Roles of the Picornaviral 3C Proteinase in the Viral Life Cycle and Host Cells

Sun, Di; Chen, Shun; Cheng, Anchun; Wang, Mingshu

Except for their crucial role in the replication of picornaviruses and inhibition of protein synthesis in host cells, the 3C pro s of PV and FMDV have been previously reported to mediate cleavage of microtubule-associated protein 4(MAP-4) and cause disruption of the microtubule-organizing centre (MTOC) [87, 88] . Subsequent studies have revealed that FMDV 3C pro leads to fragmentation of the Golgi apparatus, which blocks the transport of proteins from the Golgi to the plasma membrane. Some scholars have studied the connection between Golgi fragmentation, microtubule depolymerization and secretion blockade. Through a series of experiments, it has been confirmed that FMDV 3C pro blocks secretion in the following two ways: 3C pro processes 2BC into 2B and 2C, which bind to the Golgi compartment to block intra-Golgi transport, and instead of physical binding, 3C pro blocks secretion by degrading proteins necessary for intra-Golgi transports. Both of these routers depend on the proteolytic activity of 3C pro [89] . Further research is needed to understand whether there is a connection between cleavage and the reduction of immune responses or between cleavage and the transmission of virus.