COPII

COPII is a coatomer, a type of vesicle coat protein that transports proteins from the rough endoplasmic reticulum to the Golgi apparatus. This process is termed anterograde transport, in contrast to the retrograde transport associated with the COPI protein. The name 'COPII' refers to the specific coat protein complex that initiates the budding process. The coat consists of large protein subcomplexes that are made of four different protein subunits.Conformation of the CopII protein complexed with the snare protein Bet1 (PDB: 1PCX​).Conformation of the CopII protein that is complexed with the snare protein Sed5 (PDB: 1PD0​). COPII is a coatomer, a type of vesicle coat protein that transports proteins from the rough endoplasmic reticulum to the Golgi apparatus. This process is termed anterograde transport, in contrast to the retrograde transport associated with the COPI protein. The name 'COPII' refers to the specific coat protein complex that initiates the budding process. The coat consists of large protein subcomplexes that are made of four different protein subunits. COPII's coat is composed of five proteins: Sar1, Sec23, Sec24, Sec13, and Sec31.These proteins dimerize to form larger protein complexes: