UHRF1
Developmental stage
Expressed in fetal thymus, liver and kidney.
Domain
The tudor-like regions specifically recognize and bind histone H3 unmethylated at 'Arg-2' (H3R2me0), while the PHD-type zinc finger specifically recognizes and binds histone H3 trimethylated at 'Lys-9' (H3K9me3). The tudor-like regions simultaneously recognizes H3K9me3 through a conserved aromatic cage in the first tudor-like subdomain and unmodified H3K4 (H3K4me0) within a groove between the tandem subdomains (PubMed:21489993, PubMed:21777816, PubMed:22100450). The linker region plays a role in the formation of a histone H3-binding hole between the reader modules formed by the tudor-like regions and the PHD-type zinc finger by making extended contacts with the tandem tudor-like regions (PubMed:22837395).
The YDG domain (also named SRA domain) specifically recognizes and binds hemimethylated DNA at replication forks (DNA that is only methylated on the mother strand of replicating DNA) (PubMed:17673620). It contains a binding pocket that accommodates the 5-methylcytosine that is flipped out of the duplex DNA. 2 specialized loops reach through the resulting gap in the DNA from both the major and the minor grooves to read the other 3 bases of the CpG duplex. The major groove loop confers both specificity for the CpG dinucleotide and discrimination against methylation of deoxycytidine of the complementary strand (PubMed:18772889). The YDG domain also recognizes and binds 5-hydroxymethylcytosine (5hmC) (PubMed:21731699).
The RING finger is required for ubiquitin ligase activity.
Function
Multidomain protein that acts as a key epigenetic regulator by bridging DNA methylation and chromatin modification. Specifically recognizes and binds hemimethylated DNA at replication forks via its YDG domain and recruits DNMT1 methyltransferase to ensure faithful propagation of the DNA methylation patterns through DNA replication. In addition to its role in maintenance of DNA methylation, also plays a key role in chromatin modification: through its tudor-like regions and PHD-type zinc fingers, specifically recognizes and binds histone H3 trimethylated at 'Lys-9' (H3K9me3) and unmethylated at 'Arg-2' (H3R2me0), respectively, and recruits chromatin proteins. Enriched in pericentric heterochromatin where it recruits different chromatin modifiers required for this chromatin replication. Also localizes to euchromatic regions where it negatively regulates transcription possibly by impacting DNA methylation and histone modifications. Has E3 ubiquitin-protein ligase activity by mediating the ubiquitination of target proteins such as histone H3 and PML. It is still unclear how E3 ubiquitin-protein ligase activity is related to its role in chromatin in vivo. Plays a role in DNA repair by cooperating with UHRF2 to ensure recruitment of FANCD2 to interstrand cross-links (ICLs) leading to FANCD2 activation. Acts as a critical player of proper spindle architecture by catalyzing the 'Lys-63'-linked ubiquitination of KIF11, thereby controlling KIF11 localization on the spindle (PubMed:37728657).
Involvement in disease
Defects in UHRF1 may be a cause of cancers. Overexpressed in many different forms of human cancers, including bladder, breast, cervical, colorectal and prostate cancers, as well as pancreatic adenocarcinomas, rhabdomyosarcomas and gliomas. Plays an important role in the correlation of histone modification and gene silencing in cancer progression. Expression is associated with a poor prognosis in patients with various cancers, suggesting that it participates in cancer progression.
Pathway
Protein modification; protein ubiquitination.
Post-translational modifications
Phosphorylation at Ser-298 of the linker region decreases the binding to H3K9me3. Phosphorylation at Ser-639 by CDK1 during M phase impairs interaction with USP7, preventing deubiquitination and leading to degradation by the proteasome.
Ubiquitinated; which leads to proteasomal degradation. Autoubiquitinated; interaction with USP7 leads to deubiquitination and prevents degradation. Ubiquitination and degradation takes place during M phase, when phosphorylation at Ser-639 prevents interaction with USP7 and subsequent deubiquitination. Polyubiquitination may be stimulated by DNA damage.
Tissue Specificity
Expressed in thymus, bone marrow, testis, lung and heart. Overexpressed in breast cancer.
Cellular localization
- Nucleus
- Associated, through the YDG domain (also called SRA domain), with replicating DNA from early to late S phase, including at replicating pericentric heterochromatin (By similarity). Also localizes to euchromatic regions. In non-S-phase cells, homogenously distributed through the nucleus (By similarity).
Alternative names
ICBP90, NP95, RNF106, UHRF1, E3 ubiquitin-protein ligase UHRF1, Inverted CCAAT box-binding protein of 90 kDa, Nuclear protein 95, Nuclear zinc finger protein Np95, RING finger protein 106, RING-type E3 ubiquitin transferase UHRF1, Transcription factor ICBP90, Ubiquitin-like PHD and RING finger domain-containing protein 1, Ubiquitin-like-containing PHD and RING finger domains protein 1, HuNp95, hNp95, hUHRF1