Transcriptional activator which is required for calcium-dependent dendritic growth and branching in cortical neurons. Recruits CREB-binding protein (CREBBP) to nuclear bodies. Component of the CREST-BRG1 complex, a multiprotein complex that regulates promoter activation by orchestrating a calcium-dependent release of a repressor complex and a recruitment of an activator complex. In resting neurons, transcription of the c-FOS promoter is inhibited by BRG1-dependent recruitment of a phospho-RB1-HDAC1 repressor complex. Upon calcium influx, RB1 is dephosphorylated by calcineurin, which leads to release of the repressor complex. At the same time, there is increased recruitment of CREBBP to the promoter by a CREST-dependent mechanism, which leads to transcriptional activation. The CREST-BRG1 complex also binds to the NR2B promoter, and activity-dependent induction of NR2B expression involves a release of HDAC1 and recruitment of CREBBP. Homodimer. Dimerization may be necessary for its function in neuronal dendritic development. Interacts (via C-terminus) with CREBBP (via N-terminus), EP300 and SMARCA4/BRG1. Interacts with the nBAF complex. Association with CREBBP facilitates transcription while the association with SMARCA4/BRG1 suppresses CREST-mediated transcription in resting neurons (By similarity). Localizes to nuclear bodies. Colocalizes with SGO1 at kinetochore (By similarity). The MFD (multi-functional domain) domain is involved in transcription transactivation, nuclear body targeting and dimerization. Mice are smaller than littermates and show coordination defects. There is increased mortality in beginning at about P14, and about 80% die by P28. Less than 20% survive to adulthood, and they are infertile. Belongs to the SS18 family.