 |
PDBsum entry 1j2h
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Protein transport
|
PDB id
|
|
|
|
1j2h
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
References listed in PDB file
|
|
|
Key reference
|
|
|
Title
|
|
Molecular mechanism of membrane recruitment of gga by arf in lysosomal protein transport.
|
|
|
Authors
|
|
T.Shiba,
M.Kawasaki,
H.Takatsu,
T.Nogi,
N.Matsugaki,
N.Igarashi,
M.Suzuki,
R.Kato,
K.Nakayama,
S.Wakatsuki.
|
|
|
Ref.
|
|
Nat Struct Biol, 2003,
10,
386-393.
[DOI no: ]
|
|
|
PubMed id
|
|
|
|
|
|
Abstract
|
|
|
GGAs are critical for trafficking soluble proteins from the trans-Golgi network
(TGN) to endosomes/lysosomes through interactions with TGN-sorting receptors,
ADP-ribosylation factor (ARF) and clathrin. ARF-GTP bound to TGN membranes
recruits its effector GGA by binding to the GAT domain, thus facilitating
recognition of GGA for cargo-loaded receptors. Here we report the X-ray crystal
structures of the human GGA1-GAT domain and the complex between ARF1-GTP and the
N-terminal region of the GAT domain. When unbound, the GAT domain forms an
elongated bundle of three a-helices with a hydrophobic core. Structurally, this
domain, combined with the preceding VHS domain, resembles CALM, an AP180 homolog
involved in endocytosis. In the complex with ARF1-GTP, a helix-loop-helix of the
N-terminal part of GGA1-GAT interacts with the switches 1 and 2 of ARF1
predominantly in a hydrophobic manner. These data reveal a molecular mechanism
underlying membrane recruitment of adaptor proteins by ARF-GTP.
|
|
|
|
|
|
|
|
Figure 1.
Figure 1. Structures of the GGA1-GAT domain and its complex with
ARF1. a, Stereo diagram of the GGA1-GAT domain. The GAT
domain forms three  -helices
connected by loops of varying length. The final model is
complete except for the N-terminal 26 residues (166 -191, dotted
line) and the C-terminal 2 residues (304 -305), whose electron
density is weak. b, Stereo view of the omit F[o] -F[c] electron
density map of the GGA1 N-GAT (Leu178 -Asn194) within the ARF1
-N-GAT complex. The map was calculated to 1.6 Å resolution and
is displayed at 1.5  cutoff,
superimposed with a ball-and-stick model of the N-GAT domain. c,
Stereo view of the ARF1 -N-GAT complex. N-GAT forms a
helix-loop-helix motif facing switches 1 and 2 of ARF1-GTP. The
diagrams in (a) and (c) are shown in the same orientation, which
was chosen by the least-square minimization of the overlap of a
common helical region (199 -205, shown in red in a and c)
between the GAT domain and the ARF1 -N-GAT complex.
|
|
Figure 6.
Figure 6. Domain organization of GGA and a proposed model of the
interactions with its partners at several stages of the vesicle
formation: M6PR, ARF -GTP, clathrin N-terminal propeller and an
accessory protein. The N-terminal VHS domain recognizes the
sorting signals, such as M6PR (PDB entry 1JWG). The GAT domain
interacts with a membrane-bound ARF (this study). The subsequent
hinge region interacts with clathrin (clathrin terminal domain
in complex with the clathrin-box peptide from  3-hinge
of AP-3; PDB entry 1C9I). The sequence S*LLDDELM interact with
VHS domain (autoinhibition), where S* is phosphorylated^24.
Finally, the C-terminal GGA1 GAE domain is modeled from the
structure of the ear domain of  -adaptin
(PDB entry 1IU1) based on their similarity both in sequence and
function.
|
|
|
|
|
|
The above figures are
reprinted
by permission from Macmillan Publishers Ltd:
Nat Struct Biol
(2003,
10,
386-393)
copyright 2003.
|
|
|
|
|
|
|
