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PDBsum entry 2ff6
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Structural protein/contractile protein
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PDB id
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2ff6
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Contents |
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125 a.a.
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11 a.a.
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360 a.a.
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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 structural basis of actin interaction with multiple wh2/beta-Thymosin motif-Containing proteins.
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Authors
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A.H.Aguda,
B.Xue,
E.Irobi,
T.Préat,
R.C.Robinson.
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Ref.
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Structure, 2006,
14,
469-476.
[DOI no: ]
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PubMed id
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Abstract
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Participation of actin in cellular processes relies on the dynamics of filament
assembly. Filament elongation is fed by monomeric actin in complex with either
profilin or a Wiscott-Aldrich syndrome protein (WASP) homology domain 2
(WH2)/beta-thymosin (betaT) domain. WH2/betaT motif repetition (typified by
ciboulot) or combination with nonrelated domains (as found in N-WASP) results in
proteins that yield their actin to filament elongation. Here, we report the
crystal structures of actin bound hybrid proteins, constructed between gelsolin
and WH2/betaT domains from ciboulot or N-WASP. We observe the C-terminal half of
ciboulot domain 2 bound to actin. In solution, we show that cibolout domains 2
and 3 bind to both G- and F-actin, and that whole ciboulot forms a complex with
two actin monomers. In contrast, the analogous portion of N-WASP WH2 domain 2 is
detached from actin, indicating that the C-terminal halves of the betaT and WH2
motifs are not functionally analogous.
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Figure 3.
Figure 3. Comparison of Actin Bound WH2/Tβ Domain
Superimposed Structures
(A) The WH2/Tβ chains are shown as
Cα traces, and the actin protomer is shown as a ribbon
representation (light blue). Cib2 is drawn in light green, Tβ4
(Irobi et al., 2004) is drawn in pink, Cib1 (Hertzog et al.,
2004) is drawn in purple, and N-WASP is drawn in black.
(B)
A 90° rotation of (A) around the vertical axis.
(C)
Comparison of the actin structures from G1-Cib23:actin (blue)
and G1-Nw2 (yellow) through superposition of subdomain 4.
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Figure 6.
Figure 6. Schematic Models of the Mechanism of F-Actin
Interaction with Tβ Proteins When Bound to More Than One Actin
Monomer
(A) Possible interactions with TTβ (black) and
actobindin (Act, purple). G-actin and F-actin protomers are
depicted in green and light blue, respectively.
(B)
Possible interactions of ciboulot (Cib, yellow) with actin. In
this mechanism, at the barbed end of the filament (+), the
N-terminal helices are proposed to be released by the actin G-
to –F-actin transition, while, at the pointed end (−), the
C-terminal cap is unaffected by the state of actin. Red crosses
signify capped filaments (Irobi et al., 2004).
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The above figures are
reprinted
by permission from Cell Press:
Structure
(2006,
14,
469-476)
copyright 2006.
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