Rapid and transient phosphorylation of nuclear matrix proteins upon interferon-alpha treatment in Daudi lymphoma cells.

Evidence for a rapid and transient hyperphosphorylation of a 45 kD protein in isolated nuclei from interferon-α-treated Daudi lymphoma cells is presented. Extraction of nuclear matrices from these nuclei has provided further evidence for the association of such a protein in the nuclear matrix structure. Because phosphorylation assays performed directly on nuclear matrices from interferon-treated cells have revealed rapid and transient increase of γ32P-ATP incorporation into this 45 kD band, an early involvement of the nuclear matrix in the response of the nucleus to the interferon antiproliferative message is suggested.