COXSACKIEVIRUS B3 ENTRY INTO THE HOST-CELL INTERFERES WITH G-PROTEIN-MEDIATED TRANSMEMBRANE SIGNALING

In the present work we used various cell lines in order to study the p ossible effect of coxsackievirus B3 (CVB3) entry on the adenylyl cycla se transmembrane signalling system. A significant decrease (by about 1 0-20%) was found in forskolin-augmented as well as in AlF4-- and GTP g amma S-sensitive adenylyl cyclase activity in plasma membranes isolate d 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 reconsti tute AC activity in the cyc(-) mutant of S49 cells was also reduced. C ontent of G-protein subunits, however, remained unchanged after CVB3 a ttachment. Functional alterations in the G-protein-mediated adenylyl c yclase signalling system were accompanied by a marked decrease (by abo ut 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 i n virus-sensitive cells as early as during the first period of its con tact with the cellular plasma membrane.