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PDBsum entry 1z2c
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Signaling protein
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PDB id
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1z2c
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References listed in PDB file
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Key reference
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Title
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Structural and mechanistic insights into the interaction between rho and mammalian dia.
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Authors
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R.Rose,
M.Weyand,
M.Lammers,
T.Ishizaki,
M.R.Ahmadian,
A.Wittinghofer.
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Ref.
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Nature, 2005,
435,
513-518.
[DOI no: ]
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PubMed id
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Abstract
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Formins are involved in a variety of cellular processes that require the
remodelling of the cytoskeleton. They contain formin homology domains FH1 and
FH2, which initiate actin assembly. The Diaphanous-related formins form a
subgroup that is characterized by an amino-terminal Rho GTPase-binding domain
(GBD) and an FH3 domain, which bind somehow to the carboxy-terminal Diaphanous
autoregulatory domain (DAD) to keep the protein in an inactive conformation.
Upon binding of activated Rho proteins, the DAD is released and the ability of
the formin to nucleate and elongate unbranched actin filaments is induced. Here
we present the crystal structure of RhoC in complex with the regulatory N
terminus of mammalian Diaphanous 1 (mDia1) containing the GBD/FH3 region, an
all-helical structure with armadillo repeats. Rho uses its 'switch' regions for
interacting with two subdomains of GBD/FH3. We show that the FH3 domain of mDia1
forms a stable dimer and we also identify the DAD-binding site. Although binding
of Rho and DAD on the N-terminal fragment of mDia1 are mutually exclusive, their
binding sites are only partially overlapping. On the basis of our results, we
propose a structural model for the regulation of mDia1 by Rho and DAD.
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Figure 3.
Figure 3: The Rho -mDia[N] interaction. a, Stereo diagram of
the Rho -mDia[N] interface. Colour-coding of mDia[N] as in Fig.
2a, Rho in yellow, and switch regions of Rho in red. Residues
involved in the interface (cutoff level 3.6 Å) are shown in
ball-and-stick configuration. b, Schematic drawing of
interacting residues in Rho and mDia. c, Superimposition of the
Rho -mDia[N] complex (yellow) with RhoA  GDP
(red)27 (Protein Data Bank entry 1DPF). d, Superimposition of
the Rho -mDia[N] complex with Cdc42 GppNHp
(ref. 30, Protein Data Bank entry 1AM4). e, Van der Waals
surface representation of mDia[N] (upper) and RhoC GppNHp
(lower). Left panels show residues that are 100% conserved
between RhoA, B, C, Cdc42 and Rac1 (black, lower panel), or >75%
(blue) or >50% (magenta) conserved between mDia1, 2, 3 and human
Dia1 -3 (upper panel). Residues of Rho and mDia involved in
forming the Rho -mDia interface are shown in red in right panels.
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Figure 4.
Figure 4: Mutually exclusive binding of Rho and DAD to mDia[N].
a, b, Observed association rate constants for the binding of
wild-type and mutant RhoA to wild-type mDia[N] (a) or wild-type
RhoA to different mDia[N] mutants (b), measured as in Fig. 1. c,
d, Fluorescence polarization assay with 1 µM AMCA-labelled DAD
peptide, mDia[N] mutants A256D (c) and N165D (d) and RhoA as
described in Fig. 2. In c, wild-type mDia[N] was added as a
control, to show DAD binding ability. All experiments were
repeated at least twice and typical experiments are shown. e,
Schematic diagram of the partially overlapping binding sites
identified here and the proposed mechanism of release of
DAD-mediated autoinhibition by Rho, as discussed in the text.
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The above figures are
reprinted
by permission from Macmillan Publishers Ltd:
Nature
(2005,
435,
513-518)
copyright 2005.
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Secondary reference #1
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Title
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The purification and crystallisation of mdia1 in complex with rhoc
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Authors
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R.Rose,
A.Wittinghofer,
M.Weyand.
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Ref.
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acta crystallogr , sect f, 2005,
61,
225.
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