The exomer cargo adaptor features a flexible hinge domain.
Richardson, B.C., Fromme, J.C.(2013) Structure 21: 486-492
- PubMed: 23395181
- DOI: https://doi.org/10.1016/j.str.2013.01.003
- Primary Citation of Related Structures:
4IN3 - PubMed Abstract:
Exomer is a cargo adaptor that mediates the sorting of specific plasma membrane proteins into vesicles at the trans-Golgi network. Cargo adaptors must bind to multiple partners, including their cargo, regulatory proteins, and the membrane surface. During biogenesis of a vesicle, the membrane makes a transition from a relatively flat surface to one of high curvature, requiring cargo adaptors to somehow maintain protein-protein and protein-membrane interactions on a changing membrane environment. Here, we present the crystal structure of a tetrameric Chs5/Bch1 exomer complex and use small-angle X-ray scattering to demonstrate its flexibility in solution. The structural data suggest that the complex flexes primarily around the dimeric N-terminal domain of the Chs5 subunits, which adopts a noncanonical β sandwich fold. We propose that this flexible hinge domain enables exomer to maintain interactions in the context of a dynamic membrane environment.
Organizational Affiliation:
Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA.