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PDBsum entry 2w2v
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Signaling protein
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PDB id
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2w2v
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Contents |
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171 a.a.
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170 a.a.
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161 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 insights into formation of an active signaling complex between rac and phospholipase c gamma 2.
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Authors
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T.D.Bunney,
O.Opaleye,
S.M.Roe,
P.Vatter,
R.W.Baxendale,
C.Walliser,
K.L.Everett,
M.B.Josephs,
C.Christow,
F.Rodrigues-Lima,
P.Gierschik,
L.H.Pearl,
M.Katan.
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Ref.
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Mol Cell, 2009,
34,
223-233.
[DOI no: ]
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PubMed id
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Abstract
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Rho family GTPases are important cellular switches and control a number of
physiological functions. Understanding the molecular basis of interaction of
these GTPases with their effectors is crucial in understanding their functions
in the cell. Here we present the crystal structure of the complex of Rac2 bound
to the split pleckstrin homology (spPH) domain of phospholipase C-gamma(2)
(PLCgamma(2)). Based on this structure, we illustrate distinct requirements for
PLCgamma(2) activation by Rac and EGF and generate Rac effector mutants that
specifically block activation of PLCgamma(2), but not the related PLCbeta(2)
isoform. Furthermore, in addition to the complex, we report the crystal
structures of free spPH and Rac2 bound to GDP and GTPgammaS. These structures
illustrate a mechanism of conformational switches that accompany formation of
signaling active complexes and highlight the role of effector binding as a
common feature of Rac and Cdc42 interactions with a variety of effectors.
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Figure 1.
Figure 1. Crystal Structure of the
Rac2^G12V(GTPγS)/PLCγ[2]spPH Complex
Domain organization
of PLCγ[2] (A) shows domains common to all families (nPH,
EF-hands, catalytic, and C2) and domains specific to PLCγ
family (nSH2, cSH2, SH3, and spPH); spPH is shown in orange.
Overview of the Rac2^G12V(2-177) GTPγS/PLCγ[2]spPH complex
structure (B). Surface topology (shown as translucent surfaces)
and ribbon representation of the complex show the spPH domain in
orange and the Rac2 molecule in blue. The Rac2 switch I region
is shown in green, and the switch II region is shown in magenta.
The GTPγS molecule bound to Rac2 is in ball-and-stick
representation. Close-up of the interaction interface is viewed
from the side with important amino acid residues of both Rac2
and spPH represented as ball and sticks (C). Also shown is a
close-up from above with important Rac2 amino acid residues
(ball-and-stick representation) and the spPH surface (D). The
hydrophobic cleft into which Rac2 residues Val36 and Phe37
protrude can be clearly seen. The summary of interactions at the
interface is illustrated schematically highlighting the
predominant types of bonding between the two species in the
complex (E).
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Figure 6.
Figure 6. Effector-Facilitated Conformational Changes in
Rac/Cdc42 Proteins
Comparison of switch I regions of
uncomplexed, GTP analog-bound Ras (pdb: 121P) (A) with an
overlay of Rac2 and Cdc42 uncomplexed, GTP analog-bound
structures (pdb: 2w2v and 2QRZ) ([B], left) and Rac2 and Cdc42
GTP analog-bound structures (overlay) from complexes with
PLCγ[2] (pdb: 2w2x) and Par6 (pdb: 1NF3), respectively ([B],
right). Conformations of switch I region and orientation of
indicated key residues in free Rac/CDC42-(GTP) proteins and in
complexes with their effectors are clearly different. Binding of
several effectors to Rac/Cdc42 proteins involves interaction
with switch I residues Val36 and Phe37 that stabilizes
signaling-active (state 2) conformation where other switch I
residues, Thr35 and Tyr32, can coordinate γ-phosphate of GTP.
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The above figures are
reprinted
by permission from Cell Press:
Mol Cell
(2009,
34,
223-233)
copyright 2009.
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