COPB2

COPB2, or coatomer protein complex subunit beta' (beta prime), is a protein encoded by the COPB2 gene in humans. It is a subunit of the coatomer protein complex I (COPI), a cytosolic multiprotein coat that drives vesicular trafficking within the early secretory pathway.

COPI mediates retrograde transport from the Golgi apparatus back to the endoplasmic reticulum and participates in intra-Golgi trafficking. The coatomer complex is recruited to Golgi membranes by the small GTPase ARF1; COPB2 contributes to coat assembly, stability, and cargo selection by providing interfaces for interaction with other coatomer subunits and with cargo receptors.

COPB2 is a conserved, ubiquitously expressed cytosolic protein that cycles on and off membranes during vesicle budding. It localizes primarily to the Golgi apparatus and cytosol, and its function is essential for proper trafficking and maintenance of Golgi structure in many organisms.

Disruption of COPI components can impair protein trafficking and secretion, highlighting the importance of COPB2 in cellular homeostasis. The gene has been studied mainly in cellular and molecular biology contexts to understand vesicle formation and membrane trafficking.