SMARCA2

SMARCA2 (also known as BRM) encodes one of the two mutually exclusive ATPase catalytic subunits of the mammalian SWI/SNF (BAF) chromatin-remodeling complex and regulates transcription through ATP-dependent modulation of chromatin accessibility and nucleosome positioning^[1][2]. Mechanistically, SMARCA2 provides the enzymatic activity required for chromatin remodeling, thereby influencing gene-expression programs linked to cellular differentiation, proliferation, and lineage-specific transcriptional control^[1][3]. Within the BAF complex, SMARCA2 functions in a paralogous relationship with SMARCA4 (BRG1), and either ATPase can support remodeling activity; however, the two proteins are incorporated in mutually exclusive complexes and can regulate distinct transcriptional programs despite substantial functional overlap^[2][4]. This distinction has important disease implications because loss of SMARCA4 frequently creates a dependency on residual SMARCA2 activity, establishing a synthetic-lethal relationship that has been validated in multiple cancer models^[4][5][6]. In developmental disease, recurrent SMARCA2 mutations are associated with Nicolaides-Baraitser syndrome, highlighting a nonredundant role in human development and enhancer regulation^[3][7]. For experimental applications, increasing attention has focused on pharmacologic inhibition or targeted degradation of SMARCA2, particularly in SMARCA4-deficient tumors, where selective suppression of SMARCA2 produces antitumor effects and provides a tractable strategy for studying SWI/SNF ATPase dependence^[5][6][8]. Studies further indicate that the ATPase domain represents a more effective therapeutic target than bromodomain inhibition alone in SWI/SNF-mutant cancer settings^[6].