequences within each SH2 domain, leads to high affinity astion sites in the epidermal growth factor (EGF) receptosorciation of activated receptors and SH2-containing molecules. Quantitation of association of SH2-containing substrates withEGF receptor single autophosphorylation site mutants
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have