Role of Coatomer Protein I in Virus Replication

Coatomer protein I (COPI) is well known as the protein coat surrounding vesicles involved in returning endoplasmic reticulum (ER)-resident proteins to the ER. COPI coats are also found in vesicles involved in other trafficking processes including endocytosis, autophagy and anterograde transport in the secretory pathway. In view of the diverse functions of COPI proteins, it is expected that they will affect virus replication, and many reports of such COPI involvement have now appeared. The experimental approaches most often employ specific siRNA to deplete COPI subunits or brefeldin A to block COPI activation. Here we briefly describe the results obtained with viruses in which COPI is found to have a role in replication. The results demonstrate that COPI affects viruses quite differently with effects observed in processes such as entry, RNA replication, and intracellular transport of viral proteins.