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* Residue conservation analysis
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References listed in PDB file
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Key reference
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Title
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Crystal structure of the phosphatidylinositol 3,4-Bisphosphate-Binding pleckstrin homology (ph) domain of tandem ph-Domain-Containing protein 1 (tapp1): molecular basis of lipid specificity.
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Authors
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C.C.Thomas,
S.Dowler,
M.Deak,
D.R.Alessi,
D.M.Van aalten.
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Ref.
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Biochem J, 2001,
358,
287-294.
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PubMed id
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Abstract
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Phosphatidylinositol 3,4,5-trisphosphate [PtdIns(3,4,5)P(3)] and its immediate
breakdown product PtdIns(3,4)P(2) function as second messengers in growth
factor- and insulin-induced signalling pathways. One of the ways that these
3-phosphoinositides are known to regulate downstream signalling events is by
attracting proteins that possess specific PtdIns-binding pleckstrin homology
(PH) domains to the plasma membrane. Many of these proteins, such as protein
kinase B, phosphoinositide-dependent kinase 1 and the dual adaptor for
phosphotyrosine and 3-phosphoinositides (DAPP1) interact with both
PtdIns(3,4,5)P(3) and PtdIns(3,4)P(2) with similar affinity. Recently, a new
PH-domain-containing protein, termed tandem PH-domain-containing protein (TAPP)
1, was described which is the first protein reported to bind PtdIns(3,4)P(2)
specifically. Here we describe the crystal structure of the
PtdIns(3,4)P(2)-binding PH domain of TAPP1 at 1.4 A (1 A=0.1 nm) resolution in
complex with an ordered citrate molecule. The structure is similar to the known
structure of the PH domain of DAPP1 around the D-3 and D-4
inositol-phosphate-binding sites. However, a glycine residue adjacent to the D-5
inositol-phosphate-binding site in DAPP1 is substituted for a larger alanine
residue in TAPP1, which also induces a conformational change in the neighbouring
residues. We show that mutation of this glycine to alanine in DAPP1 converts
DAPP1 into a TAPP1-like PH domain that only interacts with PtdIns(3,4)P(2),
whereas the alanine to glycine mutation in TAPP1 permits the TAPP1 PH domain to
interact with PtdIns(3,4,5)P(3).
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Secondary reference #1
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Title
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Identification of pleckstrin-Homology-Domain-Containing proteins with novel phosphoinositide-Binding specificities.
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Authors
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S.Dowler,
R.A.Currie,
D.G.Campbell,
M.Deak,
G.Kular,
C.P.Downes,
D.R.Alessi.
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Ref.
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Biochem J, 2000,
351,
19-31.
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PubMed id
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Secondary reference #2
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Title
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Structural basis for discrimination of 3-Phosphoinositides by pleckstrin homology domains.
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Authors
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K.M.Ferguson,
J.M.Kavran,
V.G.Sankaran,
E.Fournier,
S.J.Isakoff,
E.Y.Skolnik,
M.A.Lemmon.
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Ref.
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Mol Cell, 2000,
6,
373-384.
[DOI no: ]
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PubMed id
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Figure 1.
Figure 1. DAPP1-PH and Grp1-PH Recognize Distinct Patterns
of Phosphate Groups(A) Binding of Ins(1,3,4)P[3] (magenta,
squares), and Ins(1,5,6)P[3] (which has the same phosphate
arrangement as Ins(3,4,5)P[3]) (cyan, triangles) to DAPP1-PH
(left) and Grp1-PH (right) is compared using a
^3H-Ins(1,3,4,5)P[4] competition assay ([17]). DAPP1-PH binds
10-fold more strongly to Ins(1,3,4)P[3] than to the
Ins(3,4,5)P[3] analog, while the converse is true for
Grp1-PH.(B) Structures of the inositol trisphosphates.
Ins(1,3,4)P[3] (magenta) and Ins(3,4,5)P[3] (cyan) are
compared. Note that Ins(3,4,5)P[3] is equivalent to
Ins(1,5,6)P[3] except in the positioning of the single axial
hydroxyl group (2-OH). Ins(3,4,5)P[3] is not commercially
available, so Ins(1,5,6)P[3] was used for the experiment shown
in (A). Since Ins(3,5,6)P[3] and Ins(1,3,4)P[3] bind identically
to DAPP1-PH (Table 1), we suggest that the axial 2-hydroxyl is
not likely to be important in defining binding specificity.
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Figure 6.
Figure 6. Prediction of PH Domain 3-Phosphoinositide
SpecificityPH domains shown to recognize PI 3-kinase products
([15]) are aligned with Grp1-PH and Btk-PH (A) or DAPP1-PH (B),
according to whether they are predicted (see text) to make
direct side chain contacts with the 5-phosphate of
Ins(1,3,4,5)P[4]. Elements of secondary structure are delineated
with gray arrows (β strands) or a black bar (the C-terminal α
helix). Residues are colored when their side chain is involved
in interactions with Ins(1,3,4,5)P[4] in the Btk-PH, Grp1-PH, or
DAPP1-PH complex structures. Yellow represents interaction with
the 1-phosphate; red, the 3-phosphate; green, the 4-phosphate;
and blue, the 5-phosphate. Color coding is predicted for PH
domains of unknown structure. The 3-phosphoinositide binding
motif ([15]) in the β1/β2 region is also color coded as
described above. In (A), PH domains with names underlined are
known to select PtdIns(3,4,5)P[3] over PtdIns(3,4)P[2]. Others
are predicted to do so. In (B), DAPP1-PH and PKB-PH are both
known to bind almost equally to PtdIns(3,4,5)P[3] and
PtdIns(3,4)P[2]. Others are predicted to do so.
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The above figures are
reproduced from the cited reference
with permission from Cell Press
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