Functions as an E3-type small ubiquitin-like modifier (SUMO) ligase, stabilizing the interaction between UBE2I and the substrate, and as a SUMO-tethering factor. Plays a crucial role as a transcriptional coregulation in various cellular pathways, including the STAT pathway and the steroid hormone signaling pathway. Involved in regulating STAT3 signaling via inhibiting STAT3 DNA-binding and suppressing cell growth. Enhances the sumoylation of MTA1 and may participate in its paralog-selective sumoylation.
[1]"SUMOylation and SUMO-interacting motif (SIM) of metastasis tumor antigen 1 (MTA1) synergistically regulate its transcriptional repressor function."Cong L., Pakala S.B., Ohshiro K., Li D.Q., Kumar R.J. Biol. Chem. 286:43793-43808(2011). [2]"Repression of the transactivating capacity of the oncoprotein PLAG1 by SUMOylation." Van Dyck F., Delvaux E.L.D., Van de Ven W.J.M., Chavez M.V.J. Biol. Chem. 279:36121-36131(2004). [3]"ATBF1 enhances the suppression of STAT3 signaling by interaction with PIAS3." Nojiri S., Joh T., Miura Y., Sakata N., Nomura T., Nakao H., Sobue S., Ohara H., Asai K., Ito M.Biochem. Biophys. Res. Commun. 314:97-103(2004).
