PHF11

PHF11 is a PHD finger-containing nuclear regulator that operates in two settings: transcriptional control of Th1 immune cytokines and the DNA double-strand break repair pathway (PMID:18405956, PMID:28115467). In T cells PHF11 resides constitutively in the cytoplasm and translocates to the nucleus upon T-cell activation, where it physically and functionally interacts with the p65 subunit of NF-κB, is recruited to the IFNG promoter, and enhances NF-κB DNA binding to drive transcription of the Th1 cytokines IFN-γ and IL-2 (PMID:18405956, PMID:20421878). Its PHD zinc-finger domain is required for this immune-regulatory function in vivo, as a point mutation in the domain dysregulates Il2 and NF-κB expression following LPS challenge (PMID:25091723). In a distinct genome-maintenance role, PHF11 localizes to sites of DNA damage and deprotected telomeres in S phase, where it complexes with the ssDNA-binding protein RPA and the 5' exonuclease EXO1; biochemically it stimulates EXO1 by relieving RPA-mediated inhibition, thereby promoting 5' end resection, ATR signaling, and homologous recombination, and protecting cells against DNA-damaging agents (PMID:28115467). PHF11 also participates in innate immune responses in non-immune cells, undergoing nuclear localization after TLR3 stimulation and restraining IL-8 production in keratinocytes (PMID:26573531).

1. 2008 Medium

   Established PHF11 as a positive transcriptional regulator of Th1 cytokines acting through NF-κB, defining its first molecular role.

   Evidence siRNA knockdown, overexpression, luciferase reporters, EMSA, and co-IP with p65/NF-κB in primary CD4+ and Jurkat T cells

   PMID:18405956

   Open questions at the time

   • No structure of the PHF11-p65 interaction
   • DNA-binding specificity from EMSA not mapped to a defined motif
   • No independent replication
2. 2010 Medium

   Showed that PHF11 function is regulated by activation-dependent cytoplasmic-to-nuclear translocation and direct promoter recruitment, explaining how it controls IFNG transcription.

   Evidence Subcellular fractionation, immunofluorescence, ChIP at the IFNG promoter, siRNA, and NF-κB reporter assays in T cells

   PMID:20421878

   Open questions at the time

   • Signal driving nuclear translocation not identified
   • Mechanism linking PHF11 to CD28 and GIMAP4/5 unresolved
   • Single lab
3. 2011 Medium

   Identified an allele-specific cis-regulatory mechanism controlling PHF11 expression, linking a transcription factor to disease-associated variation.

   Evidence EMSA showing allele-specific Oct-1 binding at SNP rs1046295 plus allele-specific expression allelotyping

   PMID:21320718

   Open questions at the time

   • No functional rescue or mutagenesis confirming causality
   • Phenotypic consequence of expression difference not established
4. 2014 Medium

   Provided in vivo genetic evidence that the PHD zinc-finger domain is required for PHF11's immune-regulatory role.

   Evidence ENU-induced PHD-domain point mutation in congenic mice, LPS stimulation, and RT-qPCR of Il2/NF-κB/Setdb2 in lung

   PMID:25091723

   Open questions at the time

   • Molecular function of the PHD domain (e.g. histone or DNA recognition) not defined
   • Single study
5. 2015 Medium

   Extended PHF11's function beyond T cells, implicating it in TLR3-driven innate immunity and cell cycle control in keratinocytes.

   Evidence siRNA, immunofluorescence, RT-qPCR/ELISA for IL-8/ISG15, and flow cytometry cell-cycle analysis after poly(I:C) stimulation

   PMID:26573531

   Open questions at the time

   • Direct targets in keratinocytes not mapped
   • Mechanism connecting PHF11 to claudin-1 distribution unknown
   • Single lab
6. 2017 High

   Defined a mechanistically distinct DNA repair function, showing PHF11 stimulates EXO1-mediated end resection by relieving RPA inhibition to enable HR.

   Evidence PICh telomere proteomics, siRNA with ATR/resection/HR assays, co-IP of PHF11-RPA and PHF11-EXO1, and in vitro reconstitution of EXO1 stimulation

   PMID:28115467

   Open questions at the time

   • How the PHD domain contributes to the repair function not established
   • Recruitment to damage sites not mechanistically dissected
   • Relationship between the transcriptional and repair roles unknown

• How a single PHD finger protein partitions between NF-κB-dependent transcription and RPA/EXO1-dependent DNA repair, and whether these roles are functionally linked, remains unresolved.
• No structure of PHF11 or its complexes
• Ligand/mark recognized by the PHD domain unknown
• Mechanism integrating immune and repair functions undefined