 |
PDBsum entry 2k8p
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Signaling protein
|
PDB id
|
|
|
|
2k8p
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
References listed in PDB file
|
|
|
Key reference
|
|
|
Title
|
|
Characterization of the structural features and interactions of sclerostin: molecular insight into a key regulator of wnt-Mediated bone formation.
|
|
|
Authors
|
|
V.Veverka,
A.J.Henry,
P.M.Slocombe,
A.Ventom,
B.Mulloy,
F.W.Muskett,
M.Muzylak,
K.Greenslade,
A.Moore,
L.Zhang,
J.Gong,
X.Qian,
C.Paszty,
R.J.Taylor,
M.K.Robinson,
M.D.Carr.
|
|
|
Ref.
|
|
J Biol Chem, 2009,
284,
10890-10900.
[DOI no: ]
|
|
|
PubMed id
|
|
|
|
|
|
Abstract
|
|
|
The secreted glycoprotein sclerostin has recently emerged as a key negative
regulator of Wnt signaling in bone and has stimulated considerable interest as a
potential target for therapeutics designed to treat conditions associated with
low bone mass, such as osteoporosis. We have determined the structure of
sclerostin, which resulted in the identification of a previously unknown binding
site for heparin, suggestive of a functional role in localizing sclerostin to
the surface of target cells. We have also mapped the interaction site for an
antibody that blocks the inhibition of Wnt signaling by sclerostin. This shows
minimal overlap with the heparin binding site and highlights a key role for this
region of sclerostin in protein interactions associated with the inhibition of
Wnt signaling. The conserved N- and C-terminal arms of sclerostin were found to
be unstructured, highly flexible, and unaffected by heparin binding, which
suggests a role in stabilizing interactions with target proteins.
|
|
|
|
|
|
|
|
Figure 4.
Surface features of sclerostin. Panels A and B show contact
surface views of sclerostin, which are colored according to
electrostatic potential, with areas of significant positive
charge shown in blue, significant negative charge in red, and
neutral in white. The orientation of the protein in panel A is
equivalent to the ribbon representation in panel C. The location
of the hydrophobic patch on the concave surface of the extended
finger-like structures is indicated by the arrow. Panels C and D
show a ribbon representation of sclerostin, with the positions
of the basic side chains from arginine and lysine residues
highlighted.
|
|
Figure 6.
Localization of sclerostin to the surface of cells. The top
section of panel A shows a Western blot (with an antibody to
sclerostin) of 24-h supernatants obtained from MC3T3-E1 cells
transfected with wild type human sclerostin. The transfections
and treatments were as follows: 1, empty vector; 2, sclerostin;
3, empty vector with heparin added to a final concentration of
500 μg/ml; 4-12, sclerostin with heparin added to final
concentrations of 500, 250, 100, 50, 25, 12.5, 1, 0.5, and 0.25
μg/ml, respectively. The bottom section of panel A shows the
Western blot of samples generated from corresponding wells
incubated with a lysis buffer to determine the total amount of
sclerostin being produced. The top section of panel B shows the
Western blot (with an antibody to sclerostin) obtained for
samples of 24-h supernatants from MC3T3-E1 cells transfected
with vectors encoding wild type or mutant sclerostin. The
transfections were as follows: 1, empty vector; 2, wild type
sclerostin; 3, sclerostin R114A, R116A, and R119A; 4, sclerostin
K134A and R136A; 5, sclerostin R97A, K99A, and R102A; 6,
sclerostin K142A, K144A, and R145A. The bottom section of panel
B shows the Western blot obtained for equivalent samples of
total cell lysates.
|
|
|
|
|
|
The above figures are
reprinted
from an Open Access publication published by the ASBMB:
J Biol Chem
(2009,
284,
10890-10900)
copyright 2009.
|
|
|
|
|
|
|
