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. {ECO:0000269|PubMed:14716005; ECO:0000269|PubMed:15866867; ECO:0000269|PubMed:19081374}.