Functional Importance of Stat3 Tetramerization in Activation of the α2-Macroglobulin Gene

Abstract

A tetrameric Stat3 complex was found to be essential in transfection experiments for maximal interleukin-6-inducible activation of α2-macroglobulin gene promoter. Stable tetramer formation of purified phosphorylated Stat3 was dependent on protein-protein interaction involving the N-terminal domain of Stat3. The functional importance of tetramer formation was shown by the decreased levels of transcriptional activation associated with hypomorphic mutations in N-terminal residues.