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PDBsum entry 2x0c
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Cell adhesion
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PDB id
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2x0c
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References listed in PDB file
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Key reference
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Title
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Central region of talin has a unique fold that binds vinculin and actin.
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Authors
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A.R.Gingras,
N.Bate,
B.T.Goult,
B.Patel,
P.M.Kopp,
J.Emsley,
I.L.Barsukov,
G.C.Roberts,
D.R.Critchley.
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Ref.
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J Biol Chem, 2010,
285,
29577-29587.
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PubMed id
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Abstract
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Talin is an adaptor protein that couples integrins to F-actin. Structural
studies show that the N-terminal talin head contains an atypical FERM domain
while the N- and C-terminal parts of the talin rod comprise a series of
alpha-helical bundles. However, determining the structure of the central part of
the rod has proved problematic. Residues 1359-1659 are homologous to the MESDc1
gene product, and we therefore expressed this region of talin in E. coli. The
crystal structure shows a unique fold comprised of a 5- and 4-helix bundle. The
5-helix bundle is composed of non-sequential helices due to insertion of the
4-helix bundle into the loop at the C-terminus of helix alpha3. The linker
connecting the bundles forms a two-stranded anti-parallel beta-sheet likely
limiting the relative movement of the two bundles. Because the 5-helix bundle
contains the N- and C-termini of this module, we propose that it is linked by
short loops to adjacent bundles while the 4-helix bundle protrudes from the rod.
This suggests the 4-helix bundle has a unique role, and its pI (7.8) is higher
than other rod domains. Both helical bundles contain vinculin-binding sites, but
that in the isolated 5-helix bundle is cryptic whereas that in the isolated
4-helix bundle is constitutively active. In contrast, both bundles are required
for actin binding. Finally, we show that the MESDc1 protein, which is predicted
to have a similar fold, is a novel actin binding protein.
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