FIGURE 9.

Requirement for the coactivator PAS-B domain for efficient recruitment by ERα. ³⁵S-Radiolabeled versions of SRC1 (codons 1–781) and SRC1 (codons 595–781) were mixed together and incubated with immobilized GST-ERα in the presence of increasing E2, using the same general protocol as described in the legend to Fig. 4E. The SRC1-(1–781) and SRC1-(595–781) coactivator proteins bound by the GST-ERα were eluted, resolved from one another by SDS-PAGE, quantified, and are presented as the percent of their input values. A, stabilization of SRC1 recruitment by the coactivator N-terminal domain. B, mapping of the stabilizing function to the SRC1 PAS-B domain. Statistical confidence symbols are as described in the legend to Fig. 3.