ATP-dependent chromatin remodelers

Human SWI/SNF ATPases bind acetylated nucleosomes through the bromodomains of their two alternative catalytic subunits, SMARCA2 (also known as BRM) or SMARCA4 (BRG1) (Hassan et al, 2002; Singh et al, 2006; Singh et al, 2007; reviewed in Euskirchen et al 2012). Histone and DNA contacts are also mediated by other protein components of the SWI/SNF complex (reviewed in Euskirchen et al, 2012; Cenik and Shilatifard, 2021). SWI/SNF chromatin remodellers are generally involved in gene activation or repression and provide access to chromatin by repositioning or ejecting nucleosomes (reviewed in Eustermann et al, 2024).

Human CHD family ATPases contain one of nine catalytic CHD protein paralogs. DNA-binding is mediated by contacts between methylated histones and the chromodomain of CHD1-9, as well as through other protein constituents of the ATPase complex (Bannister et al, 2001; Lachner et al, 2001; Flanagan et al, 2005; Sims et al, 2005; reviewed in Eustermann et al, 2024). CHD family ATPases are involved in diverse chromatin remodelling activities, including nucleosome assembly and spacing, access to regulatory elements and changes to histone composition (reviewed in Clapier et al, 2017).

Human ISWI family ATPases contain one of two potential catalytic subunits, SMARCA5 (also known as SNF2H) or SMARCA1 (SNF2L), that interact with unmodified histone tails through their SANT domains. ISWI complexes are generally involved in nucleosome maturation and regulation of spacing and assembly, often resulting in repressive gene states, but some are also involved in transcriptional activation (Xiao et al, 2001; reviewed in Clapier et al, 2017; Eustermann et al, 2024).

Human INO80 family ATPases contain one of three catalytic subunits, INO80, SRCAP or EP400. INO80 complexes generally contribute more to histone exchange than to nucleosome spacing, assembly or access (reviewed in Clapier et al, 2017; Eustermann et al, 2024).