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PDBsum entry 2cia
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References listed in PDB file
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Key reference
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Title
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The phosphotyrosine peptide binding specificity of nck1 and nck2 src homology 2 domains.
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Authors
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S.Frese,
W.D.Schubert,
A.C.Findeis,
T.Marquardt,
Y.S.Roske,
T.E.Stradal,
D.W.Heinz.
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Ref.
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J Biol Chem, 2006,
281,
18236-18245.
[DOI no: ]
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PubMed id
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Abstract
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Nck proteins are essential Src homology (SH) 2 and SH3 domain-bearing adapters
that modulate actin cytoskeleton dynamics by linking proline-rich effector
molecules to tyrosine kinases or phosphorylated signaling intermediates. Two
mammalian pathogens, enteropathogenic Escherichia coli and vaccinia virus,
exploit Nck as part of their infection strategy. Conflicting data indicate
potential differences in the recognition specificities of the SH2 domains of the
isoproteins Nck1 (Nckalpha) and Nck2 (Nckbeta and Grb4). We have characterized
the binding specificities of both SH2 domains and find them to be essentially
indistinguishable. Crystal structures of both domains in complex with
phosphopeptides derived from the enteropathogenic E. coli protein Tir concur in
identifying highly conserved, specific recognition of the phosphopeptide.
Differential peptide recognition can therefore not account for the preference of
either Nck in particular signaling pathways. Binding studies using sequentially
mutated, high affinity phosphopeptides establish the sequence variability
tolerated in peptide recognition. Based on this binding motif, we identify
potential new binding partners of Nck1 and Nck2 and confirm this experimentally
for the Arf-GAP GIT1.
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Figure 2.
FIGURE 2. Phosphopeptide complexes of Nck1-SH2 and
Nck2-SH2. A, Nck1-SH2 binds Tir12 (yellow), a 12-residue peptide
from the EPEC virulence factor Tir. Two N-terminal glutamate
residues of the peptide, not resolved in the electron density,
are excluded. The electrostatic surface reveals a deep,
positively charged (blue) phosphotyrosine binding pocket. B,
Nck2-SH2 complexed to Tir8 (green). C, schematic representation
of the Nck-SH2/Tir interaction. Chemical bonds of Tir12 are
shown in black, and those of residues of Nck are shown in
orange. Hydrogen bonds are indicated by dashed lines,
hydrophobic interactions by green arcs, and a cation-  interaction
by a blue dashed line.
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Figure 3.
FIGURE 3. Nck1-SH2-Tir12 complex (shades of yellow)
superimposed on Nck2-SH2/Tir8 (green). A, the interactions of
SH2 domain and peptide are conserved superimposing the peptides.
B, the 17 nonconserved residues between Nck1- and Nck2-SH2
(green spheres) are distributed over the SH2 surfaces away from
the peptide-protein interface.
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The above figures are
reprinted
by permission from the ASBMB:
J Biol Chem
(2006,
281,
18236-18245)
copyright 2006.
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