TY - JOUR
T1 - A Phosphorylation-Dependent Gating Mechanism Controls the SH2 Domain Interactions of the Shc Adaptor Protein
AU - George, Roger
AU - Schuller, Annika C.
AU - Harris, Richard
AU - Ladbury, John E.
PY - 2008/3/28
Y1 - 2008/3/28
N2 - The Shc (Src homology collagen-like) adaptor protein plays a crucial role in linking stimulated receptors to mitogen-activated protein kinase activation through the formation of dynamic signalling complexes. Shc comprises an N-terminal phosphotyrosine binding (PTB) domain, a C-terminal Src homology 2 (SH2) domain and a central proline-rich collagen homology 1 domain. The latter domain contains three tyrosine residues that are known to become phosphorylated. We have expressed and purified the human p52Shc isoform and characterised its binding to different ligands. CD spectra revealed that some parts of the Shc protein are not fully folded, remaining largely unaffected by the binding of ligands. The PTB domain binds peptide and Ins-1,4,5-P3 (but not Ins-1,3,5-P3) independently, suggesting two distinct sites of interaction. In the unphosphorylated Shc, the SH2 domain is non-functional. Ligand binding to the PTB domain does not affect this. However, phosphorylation of the three tyrosine residues promotes binding to the SH2 domain. Thus, Shc has an intrinsic phosphorylation-dependent gating mechanism where the SH2 domain adopts an open conformation only when tyrosine phosphorylation has occurred.
AB - The Shc (Src homology collagen-like) adaptor protein plays a crucial role in linking stimulated receptors to mitogen-activated protein kinase activation through the formation of dynamic signalling complexes. Shc comprises an N-terminal phosphotyrosine binding (PTB) domain, a C-terminal Src homology 2 (SH2) domain and a central proline-rich collagen homology 1 domain. The latter domain contains three tyrosine residues that are known to become phosphorylated. We have expressed and purified the human p52Shc isoform and characterised its binding to different ligands. CD spectra revealed that some parts of the Shc protein are not fully folded, remaining largely unaffected by the binding of ligands. The PTB domain binds peptide and Ins-1,4,5-P3 (but not Ins-1,3,5-P3) independently, suggesting two distinct sites of interaction. In the unphosphorylated Shc, the SH2 domain is non-functional. Ligand binding to the PTB domain does not affect this. However, phosphorylation of the three tyrosine residues promotes binding to the SH2 domain. Thus, Shc has an intrinsic phosphorylation-dependent gating mechanism where the SH2 domain adopts an open conformation only when tyrosine phosphorylation has occurred.
KW - isothermal titration calorimetry
KW - protein complex
KW - protein-ligand interactions
KW - tyrosine kinase signalling
KW - tyrosyl phosphopeptide
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U2 - 10.1016/j.jmb.2007.12.040
DO - 10.1016/j.jmb.2007.12.040
M3 - Article
C2 - 18279888
AN - SCOPUS:40649128513
SN - 0022-2836
VL - 377
SP - 740
EP - 747
JO - Journal of Molecular Biology
JF - Journal of Molecular Biology
IS - 3
ER -