Poliovirus infection blocks ERGIC-to-Golgi trafficking and induces microtubule-dependent disruption of the Golgi complex

Cells infected with poliovirus exhibit a rapid inhibition of protein secretion and disruption of the Golgi complex. Neither the precise step at which the virus inhibits protein secretion nor the fate of the Golgi complex during infection has been determined. We find that transport-vesicle exit from the endoplasmic reticulum (ER) and trafficking to the ER-Golgi intermediate compartment (ERGIC) are unaffected in the poliovirus-infected cell. By contrast, poliovirus infection blocks transport from the ERGIC to the Golgi complex. Poliovirus infection also induces fragmentation of the Golgi complex resulting in diffuse distribution of both large and small vesicles throughout the cell. Pre-treatment with nocodazole prevents complete fragmentation, indicating that microtubules are required for poliovirus-induced Golgi dispersion. However, virally induced inhibition of the secretory pathway is not affected by nocodazole, and Golgi dispersion was found to occur during infection with mutant viruses with reduce ability to inhibit protein secretion. We conclude that the dispersion of the Golgi complex is not in itself the cause of inhibition of traffic between the ERGIC and the Golgi. Instead, these phenomena are independent effects of poliovirus infection on the host secretory complex.