Fig. 4.

Sec16 spatially restricts assembly of the COPII coat. a Outer coat components Sec13/31 form cuboctahedrons in their minimal state. The proline-rich region of Sec13 contacts Sec23/24 and Sar1 GTP stabilizing contacts between the inner and outer coat complexes. This also has the capacity to position Sec23/24 underneath the edges of the cage making the membrane surface (and associated proteins) more accessible. These are schematic illustrations generated using Autodesk Maya 8.0 and are not intended as accurate rendering of the precise atomic coordinates from crystallographic data