Fig. 3.
Effect of Tat on tyrosine phosphorylation.
Tat effect on tyrosine phosphorylation of Flk-1 (A) and Flt-1 (B), and on MAP kinase activity (C). (A and B) Total cell lysates were immunoprecipitated with the indicated antibodies, then subjected to Western blot analysis with antiphosphotyrosine antibody (PY99) (upper panels) or with the indicated antibodies (lower panels). (C) Lysates from HMVEC-Ls stimulated for the indicated times were immunoprecipitated with monoclonal antibodies against Erk 1/2, and the precipitates were incubated at room temperature for 30 minutes in kinase assay buffer containing [γ32P]-ATP, along with MBP. Incorporation of 32P into MBP was analyzed on 12% SDS-PAGE and visualized by autoradiography.