COPZ2

COPZ2 is a human gene that encodes the zeta-2 subunit of the coatomer protein complex I (COPI). The COPI complex is a seven-subunit coat that coats vesicles budding from the Golgi and mediates retrograde transport to the endoplasmic reticulum as well as intra-Golgi trafficking. COPZ2 is a paralog of COPZ1; both encode zeta subunits that can contribute to COPI coat formation, with potential functional redundancy.

The COPI coats assemble on Golgi membranes with ARF1 GTPase and recruit partner subunits to form vesicles. Zeta-COP participates in stabilizing the coat and in cargo selection, helping cargo receptors and lumenal proteins be retrieved to the ER. The precise roles of zeta-2 relative to zeta-1 are still under study, but COPZ2 is expressed in many tissues and localizes to the Golgi apparatus.

In humans, COPZ2 interacts with other COPI subunits, including alpha-, beta-, beta'-, gamma-, delta-, and epsilon-COP, as well as ARF1, and participates in vesicle trafficking cycles essential for Golgi function. The gene is conserved across vertebrates, reflecting the importance of COPI-mediated transport in fundamental cellular processes.

Clinical significance is not well defined; no common monogenic disorder is attributed to COPZ2 mutations, though alterations in vesicular trafficking pathways have been investigated in cancer and neurodevelopmental contexts. Research using cell and animal models continues to clarify the specific contributions of zeta-2-COP to COPI function and Golgi homeostasis.