ASSOCIATION OF ERK2 MITOGEN-ACTIVATED PROTEIN-KINASE WITH HUMAN-IMMUNODEFICIENCY-VIRUS PARTICLES

Here we report the presence of a protein kinase activity associated wi th human immunodeficiency virus type 1 (HIV-1) particles. We observed phosphorylation of five major proteins by the endogenous protein kinas e activity. Phosphoamino acid analysis revealed phosphorylated serine and threonine residues. In addition, we observed autophosphorylation o f two proteins in the presence of gamma-ATP in an in-gel phosphorylati on assay. These two proteins are not linked by a disulfide bond, sugge sting that two different protein kinases are associated with HIV-1 vir ions. Our results indicate the presence of ERK2 mitogen-activated prot ein kinase and of a 53,000-molecular-weight protein kinase associated with virions. Moreover, the use of different HIV strains derived from T cells and promonocytic cells, as well as the use of human T-cell leu kemia virus type 1 particles, demonstrates that ERK2 is strongly assoc iated with retrovirus particles in a cell-independent manner, Exogenou s substrates, such as histone proteins, and a viral substrate, such as Gag protein, are phosphorylated by virus-associated protein kinases.