A microscopy study tracks vesicles leaving the endoplasmic reticulum and fusing with the Golgi. Which protein coat assembled these budding carriers?

Core Concept

COPII coat complexes assemble at ER exit sites, curve the membrane into buds, and select cargo for forward movement toward the Golgi. A small GTPase drives assembly, and after budding the coat sheds so vesicles can fuse with their target. Anterograde ER-to-Golgi transport is the defining job of COPII.