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PDBsum entry 2qyf
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197 a.a.
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188 a.a.
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183 a.a.
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191 a.a.
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11 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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P31comet blocks mad2 activation through structural mimicry.
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Authors
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M.Yang,
B.Li,
D.R.Tomchick,
M.Machius,
J.Rizo,
H.Yu,
X.Luo.
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Ref.
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Cell, 2007,
131,
744-755.
[DOI no: ]
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PubMed id
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Abstract
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The status of spindle checkpoint signaling depends on the balance of two
opposing dynamic processes that regulate the highly unusual two-state behavior
of Mad2. In mitosis, a Mad1-Mad2 core complex recruits cytosolic Mad2 to
kinetochores through Mad2 dimerization and converts Mad2 to a conformer amenable
to Cdc20 binding, thereby facilitating checkpoint activation. p31(comet)
inactivates the checkpoint through binding to Mad1- or Cdc20-bound Mad2, thereby
preventing Mad2 activation and promoting the dissociation of the Mad2-Cdc20
complex. Here, we report the crystal structure of the Mad2-p31(comet) complex.
The C-terminal region of Mad2 that undergoes rearrangement in different Mad2
conformers is a major structural determinant for p31(comet) binding, explaining
the specificity of p31(comet) toward Mad1- or Cdc20-bound Mad2. p31(comet)
adopts a fold strikingly similar to that of Mad2 and binds at the dimerization
interface of Mad2. Thus, p31(comet) exploits the two-state behavior of Mad2 to
block its activation by acting as an "anti-Mad2."
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Figure 4.
Figure 4. Interactions between Mad2 and p31^comet
(A)
Ribbon diagrams of the Mad2-p31^comet complex. Two different
views are shown to provide a clearer perspective of the
Mad2-p31^comet interface. Helix αC in Mad2 is colored cyan to
highlight its central role in establishing interactions between
Mad2 and p31^comet. Three main patches of interactions at the
Mad2-p31^comet interface are labeled and circled with red dashed
lines.
(B–D) Interactions between Mad2 and p31^comet. The
side chains of contacting residues are shown as sticks. Nitrogen
and oxygen atoms are colored blue and red, respectively. Mad2
carbons are colored yellow and p31^comet carbons are colored
gray and labeled in italics. The tightly bound water molecules
are drawn as red spheres in (C).
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Figure 6.
Figure 6. A Structural Model for the Blockage of
Mad1-Assisted Mad2 Activation by p31^comet
(A) A structural
model of the Mad1-Mad2-p31^comet complex. The Mad2 molecule in
the Mad2-p31^comet complex was superimposed with the Mad2
molecules in the Mad1-Mad2 complex (PDB ID 1GO4). For clarity,
the Mad2 monomers in the Mad1-Mad2 complex are omitted. Mad1 is
colored green, with its Mad2-binding region colored red. The
three interacting helices in Mad2-p31^comet are indicated.
(B) A surface representation to show that C-Mad2 uses a similar
surface for the binding of p31^comet or O-Mad2. The
p31^comet-binding residues of C-Mad2 are colored yellow, and the
four key interacting residues, R133, Q134, R184 and F141, are
colored red. The O-Mad2-binding residues of C-Mad2 are colored
yellow. The same four residues R133, Q134, R184, and F141 (red)
that are important for p31^comet binding are also involved in
O-Mad2 binding.
(C) Ribbon diagram of the O-Mad2–C-Mad2
dimer (Mapelli et al., 2007). O-Mad2 is colored in cyan. C-Mad2
is colored blue with its C-terminal region shown in yellow. MBP1
is in red. The αC helices are labeled.
(D) Ribbon diagram
of the Mad2-p31^comet complex with C-Mad2 in the same
orientation as in (C).
(E) Overlay of ribbon diagrams of
the O-Mad2–C-Mad2 dimer and the Mad2-p31^comet complex. The
C-Mad2 molecules in both structures are superimposed. The color
scheme is the same as in (C) and (D).
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The above figures are
reprinted
from an Open Access publication published by Cell Press:
Cell
(2007,
131,
744-755)
copyright 2007.
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Secondary reference #1
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Title
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The mad2 spindle checkpoint protein has two distinct natively folded states.
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Authors
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X.Luo,
Z.Tang,
G.Xia,
K.Wassmann,
T.Matsumoto,
J.Rizo,
H.Yu.
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Ref.
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Nat Struct Mol Biol, 2004,
11,
338-345.
[DOI no: ]
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PubMed id
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Figure 2.
Figure 2. Ribbon drawing of the structures of N1-Mad2 (left)16,
N2-Mad2 R133A (middle, this study), and ligand-bound Mad2
(right)11. The  -strands
are blue,  -helices
green, and loops ivory. The non-natural Mad2-binding peptide,
MBP1, is red. The structural elements of Mad2 that undergo major
changes between the N1 and N2 conformers or upon peptide binding
are yellow and orange. The strands are numbered 1 -8 and the
helices are labeled A -C in the N1-Mad2 structure. MBP1 is
labeled as 1'
in the Mad2 -MBP1 complex. The secondary structure elements of
the N2-Mad2 R133A and Mad2 -MBP1 structures are labeled
similarly to those of N1-Mad2 with the exception of 9,
which is unstructured in N1-Mad2. Arg133 is shown as
ball-and-stick in the N1-Mad2 structure. Generated with
MolScript40 and Raster3D^41.
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Figure 6.
Figure 6. Mad1 facilitates the N1-N2 conversion of Mad2 in vitro.
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The above figures are
reproduced from the cited reference
with permission from Macmillan Publishers Ltd
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Secondary reference #2
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Title
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The mad2 spindle checkpoint protein undergoes similar major conformational changes upon binding to either mad1 or cdc20.
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Authors
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X.Luo,
Z.Tang,
J.Rizo,
H.Yu.
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Ref.
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Mol Cell, 2002,
9,
59-71.
[DOI no: ]
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PubMed id
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Figure 4.
Figure 4. Binding of Cdc20P1, Mad1P1, and MBP1 to Mad2
Monitored by NMR(A) Overlay of the ^1H-^15N HSQC spectra of the
free ΔN10-Mad2 (in black) and the ΔN10-Mad2-Cdc20P1 complex
(in red).(B) Overlay of the ^1H-^15N HSQC spectra of the free
ΔN10-Mad2 (in black) and the ΔN10-Mad2-Mad1P1 complex (in
cyan).(C) Overlay of the ^1H-^15N HSQC spectra of the
ΔN10-Mad2-Cdc20P1 complex (in red) and the ΔN10-Mad2-Mad1P1
complex (in cyan).(D) Overlay of the ^1H-^15N HSQC spectra of
the free ΔN10-Mad2 (in black) and the ΔN10-Mad2-MBP1 complex
(in red).
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Figure 5.
Figure 5. Solution Structure of Mad2-MBP1 and Comparison
with that of the Free Mad2(A) Stereo-view of the overlaid
backbone traces of the 25 final NMR structures of human Mad2 in
complex with MBP1. The β strands are shown in blue; α helices
in green; and the loops in gray. MBP1 is colored in red.
Generated with the program MOLMOL (Koradi et al., 1996).(B)
Ribbon drawing of the free (left) and ligand-bound (right) Mad2
structures. The β strands are shown in blue; α helices in
green; and the loops in cyan. MBP1 is colored in red. The
structural elements of Mad2 that undergo major changes upon
peptide binding are colored yellow. The strands are numbered
1–8 while the helices are labeled A–C in the free Mad2
structure. MBP1 is labeled as β1′ in the Mad2-MBP1 complex.
The rest of the secondary structure elements are labeled in a
manner similar to the free Mad2 with the exception of β9, which
is unstructured in free Mad2.(C) Same as (B) but rotated 90°
along the vertical (y) axis. Generated with the programs
Molscript (Kraulis, 1991) and Raster3D.
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The above figures are
reproduced from the cited reference
with permission from Cell Press
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Secondary reference #3
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Title
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Structure of the mad2 spindle assembly checkpoint protein and its interaction with cdc20.
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Authors
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X.Luo,
G.Fang,
M.Coldiron,
Y.Lin,
H.Yu,
M.W.Kirschner,
G.Wagner.
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Ref.
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Nat Struct Biol, 2000,
7,
224-229.
[DOI no: ]
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PubMed id
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Figure 4.
Figure 4. The Cdc20 binding surface of Mad2. a, Molecular
surface of Mad2. The conserved surface residues are in yellow
and labeled; the rest are in white. b, Molecular surface of Mad2
in the same orientation as in (a) except that it is colored
according to electrostatic potential: blue for basic residues;
white for hydrophobic residues; and red for acidic residues. c,
Ribbon drawing of Mad2 shown in the same orientation as in (a)
and with the conserved surface residues shown in ball-and-stick
models and colored in yellow. d -f , Same as (a -c) except that
they are rotated 180° along the y-axis. Molecular surfaces were
displayed using GRASP38 and ribbons were generated with MOLMOL37.
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Figure 6.
Figure 6. Hypothetical models for the stabilization of the Mad2
-Cdc20 interaction by the spindle assembly checkpoint. An
inhibitory signal is generated at the unattached kinetochore
(signified by a red dot), which is then transduced by Bub1and
Bub3. Bub1 is a kinase that forms a complex with Bub3. Bub1 and
Bub3 lie upstream of Mad1 and Mad2, which also interact
physically. Mad1 is a coiled-coil protein that can form a
homodimer and becomes phosphorylated upon activation of the
checkpoint. However, the role of Mad1 phosphorylation is
unclear. Mad2 binds to the C-terminal third of the Mad1 protein
and this binding requires the C-terminal tail of Mad2. To
prevent the activation of the APCCdc20 complex, Mad2 has to
associate with Cdc20. In one model, the Mad2 -Cdc20 complex is
further strengthened by factor X; the binding of factor X to
Mad2 -Cdc20 is in turn regulated by the checkpoint. In the
second model, the binding of Mad2 to Cdc20 is inhibited by
factor Y, whose activity is suppressed by the checkpoint. The
two mechanisms are not mutually exclusive. Because the
C-terminal tail of Mad2 is required for its own oligomerization
and for its interactions with Mad1 and CDC20, we speculate that
the regulation of Mad2 may involve conformational changes of its
C-terminal region.
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The above figures are
reproduced from the cited reference
with permission from Macmillan Publishers Ltd
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