FIGURE 8.

Possibility of self-association of Mycd WT and MRTF-A. A and B, differences in the binding affinities of Mycd WT and Mycd ΔN128 for Mycd N128 (A) and the less significant possibility of MRTF-A self-association (B). Mixtures of the indicated FLAG-tagged and HA-tagged Mycd or MRTF-A were subjected to IP analyses. C, mapping of the functional domain in Mycd WT for the interaction with Mycd N128. Mixtures of HA-tagged Mycd N128 and each indicated FLAG-tagged Mycd were subjected to IP analyses as described in the legend for Fig. 1. The respective IP/IB signal intensities were quantified as described under “Experimental Procedures.” The percentages indicated at the top of the gels indicate relative binding affinities for Mycd N128 normalized by the affinity of Mycd ΔN128, which was at 100%. Results are means ± S.E. of three independent experiments. D, effect of SRF on Mycd WT self-association. The binding of Mycd ΔN128 to Mycd N128 was examined in the absence or presence of SRF (left). Mixtures of the indicated tagged proteins with or without Myc-tagged SRF were subjected to IP analysis. The relative binding affinities of Mycd ΔN128 for Mycd N128 are indicated at the top of the gels; affinity in the absence of SRF was set at 100%. The interaction between SRF and Mycd ΔN128 is shown (right). Mixtures of the indicated tagged proteins were immunoprecipitated with anti-Myc antibody and protein A-Sepharose. The resulting immunoprecipitates were analyzed by IB using the indicated antibodies.