HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 NEF ASSOCIATES WITH A CELLULAR SERINE KINASE IN T-LYMPHOCYTES

With T-cell lines constitutively expressing Nef from the SF2 strain of human immunodeficiency virus type 1 (HIV-1(SF2)) in the form of a hybrid CDS-Nef fusion protein or T-cell lines chronically infected with HIV-1(SF2), a cellular serine kinase was found that specifically associates with Nef. Proteins of 62 kDa and 72 kDa, which coimmunoprecipitated with Nef, were phosphorylated in in vitro kinase assays. This Nef-associated serine kinase activity was not blocked by inhibitors of protein kinase C or protein kinase A and was lost when Nef was truncated at amino acid 94 or 99. These findings present evidence that a serine kinase activity is associated with Nef expressed in human T lymphocytes.