Ancestral coatomer element 1 (ACE1) of COPII coat complex assembly protein Sec16
COPII coat complex plays an important role in vesicular traffic of newly synthezised proteins from the endoplasmatic reticulum (ER) to the Golgi apparatus by mediating the formation of transport vesicles. COPII consists of an outer coat, made up of the scaffold proteins Sec31 and Sec13, and the cargo adaptor complex, Sec23 and Sec24, which are recruited by the small GTPase Sar1. Sec16 is involved in the early steps of the assembly process. Sec16 forms elongated heterotetramers with Sec13, Sec13-(Sec16)2-Sec13. It interacts with Sec13 by insertion of a single beta-blade to close the six-bladded beta propeller of Sec13. In the same way Sec13 interacts with Sec31 and Nup145C, a nuclear pore protein, all of these contain a structurally related ancestral coatomer element 1 (ACE1). Sec16 is believed to be a key component in maintaining the integrity of the ER exit site.
Jiyao W et al.(2023). "The conserved domain database in 2023.",