Coxsackievirus B3 entry into the host cell interferes with G-protein-mediated transmembrane signalling

In the present work we used various cell lines in order to study the possible effect of coxsackievirus B3 (CVB3) entry on the adenylyl cyclase transmembrane signalling system. A significant decrease (by about 10–20%) was found in forskolin-augmented as well as in AlF ₄ ^– - and GTPS-sensitive adenylyl cyclase activity in plasma membranes isolated from HeLa, HEp-2, Vero and green monkey kidney cells shortly (up to 60 min) preincubated with CVB3 (5 PFU/cell). Moreover, the ability of G-proteins derived from plasma membranes of infected cells to reconstitute AC activity in the cyc^– mutant of S49 cells was also reduced. Content of G-protein subunits, however, remained unchanged after CVB3 attachment. Functional alterations in the G-protein-mediated adenylyl cyclase signalling system were accompanied by a marked decrease (by about 20–40%) of intracellular cAMP levels in virus-affected cells. These findings demonstrate clearly that CVB3 may affect functioning of the G-protein regulated adenylyl cyclase transmembrane signalling system in virus-sensitive cells as early as during the first period of its contact with the cellular plasma membrane.