Interferon activation of the transcription factor stat91 involves dimerization through SH2-phosphotyrosyl peptide interactions

The monomeric nature of the inactive Stat-91, a 91 kd protein that functions as a signal transducer and activator of transcription, in the cytoplasm of untreated cells is confirmed. A stable homodimer results from interferon gamma-induced phosphorylation. SH2-phosphotyrosyl peptide interactions mediate dimerization of Stat-91.