Jumonji C domain containing histone demethylase 1F
PHD finger protein 8
Histone lysine demethylase with selectivity for the di-and monomethyl states that plays a key role cell cycle progression, rDNA transcription and brain development. Demethylates mono- and dimethylated histone H3 'Lys-9' residue (H3K9Me1 and H3K9Me2), dimethylated H3 'Lys-27' (H3K27Me2) and monomethylated histone H4 'Lys-20' residue (H4K20Me1). Acts as a transcription activator as H3K9Me1, H3K9Me2, H3K27Me2 and H4K20Me1 are epigenetic repressive marks. Involved in cell cycle progression by being required to control G1-S transition. Acts as a coactivator of rDNA transcription, by activating polymerase I (pol I) mediated transcription of rRNA genes. Required for brain development, probably by regulating expression of neuron-specific genes. Only has activity toward H4K20Me1 when nucleosome is used as a substrate and when not histone octamer is used as substrate. May also have weak activity toward dimethylated H3 'Lys-36' (H3K36Me2), however, the relevance of this result remains unsure in vivo. Specifically binds trimethylated 'Lys-4' of histone H3 (H3K4me3), affecting histone demethylase specificity: has weak activity toward H3K9Me2 in absence of H3K4me3, while it has high activity toward H3K9me2 when binding H3K4me3.
Involvement in disease
Defects in PHF8 are the cause of mental retardation syndromic X-linked Siderius type (MRXSSD) [MIM:300263]. A disorder characterized by mild to borderline mental retardation with or without cleft lip/cleft palate.
Belongs to the JHDM1 histone demethylase family. JHDM1D subfamily. Contains 1 JmjC domain. Contains 1 PHD-type zinc finger.
The PHD-type zinc finger mediates the binding to H3K4me3. Binding to H3K4me3 promotes its access to H3K9me2. The linker region is a critical determinant of demethylase specificity. It enables the active site of JmjC to reach the target H3K9me2 when the PHD-type zinc finger binds to H3K4me3.
Phosphorylation at Ser-69 and Ser-120 are required for dissociation from chromatin and accumulation of H4K20Me1 levels during prophase.
Nucleus. Nucleus > nucleolus. Recruited to H3K4me3 sites on chromatin during interphase. Dissociates from chromatin when cells enter mitosis.