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. 2004 Jun;78(12):6489–6497. doi: 10.1128/JVI.78.12.6489-6497.2004

FIG. 3.

FIG. 3.

Identification of the regions of Stat3 and STP-A11 necessary for their interaction. (A) The central linker region of Stat3 is sufficient for interacting with STP-A11. Bacterially purified GST or GST fusion proteins containing the amino-terminal region (ΔCST3), the central linker region, or the carboxyl-terminal region (ΔNST3) of Stat3 were mixed with lysates of 293T cells transfected with the HA-tagged STP-A11 expression vector. Polypeptides present in GST beads were used for immunoblotting (IB) with an anti-HA (α-HA) antibody. Similar amounts of each GST fusion protein were used in this assay (data not shown). ND, N-terminal domain; TAD, transcriptional activation domain. (B) The amino-terminal region of STP-A11 is necessary for interacting with Stat3. Bacterially purified GST or GST fusion proteins containing the amino-terminal regions of STP-A11 were mixed with lysates of 293T cells transfected with the Stat3 expression vector. Polypeptides present in GST beads were used for immunoblotting with an anti-Stat3 antibody. Similar amounts of each GST fusion protein were used in this assay (data not shown). TM, transmembrane domain. (C) The amino-terminal proline-rich motif of STP-A11 is necessary for interacting with Stat3. At 48 h after transfection with a Stat3 expression vector together with an expression vector containing the HA-tagged wt STP-A11 or its mutant, 293T cells were lysed and used for immunoprecipitation with an anti-HA antibody, followed by immunoblotting with an anti-Stat3 antibody.