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PDBsum entry 2raj
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Structural protein
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PDB id
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2raj
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References listed in PDB file
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Key reference
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Title
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The px-Bar membrane-Remodeling unit of sorting nexin 9.
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Authors
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O.Pylypenko,
R.Lundmark,
E.Rasmuson,
S.R.Carlsson,
A.Rak.
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Ref.
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EMBO J, 2007,
26,
4788-4800.
[DOI no: ]
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PubMed id
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Abstract
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Sorting nexins (SNXs) form a family of proteins known to interact with
components in the endosomal system and to regulate various steps of vesicle
transport. Sorting nexin 9 (SNX9) is involved in the late stages of
clathrin-mediated endocytosis in non-neuronal cells, where together with the
GTPase dynamin, it participates in the formation and scission of the vesicle
neck. We report here crystal structures of the functional membrane-remodeling
unit of SNX9 and show that it efficiently tubulates lipid membranes in vivo and
in vitro. Elucidation of the protein superdomain structure, together with
mutational analysis and biochemical and cell biological experiments,
demonstrated how the SNX9 PX and BAR domains work in concert in targeting and
tubulation of phosphoinositide-containing membranes. The study provides insights
into the SNX9-induced membrane modulation mechanism.
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Figure 2.
Figure 2 (A) Side view of the SNX9 PX-BAR dimer structure ribbon
diagram. BAR domains are shown in red, PX in blue, and the novel
Yoke (Y) subdomain in yellow. N- and C-termini are labeled. (B)
Top view of the SNX9 PX-BAR dimer structure. The domains are
labeled. (C) Ribbon representation of SNX9 Yoke (Y) subdomain
structure. The Yoke domain consists of two parts: Y[N] derived
from amino-acid residues 214–250 and Y[C] from 375–390.
Secondary structure elements are labeled. (D) Sequence alignment
of human SNX9 (Q9Y5X1), SNX18 (AAH67860), and SNX30 (ABN09670)
PX-BAR domains. The proteins represent a subfamily of PX-BAR
SNXs. Secondary structure elements corresponding to the SNX9
structure are monitored. Coloring corresponds to that from
panels A–C. Helices are labeled with H,  -strands
with S, and P denotes a proline-rich motif. The amino-acid
residues involved in the dimerization are labeled (+,
hydrophobic bar–bar contacts; ^*, H-bond bar–bar contacts),
as well as residues involved in interdomain interaction (§,
hydrophobic bar-px:y contacts; &, H-bonds bar-px:y contacts).
Symbols of consensus sequence are: 2, E/Q; 3, T/S; 4, K/R; 5,
Y/F; and 6, hydrophobic.
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Figure 3.
Figure 3 (A) SNX9 BAR domain monomer in rainbow colors from the
N-terminus in blue to C-terminus in red.  -helices
are labeled. (B) SNX9 BAR domain. The core and arm regions are
monitored, and the proline amino-acid residues at the -helices
kinks are labeled.
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The above figures are
reprinted
by permission from Macmillan Publishers Ltd:
EMBO J
(2007,
26,
4788-4800)
copyright 2007.
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