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PDBsum entry 2j59
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Contents |
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(+ 0 more)
165 a.a.
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(+ 0 more)
113 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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Structural basis for arf1-Mediated recruitment of arhgap21 to golgi membranes.
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Authors
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J.Ménétrey,
M.Perderiset,
J.Cicolari,
T.Dubois,
N.Elkhatib,
F.El khadali,
M.Franco,
P.Chavrier,
A.Houdusse.
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Ref.
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EMBO J, 2007,
26,
1953-1962.
[DOI no: ]
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PubMed id
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Abstract
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ARHGAP21 is a Rho family GTPase-activating protein (RhoGAP) that controls the
Arp2/3 complex and F-actin dynamics at the Golgi complex by regulating the
activity of the small GTPase Cdc42. ARHGAP21 is recruited to the Golgi by
binding to another small GTPase, ARF1. Here, we present the crystal structure of
the activated GTP-bound form of ARF1 in a complex with the Arf-binding domain
(ArfBD) of ARHGAP21 at 2.1 A resolution. We show that ArfBD comprises a PH
domain adjoining a C-terminal alpha helix, and that ARF1 interacts with both of
these structural motifs through its switch regions and triggers structural
rearrangement of the PH domain. We used site-directed mutagenesis to confirm
that both the PH domain and the helical motif are essential for the binding of
ArfBD to ARF1 and for its recruitment to the Golgi. Our data demonstrate that
two well-known small GTPase-binding motifs, the PH domain and the alpha helical
motif, can combine to create a novel mode of binding to Arfs.
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Figure 1.
Figure 1 Structure of the ARF1:ArfBD complex. (A) A cartoon
diagram of the ARF1:ArfBD complex is shown in two distinct
orientations. ARF1 is shown in grey with the  1
helix and switch I region in light and dark blue, respectively,
the interswitch region in green and the switch II region in red.
The Mg.GTP ligand is shown as a grey stick model. ArfBD is shown
in white with its  5'
region ( 5'
strand plus 5'–
6'
loop) in pink, the 1'
helix in orange and the Cter
helix in yellow. Tyr999 and Ile1053 of ArfBD are shown as stick
models. The two adjacent contact areas of the ARF1:ArfBD complex
interface are delineated by black boxes on the right-hand view.
(B) Detailed view of the interface between the Cter
helix and the PH domain of ArfBD. (C–F) Detailed views of the
ARF1:ArfBD interface. The secondary structures are shown as
ribbons and the residues as sticks. Hydrogen bonds are indicated
by dashed lines. (C) The 5'
region of ArfBD (pink) lies between the interswitch (green) and
switch I (blue) regions of ARF1 centred on Tyr999. (D) The
network of water-mediated interactions made between Asp996 of
the 5'
region (in pink) of ArfBD and ARF1. (E) The switch I (blue)
region of ARF1 interacts with the 5'
region (pink) and the 1'
helix (orange) of ArfBD. (F) The Cter
helix (yellow) of ArfBD is grasped between the switch II (red)
and the interswitch/switch I (green/blue) regions of ARF1.
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Figure 2.
Figure 2 The hydrophobic pocket and triad patch of Arf proteins.
(A) Front-view of the ARF1 hydrophobic pocket (transparent grey
area) and the hydrophobic triad patch (transparent purple area)
with the hydrophobic residue side chains shown as stick models.
(B) Sequence alignment of the Arf proteins (nomenclature from
Kahn et al, 2006) with residues of the hydrophobic pocket
indicated with grey shading and those of the triad patch
indicated in purple. Residues conserved with ARF1 are shown in
bold.
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The above figures are
reprinted
by permission from Macmillan Publishers Ltd:
EMBO J
(2007,
26,
1953-1962)
copyright 2007.
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Secondary reference #1
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Title
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Improving diffraction from 3a to 2a for a complex between a small gtpase and its effector by analysis of crystal contacts and use of reverse screening.
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Authors
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J.Menetrey,
M.Perderiset,
J.Cicolari,
A.Houdusse,
E.A.Stura.
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Ref.
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cryst growth des, 2007,
7,
2140.
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