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PDBsum entry 1jo8
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Structural protein
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PDB id
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1jo8
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Contents |
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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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Unusual binding properties of the sh3 domain of the yeast actin-Binding protein abp1: structural and functional analysis.
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Authors
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B.Fazi,
M.J.Cope,
A.Douangamath,
S.Ferracuti,
K.Schirwitz,
A.Zucconi,
D.G.Drubin,
M.Wilmanns,
G.Cesareni,
L.Castagnoli.
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Ref.
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J Biol Chem, 2002,
277,
5290-5298.
[DOI no: ]
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PubMed id
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Abstract
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Abp1p is an actin-binding protein that plays a central role in the organization
of Saccharomyces cerevisiae actin cytoskeleton. By a combination of two-hybrid
and phage-display approaches, we have identified six new ligands of the Abp1-SH3
domain. None of these SH3-mediated novel interactions was detected in recent all
genome high throughput protein interaction projects. Here we show that the
SH3-mediated association of Abp1p with the Ser/Thr kinases Prk1p and Ark1p is
essential for their localization to actin cortical patches. The Abp1-SH3 domain
has a rather unusual binding specificity, because its target peptides contain
the tetrapentapeptide +XXXPXXPX+PXXL with positive charges flanking the
polyproline core on both sides. Here we present the structure of the Abp1-SH3
domain solved at 1.3-A resolution. The peptide-binding pockets in the SH3 domain
are flanked by two acidic residues that are uncommon at those positions in the
SH3 domain family. We have shown by site-directed mutagenesis that one of these
negatively charged side chains may be the key determinant for the preference for
non-classical ligands.
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Figure 3.
Fig. 3. Localization of Prk1p to actin cortical patches
depends on an intact polyproline motif at its C terminus. Yeast
cells were transfected with plasmids directing the synthesis of
GFP-Prk1p (upper panel, PRK1) or GFP-Prk1p carrying a mutation
in the polyproline stretch (lower panel, PRK1 mut poly P). In
the panels on the left, the clear spots are attributed to
fluorescence of the GFP-Prk1p hybrid protein. Actin was
visualized in the two panels on the right by staining with
rhodamine-conjugated phalloidin (Rh). To avoid disturbing cell
physiology by overexpressing the Prk1p kinase, a mutationally
inactivated kinase was used in this experiment (GFP-Prk1p K56A).
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Figure 5.
Fig. 5. Superposition of the Abp1p-SH3 domain (red) with
Sem5-SH3 (green) and c-Abl-SH3 (blue). The residues in the
Abp1-SH3-PXXP-binding site are labeled. They overlap almost
perfectly to those in Sem5-SH3 and c-Abl-SH3. The figure was
produced using MOLSCRIPT (49). Y53, Tyr-53; Y9, Tyr-9; W35,
Trp-35; N52, Asn-52; Y7, Tyr-7; P50, Pro-50.
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The above figures are
reprinted
by permission from the ASBMB:
J Biol Chem
(2002,
277,
5290-5298)
copyright 2002.
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