FIG. 6.

Mapping of the protein-protein interaction domains in GATA4 and JMJ. Various ³⁵S-labeled GATA4 mutants (A) were incubated with approximately 1 μg of GST-JMJ 529-792 fusion proteins coupled to agarose beads and were then subjected to SDS-PAGE (B). A diagram of protein structures for the GATA4 mutants and a summary of the physical interaction are shown (C). The asterisks in panel C indicate the positions of the point mutations (26). For converse experiments, various ³⁵S-labeled JMJ mutants (D) were incubated with approximately 1 μg of GST-GATA4 beads or GST beads, as indicated, followed by SDS-PAGE (E). A diagram of protein structures for JMJ mutants and the summary are shown (F); the a indicates the binding activity of the GST-JMJ 529-792 to ³⁵S-GATA4 as shown in panels B and C. Association affinity: ++, strong interaction; +, moderate interaction; −, no interaction. G, GATA4; J, JMJ; wt, wild type.