Retinoblastoma-associated proteins 46 and 48 (RBAP46 and RBAP48, also known as RBBP7 and RBBP4), were first identified in humancells as proteins that bind to retinoblastoma (Rb) tumor suppressor proteins. Since then, these proteins have been shown to be componentsof a number of protein complexes involved in chromatin regulation, including the chromatin assembly factor 1 (CAF-1) complex and the Btype histone acetyltransferase complex, HAT1, both of which are involved in chromatin assembly during DNA replication. RBAP46 andRBAP48 are also present in the nucleosome remodeling factor complex, NURF, and the nucleosome remodeling and histone deacetylationcomplex NuRD, and the Sin3/HDAC histone deacetylation complex. Recently, RBAP46 and RBAP48 were identified as components of thepolyribonucleic acid repressor complex PRC2, which also contains EED and Ezh2. RBAP46 and RBAP48 bind to the histone folding regionof histone H4 and are thought to target these chromatin remodeling, histone acetylation and histone deacetylation complexes to their histonesubstrates.
