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References listed in PDB file
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Key reference
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Title
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A unique set of sh3-Sh3 interactions controls ib1 homodimerization.
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Authors
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O.Kristensen,
S.Guenat,
I.Dar,
N.Allaman-Pillet,
A.Abderrahmani,
M.Ferdaoussi,
R.Roduit,
F.Maurer,
J.S.Beckmann,
J.S.Kastrup,
M.Gajhede,
C.Bonny.
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Ref.
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EMBO J, 2006,
25,
785-797.
[DOI no: ]
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PubMed id
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Abstract
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Islet-brain 1 (IB1 or JIP-1) is a scaffold protein that interacts with
components of the c-Jun N-terminal kinase (JNK) signal-transduction pathway. IB1
is expressed at high levels in neurons and in pancreatic beta-cells, where it
controls expression of several insulin-secretory components and secretion. IB1
has been shown to homodimerize, but neither the molecular mechanisms nor the
function of dimerization have yet been characterized. Here, we show that IB1
homodimerizes through a novel and unique set of Src homology 3 (SH3)-SH3
interactions. X-ray crystallography studies show that the dimer interface covers
a region usually engaged in PxxP-mediated ligand recognition, even though the
IB1 SH3 domain lacks this motif. The highly stable IB1 homodimer can be
significantly destabilized in vitro by three individual point mutations directed
against key residues involved in dimerization. Each mutation reduces
IB1-dependent basal JNK activity in 293T cells. Impaired dimerization also
results in a reduction in glucose transporter type 2 expression and in
glucose-dependent insulin secretion in pancreatic beta-cells. Taken together,
these results indicate that IB1 homodimerization through its SH3 domain has
pleiotropic effects including regulation of the insulin secretion process.
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Figure 1.
Figure 1 Protein interaction domains of IB1. (A) IB1 is
characterized by a JBD (gray box, residues 154–182), SH3
(yellow box, residues 494–553) and a PID (orange box, residues
570–704). Residues are numbered according to the full-length
rat IB1 sequence (GenBank, AF108959). The seven PxxP motifs are
shown in black and red. Motifs marked in red are conserved in
rat, human and mouse IB1 and IB2. MKK7 and MLK3, two of the
known partners of IB1, bind to regions 287–472 and 473–709
of IB1, respectively. (B) Schematic representations of
full-length and C-terminal deletion mutants of IB1. Numbering
corresponds to the last amino-acid expressed in the various
constructs. Binding results described in Figure 2 are summarized
for all constructs. ND: not determined. (C) Sequence alignment
of rat, mouse and human IB1/JIP1 and IB2/JIP2 SH3 domains. The
sequence of rat IB1 (GenBank, AF108959), human JIP1 (Ensembl,
ENSP00000241014), mouse JIP1 (Ensembl, ENSMUSP00000050773), rat
IB2 (Ensembl, ENSRNOP00000050155), human IB2 (GenBank, AF218778)
and mouse JIP2 (Ensembl, ENSMUSP00000023291) are included. The
IB1 SH3 region is identical in all three species. Residues that
participate to IB1 dimerization as well as those expected to do
so in IB2 are shown in bold blue. Residues at the dimer
interface involved in inter-protomer salt bridges or hydrogen
bonds are shaded in green. Nonconserved amino acids between IB1
and IB2 are indicated with a star in the consensus sequence. The
positions of the  strands
1–5 and the 3[10]-helix are indicated in yellow.
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Figure 4.
Figure 4 Stereographic representation of the IB1 SH3 domain. (A)
The solvent-accessible surface of the IB1 SH3 domain. Contact
residues from the other molecule of the homodimer colored after
atom type are shown as sticks. Carbon atoms from residues 500 to
510 are colored in gray, those from residues 525 to 529 are in
yellow and the 542 to 547 region is shown in magenta. Residues
506 and 507 from both monomers are colored in cyan. (B) The
solvent-accessible surfaces of the IB1 and SEM-5 SH3 domains.
The surface of the IB1 SH3 domain is colored after atom type.
The superimposed solvent-accessible surface of SEM-5 (Lim et al,
1994) is shown as a yellow mesh, along with the bound
mSos-derived peptide PPPVPPR in sticks representation. The
canonical PPII binding sites are labeled (Yu et al, 1994).
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The above figures are
reprinted
by permission from Macmillan Publishers Ltd:
EMBO J
(2006,
25,
785-797)
copyright 2006.
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Secondary reference #1
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Title
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A cytoplasmic inhibitor of the jnk signal transduction pathway.
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Authors
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M.Dickens,
J.S.Rogers,
J.Cavanagh,
A.Raitano,
Z.Xia,
J.R.Halpern,
M.E.Greenberg,
C.L.Sawyers,
R.J.Davis.
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Ref.
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Science, 1997,
277,
693-696.
[DOI no: ]
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PubMed id
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Figure 2.
Fig. 2. Small NH[2]-terminal region of JIP-1 is sufficient
for interaction with JNK. (A) Cell lysates containing
Flag-epitope-tagged^ JNK1 were incubated with GST and GST-JIP-1
(residues 127 to 281) bound to glutathione-Sepharose, and bound
proteins were detected^ by protein immunoblot analysis with an
antibody to Flag. The effect of increasing concentrations (0, 4,
8, 16, 32, and 64 µg/ml) of^ synthetic peptide
corresponding to JIP-1 residues 148 to 174 or to a peptide with
a scrambled sequence (control) was examined. (B) Binding of JNK1
to GST and GST-JIP-1 (residues 127^ to 281) was examined in the
absence and presence of synthetic^ peptides (64 µg/ml).
The effect of the wild-type peptide (JIP-1^ residues 148 to
174), peptides with point mutations (substitution with Gly)
[Thr159  Gly159
(T159G)] (18), and a peptide with a scrambled primary sequence^
(control) was examined. The mutant JIP(159-162G) was
constructed^ by replacement of JIP-1 residues 159 to 162 with
Gly.
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Figure 4.
Fig. 4. JIP-1 inhibits pre-B cell transformation by Bcr-Abl.
(A) JNK activation by v-Abl and Bcr-Abl is suppressed by JIP-1.
JNK activity was measured in an immune-complex kinase assay of^
293 cell lysates by means of a polyclonal JNK antibody and the^
substrate GST-Jun. The effect of transfection of the cells with
plasmid vectors that express v-Abl, Bcr-Abl, and the JBD of
JIP-1^ (residues 127 to 281) is presented. (B) Primary mouse
marrow cells were infected with the bi-cistronic retroviruses
illustrated^ (20). The mean density (×10^4) (±SE)
of nonadherent pre-B cells on day 10 is presented. The^ data
shown are derived from three independent experiments plated^ in
triplicate. The empty box in the first line indicates that the
vector does not contain an insert in this position. (C)
Photomicrographs of representative plates from (B) are shown.
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The above figures are
reproduced from the cited reference
with permission from the AAAs
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Secondary reference #2
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Title
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Ib1, A jip-1-Related nuclear protein present in insulin-Secreting cells.
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Authors
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C.Bonny,
P.Nicod,
G.Waeber.
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Ref.
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J Biol Chem, 1998,
273,
1843-1846.
[DOI no: ]
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PubMed id
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Figure 1.
Fig. 1. IB1 differs from JIP-1 by the insertion of 47
amino acids, which contain a HLH and PID domain. A, schematic
diagram of IB1 and JIP1 with the putative motifs (HLH = helix
loop helix; PID = phosphotyrosine interaction domain; NTS =
nuclear translocation signal). B, amino acid sequence comparison
of IB1 with other bHLH proteins (31-34). Shaded amino acids are
conserved in at least five of the sequences represented. C,
sequence alignments of the^ PID domain of IB1 with several
members of PID-containing proteins (35-39). Shaded amino acids
are conserved in at least five of the^ sequences represented
(27).
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Figure 2.
Fig. 2. IB1 is abundantly expressed in insulin-secreting
cells. A, five micrograms of poly(A)+ RNA prepared from two
different insulin-secreting cell lines, from rat liver, kidney,
and whole pancreas, were analyzed by Northern blotting for IB1
gene expression. B, a total of 5 µg of RNA obtained^ from
isolated rat pancreatic islets incubated in 2.8 or 30 mM glucose
for 14 h were analyzed by Northern blotting, together with rat
liver and adipose tissue RNAs. C, Western blot analysis of  TC3 whole
cell extracts with the  -IB1
antibody demonstrated^ the presence of a 120-kDa product that
was not detected with the^ preimmune serum (CTRL). D, the IB1
protein is detected in 30 µg of whole cell extracts
obtained from isolated rat pancreatic islets when analyzed by
Western blotting with the -IB1
antibody. E, a plasmid containing the IB1 cDNA driven by a CMV
promoter or its parent vector was transiently transfected into
COS-7 cells and cytoplasmic (CE) or nuclear (NE) extracts
prepared 48 h after transfection. By Western blot analysis, IB1
is detected in the^ cytoplasm and the nucleus of the transfected
cells.
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The above figures are
reproduced from the cited reference
with permission from the ASBMB
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Author's comment:
IB1 differs from JIP-1 by the insertion of 47 amino acids, which contain a HLH and PID domain. A mutation in amino-terminal part of IB1 was described to be associated with a late-onset monogenic form of type 2 diabetes (Nature Gentics,2000)
Gérard Waeber
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Secondary reference #3
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Title
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Recruitment of jnk to jip1 and jnk-Dependent jip1 phosphorylation regulates jnk module dynamics and activation.
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Authors
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D.Nihalani,
H.N.Wong,
L.B.Holzman.
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Ref.
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J Biol Chem, 2003,
278,
28694-28702.
[DOI no: ]
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PubMed id
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Figure 2.
FIG. 2. Point mutations in the JNK binding domain of JIP1
abolish JIP-JNK interaction. COS 7 cells were co-transfected
with plasmids encoding Myc-JIP1 (0.5 µg) or
JIP1(R160G/P161G) (0.5 µg) and FLAG-JNK (0.5 µg) as
indicated. Cell lysates were analyzed by immunoprecipitation
using JIP1 antibody. Immune complexes were analyzed for the
presence of JNK using anti-FLAG antibody. Cell lysates from
corresponding experiments were analyzed for equivalent
expression of JIP1 and JNK.
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Figure 10.
FIG. 10. Interaction of JIP1 with components of the JNK
pathway. Schematic illustration of the dynamic relationship
between JIP1, DLK, and JNK. Under basal conditions DLK is bound
to JIP1 in a monomeric, inactive state. Upon stimulation, JNK is
recruited to JIP1. This recruitment leads to JIP1
phosphorylation, DLK dissociation from JIP1, and subsequent
dimerization and activation of DLK and ultimately JNK.
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The above figures are
reproduced from the cited reference
with permission from the ASBMB
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Secondary reference #4
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Title
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The jip group of mitogen-Activated protein kinase scaffold proteins.
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Authors
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J.Yasuda,
A.J.Whitmarsh,
J.Cavanagh,
M.Sharma,
R.J.Davis.
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Ref.
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Mol Cell Biol, 1999,
19,
7245-7254.
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PubMed id
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