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PDBsum entry 1bb9
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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 amphiphysin-2 sh3 domain and its role in the prevention of dynamin ring formation.
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Authors
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D.J.Owen,
P.Wigge,
Y.Vallis,
J.D.Moore,
P.R.Evans,
H.T.Mcmahon.
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Ref.
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Embo J, 1998,
17,
5273-5285.
[DOI no: ]
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PubMed id
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Abstract
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The amphiphysins are brain-enriched proteins, implicated in clathrin-mediated
endocytosis, that interact with dynamin through their SH3 domains. To elucidate
the nature of this interaction, we have solved the crystal structure of the
amphiphysin-2 (Amph2) SH3 domain to 2.2 A. The structure possesses several
notable features, including an extensive patch of negative electrostatic
potential covering a large portion of its dynamin binding site. This patch
accounts for the specific requirement of amphiphysin for two arginines in the
proline-rich binding motif to which it binds on dynamin. We demonstrate that the
interaction of dynamin with amphiphysin SH3 domains, unlike that with SH3
domains of Grb2 or spectrin, prevents dynamin self-assembly into rings. Deletion
of a unique insert in the n-Src loop of Amph2 SH3, a loop adjacent to the
dynamin binding site, significantly reduces this effect. Conversely, replacing
the n-Src loop of the N-terminal SH3 domain of Grb2 with that of Amph2 causes it
to favour dynamin ring disassembly. Transferrin uptake assays show that
shortening the n-Src loop of Amph2 SH3 reduces the ability of this domain to
inhibit endocytosis in vivo. Our data suggest that amphiphysin SH3 domains are
important regulators of the multimerization cycle of dynamin in endocytosis.
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Figure 4.
Figure 4 Surface representations of SH3 domains from Abl, Sem5
and Amph2. The pictures on the left depict surface accessible
hydrophobic regions coloured green to yellow for increasing
hydrophobicity (M.Noble, X objects, unpublished). Amph2 SH3
shows only two hydrophobic patches as opposed to the three
present in Abl and Sem5. On the right are representations of
electrostatic potential (created using GRASP) showing the large
negatively charged patch (red) on the peptide binding surface
(the peptide is shown in the case of Abl and Sem5). The
representations show the peptide binding surfaces of the SH3
domains with the n-Src loops pointing toward the top of the
page. Coordinates for the SH3 domain of Abl (Musacchio et al.,
1994) and the N-terminal SH3 domain of sem5 (Lim et al., 1994)
were obtained from the Protein Data Bank.
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Figure 5.
Figure 5 Point mutations in the Amph2 SH3 domain. (A) Structure
of Amph2 SH3 showing positions of key mutated residues, coloured
according to type. Hydrophobic residues are coloured green and
acidic residues in magenta. The longer n-Src loop which is
unique to the amphiphysins (the DAPS) that is exchanged for the
shorter homologous loop from Grb2 NSH3 is coloured blue. (B)
Effect of point mutations in GST Amph2 SH3 domain on its ability
to bind dynamin. (C) Interaction between Amph2 SH3 and dynamin
is sensitive to pH. Binding to wild-type is maximal at pH 7.0,
but rapidly declines as pH is either increased or decreased.
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The above figures are
reprinted
from an Open Access publication published by Macmillan Publishers Ltd:
Embo J
(1998,
17,
5273-5285)
copyright 1998.
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