PMID: 23415225

Authors:

Ren X, Farias GG, Canagarajah BJ, Bonifacino JS, Hurley JH

Title:

Structural Basis for Recruitment and Activation of the AP-1 Clathrin Adaptor Complex by Arf1.

Journal:

Cell. 2013 Feb 14;152(4):755-67. doi: 10.1016/j.cell.2012.12.042.

Abstract:

AP-1 is a clathrin adaptor complex that sorts cargo between the trans-Golgi network and endosomes. AP-1 recruitment to these compartments requires Arf1-GTP. The crystal structure of the tetrameric core of AP-1 in complex with Arf1-GTP, together with biochemical analyses, shows that Arf1 activates cargo binding by unlocking AP-1. Unlocking is driven by two molecules of Arf1 that bridge two copies of AP-1 at two interaction sites. The GTP-dependent switch I and II regions of Arf1 bind to the N terminus of the beta1 subunit of one AP-1 complex, while the back side of Arf1 binds to the central part of the gamma subunit trunk of a second AP-1 complex. A third Arf1 interaction site near the N terminus of the gamma subunit is important for recruitment, but not activation. These observations lead to a model for the recruitment and activation of AP-1 by Arf1.