MYOSIN-ACTIN INTERACTION PLAYS AN IMPORTANT ROLE IN HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 RELEASE FROM HOST-CELLS

We examined the potential role of myosin and actin in the release of h uman immunodeficiency virus type 1 (HIV-1) from infected cells. Wortma nnin (100 nM to 5 mu M), an effective inhibitor of myosin light chain kinase, blocked the release of HIV-I from infected T-lymphoblastoid an d monocytoid cells in a concentration-dependent manner. Cytochalasin D , a reagent that disrupts the equilibrium between monomeric and polyme ric actin, also partially inhibited the release of HIV-1 from the infe cted cells. At the budding stage, myosin and HIV-1 protein were detect ed in the same areas on the plasma membrane by using dual-label immuno fluorescence microscopy and immunoelectron microscopy. In the presence of 5 mu M wortmannin, viral components were observed on the plasma me mbrane by using immunofluorescence microscopy and electron microscopy, implying that wortmannin did not disturb the transport of viral prote ins to the plasma membrane but rather inhibited budding.