In mammals, the CoREST complex is a chromatin-modifying structure that, through interactions with NRSF (neuron restrictive silencer factor), regulates neuronal gene expression and neuronal cell fate. RCOR2 (REST corepressor 2) and RCOR3 (REST corepressor 3) are nuclear proteins that each contain one ELM2 domain and two SANT domains. RCOR2 and RCOR3, both members of the CoREST family, are thought to function as components of the CoREST complex; possibly playing a role in the transcriptional repression of neuronal genes. Additionally, RCOR2 and RCOR3, in conjunction with CoREST, can form immunocomplexes with a variety of histone-modifying genes, including G9a and HDAC1. Via these protein complexes, RCOR2 and RCOR3 can further regulate transcription by controlling the methylation and demethylation of target genes during early development. While RCOR2 is expressed as only one known isoform, RCOR3 exists as two isoforms due to alternative splicing events.