7P3Z

Homology model of the full-length AP-3 complex in a stretched open conformation

7P3Z の概要

• エントリーDOI: 10.2210/pdb7p3z/pdb
• EMDBエントリー: 13189
• 分子名称: AP-3 complex subunit delta, Y55_G0035830.mRNA.1.CDS.1, AP-3 complex subunit mu, ... (4 entities in total)
• 機能のキーワード: adaptor protein, vesicle transport, ap-3, homology model, transport protein
• 由来する生物種: Saccharomyces cerevisiae (Baker's yeast); 詳細
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 279465.74

構造登録者

Schubert, E.,Raunser, S. (登録日: 2021-07-09, 公開日: 2021-09-29, 最終更新日: 2021-12-08)

主引用文献

Schoppe, J.,Schubert, E.,Apelbaum, A.,Yavavli, E.,Birkholz, O.,Stephanowitz, H.,Han, Y.,Perz, A.,Hofnagel, O.,Liu, F.,Piehler, J.,Raunser, S.,Ungermann, C.
Flexible open conformation of the AP-3 complex explains its role in cargo recruitment at the Golgi.
J.Biol.Chem., 297:101334-101334, 2021

PubMed Abstract: Vesicle formation at endomembranes requires the selective concentration of cargo by coat proteins. Conserved adapter protein complexes at the Golgi (AP-3), the endosome (AP-1), or the plasma membrane (AP-2) with their conserved core domain and flexible ear domains mediate this function. These complexes also rely on the small GTPase Arf1 and/or specific phosphoinositides for membrane binding. The structural details that influence these processes, however, are still poorly understood. Here we present cryo-EM structures of the full-length stable 300 kDa yeast AP-3 complex. The structures reveal that AP-3 adopts an open conformation in solution, comparable to the membrane-bound conformations of AP-1 or AP-2. This open conformation appears to be far more flexible than AP-1 or AP-2, resulting in compact, intermediate, and stretched subconformations. Mass spectrometrical analysis of the cross-linked AP-3 complex further indicates that the ear domains are flexibly attached to the surface of the complex. Using biochemical reconstitution assays, we also show that efficient AP-3 recruitment to the membrane depends primarily on cargo binding. Once bound to cargo, AP-3 clustered and immobilized cargo molecules, as revealed by single-molecule imaging on polymer-supported membranes. We conclude that its flexible open state may enable AP-3 to bind and collect cargo at the Golgi and could thus allow coordinated vesicle formation at the trans-Golgi upon Arf1 activation.

PubMed: 34688652
DOI: 10.1016/j.jbc.2021.101334

実験手法

ELECTRON MICROSCOPY (10.5 Å)