PDBsum entry 4q66

Protein transport

PDB id: 4q66

Contents

Protein chains

226 a.a.

158 a.a.

211 a.a.

171 a.a.

593 a.a.

557 a.a.

507 a.a.

338 a.a.

146 a.a.

139 a.a.

134 a.a.

86 a.a.

Ligands

GNP ×4

Metals

_MG ×4

References listed in PDB file

Key reference

• Title: Structural basis for membrane binding and remodeling by the exomer secretory vesicle cargo adaptor.
• Authors: J.E.Paczkowski, J.C.Fromme.
• Ref.: Dev Cell, 2014, 30, 610-624. [DOI no: 10.1016/j.devcel.2014.07.014]
• PubMed id: 25203211

Abstract

Cargo adaptor subunits of vesicle coat protein complexes sort transmembrane proteins to distinct membrane compartments in eukaryotic cells. The exomer complex is the only cargo adaptor known to sort proteins at the trans-Golgi network into secretory vesicles. Exomer function is regulated by the Arf1 GTPase, a master regulator of trafficking at the Golgi. We report the structure of exomer bound to two copies of Arf1. Exomer interacts with each Arf1 molecule via two surfaces, one of which is a noncanonical interface that regulates GTP hydrolysis. The structure uncovers an unexpected membrane-proximal hydrophobic element that exomer uses in cooperation with Arf1 to remodel membranes. Given the constrained motion of the exomer hinge region, we envision that exomer dynamically positions multiple membrane insertion elements to drive membrane fission. In contrast to other known cargo adaptors, exomer therefore couples two functions, cargo sorting and membrane fission, into a single complex.