Histone demethylase that specifically demethylates ‘Lys-9’ and ‘Lys-36’ residues of histone H3, thereby playing a central role in histone code (PubMed:26741168). Does not demethylate histone H3 ‘Lys-4’, H3 ‘Lys-27’ nor H4 ‘Lys-20’. Demethylates trimethylated H3 ‘Lys-9’ and H3 ‘Lys-36’ residue, while it has no activity on mono- and dimethylated residues. Demethylation of Lys residue generates formaldehyde and succinate. Participates in transcriptional repression of ASCL2 and E2F-responsive promoters via the recruitment of histone deacetylases and NCOR1, respectively. ; [Isoform 2]: Crucial for muscle differentiation, promotes transcriptional activation of the Myog gene by directing the removal of repressive chromatin marks at its promoter. Lacks the N-terminal demethylase domain.
