SENP7

SENP7 is a SUMO2/3-specific isopeptidase that disassembles poly-SUMO2/3 chains and removes SUMO2/3 from conjugated substrates, acting as a deSUMOylation hub that links chromatin dynamics, innate immune signaling, and cellular metabolism (PMID:18799455, PMID:19392659). Crystallographic and biochemical work established that SENP7 strongly prefers SUMO2/3 over SUMO1, with rates comparable to SENP2 against di- and poly-SUMO2/3, and that a unique Loop1 insertion in the SENP6/SENP7 subclass forms an extensive interface with SUMO2 that confers isoform selectivity and supports poly-SUMO chain deconjugation (PMID:18799455, PMID:21878624, PMID:36334780). The full-length enzyme localizes predominantly to the nucleoplasm, where its depletion causes accumulation of high-molecular-mass SUMO2/3 conjugates (PMID:19392659). In chromatin, SENP7 is recruited through HP1α to deSUMOylate KAP1, controlling CHD3 association and enabling chromatin relaxation required for homologous recombination and resistance to DNA-damaging agents (PMID:24018422); a tandem HP1-interaction module additionally locks HP1 at pericentric heterochromatin to maintain its enrichment and proper mitotic progression (PMID:25660026). SENP7 deSUMOylates a broad substrate set that defines distinct cellular roles: cGAS, where SUMO removal relieves inhibition of DNA-binding and nucleotidyl-transferase activity to drive cGAS-STING/IRF3 innate immune output (PMID:28095500); PTEN, where ROS-triggered cytosolic translocation of SENP7 permits PTEN deSUMOylation, degradation, and sustained CD8+ T cell metabolic fitness and antitumor function (PMID:35143421); the transcriptional regulator Fli-I, coordinating Safb1 chromatin residency and MyHC-IId transcription for sarcomere assembly (PMID:36417853); and Plin4, promoting its lipid-droplet localization and adipocyte lipid droplet maturation (PMID:38677512). SENP7 protein levels are themselves set by ubiquitin ligases: SPOP-mediated degradation restrains SENP7 to promote senescence via HP1α SUMOylation, and SIAH2-mediated ubiquitination keeps SENP7 low in intestinal epithelium, with dysregulated SENP7 driving proinflammatory γδ T-cell expansion and gut inflammation (PMID:26527005, PMID:31825833).

1. 2008 High

   Established that SENP7 is a SUMO2/3-preferring isopeptidase structurally distinct from SENP1/2, defining its catalytic identity and chain-processing capacity.

   Evidence X-ray crystallography of the catalytic domain with in vitro deconjugation assays and structure-guided mutagenesis

   PMID:18799455

   Open questions at the time

   • No substrate-bound structure to explain isoform selectivity at this stage
   • Cellular substrates not yet identified
2. 2009 High

   Confirmed the SUMO2/3 chain-editing function in cells, showing SENP7 controls high-molecular-mass SUMO2/3 conjugate levels in the nucleoplasm.

   Evidence In vitro isopeptidase assays, siRNA knockdown, subcellular fractionation and immunofluorescence

   PMID:19392659

   Open questions at the time

   • Specific physiological substrates not defined
   • Mechanism of nucleoplasmic targeting unknown
3. 2011 High

   Identified the Loop1 insertion as the structural determinant of SUMO2/3 isoform specificity, explaining why SENP6/SENP7 favor SUMO2/3.

   Evidence Structure-based mutagenesis swapping SUMO surface residues with in vitro activity assays

   PMID:21878624

   Open questions at the time

   • Direct visualization of the Loop1-SUMO contacts awaited a complex structure
4. 2013 High

   Placed SENP7 in the DNA damage response by showing HP1α-bridged deSUMOylation of KAP1 enables chromatin relaxation and homologous recombination.

   Evidence Co-IP, siRNA knockdown, ChIP, HR repair and DNA damage sensitivity assays

   PMID:24018422

   Open questions at the time

   • Whether KAP1 deSUMOylation is direct or HP1α-dependent for catalysis not fully resolved
5. 2015 High

   Revealed a non-catalytic chromatin role: tandem HP1-interaction motifs lock HP1 at pericentric heterochromatin, coupling SENP7 to mitotic fidelity.

   Evidence FRAP live-cell imaging, knockdown, mutational analysis of HP1-interaction motifs, mitotic timing

   PMID:25660026

   Open questions at the time

   • Relationship between the locking function and deSUMOylase activity unclear
6. 2015 High

   Showed SENP7 abundance is controlled by SPOP-mediated ubiquitination, linking its turnover to senescence through HP1α SUMOylation.

   Evidence Co-IP, ubiquitination assays, wild-type/mutant SPOP expression, senescence assays

   PMID:26527005

   Open questions at the time

   • Generality of SPOP control across tissues not established
7. 2015 Medium

   Extended SENP7 substrate range to c-Myc, positioning deSUMOylation upstream of RNF4-mediated proteasomal control of c-Myc.

   Evidence siRNA knockdown, mass spectrometry of SUMO acceptor lysines, SUMOylation assays

   PMID:25895136

   Open questions at the time

   • No direct in vitro reconstitution of SENP7 acting on c-Myc
   • Functional consequence for c-Myc target genes not shown
8. 2017 High

   Defined a positive role for SENP7 in innate immunity by deSUMOylating cGAS to relieve SUMO-mediated suppression of its catalytic and DNA-binding activities.

   Evidence Co-IP, site-directed mutagenesis of cGAS SUMO sites, in vitro nucleotidyl-transferase assay, IRF3 reporter

   PMID:28095500

   Open questions at the time

   • In vivo immune consequence of SENP7 loss not addressed in this study
9. 2017 Medium

   Demonstrated a maternal requirement for SENP7 in meiotic progression and the maternal-zygotic transition.

   Evidence siRNA microinjection in mouse oocytes, immunofluorescence, live imaging, chromatin staining

   PMID:28315713

   Open questions at the time

   • Direct SUMO substrates driving meiotic phenotypes not identified
   • Causal link between histone modification changes and spindle defects unresolved
10. 2019 Medium

    Showed SIAH2-mediated ubiquitination restrains SENP7 in intestinal epithelium, with dysregulated SENP7 driving proinflammatory γδ T-cell expansion in IBD.

    Evidence Co-IP, ubiquitination assay, in vivo knockdown, flow cytometry, DSS colitis model

    PMID:31825833

    Open questions at the time

    • SENP7 substrates underlying the inflammatory interactome not defined
    • Mechanism linking epithelial SENP7 to γδ T cells incomplete
11. 2022 High

    Linked SENP7 to T-cell metabolism by showing ROS-triggered cytosolic translocation enables PTEN deSUMOylation and degradation to sustain CD8+ T-cell fitness and antitumor activity.

    Evidence Conditional KO mice, metabolic assays, Co-IP, subcellular fractionation, tumor models, human CRC samples

    PMID:35143421

    Open questions at the time

    • Signal that triggers SENP7 cytosolic translocation upon ROS not defined
    • Whether nuclear functions are concurrently affected unclear
12. 2022 High

    Provided the SENP7:SUMO2 co-crystal structure, directly visualizing Loop1 contacts that explain SUMO2 isoform specificity.

    Evidence X-ray crystallography of the catalytic domain bound to SUMO2 with family comparison

    PMID:36334780

    Open questions at the time

    • No structure with a physiological poly-SUMO substrate
13. 2022 High

    Established a transcriptional/sarcomere role: SENP7 deSUMOylates Fli-I to promote Safb1 chromatin residency and MyHC-IId transcription for muscle contraction.

    Evidence SENP7 KO muscle cells, ChIP, Co-IP, SUMOylation assay, contraction and chromatin conformation analyses

    PMID:36417853

    Open questions at the time

    • How cachexia signaling impedes the SENP7 program mechanistically unresolved
14. 2024 High

    Showed SENP7 deSUMOylates Plin4 to drive its lipid-droplet localization, defining a role in adipocyte lipid droplet maturation.

    Evidence Conventional and adipocyte-specific KO mice, lipid droplet morphology, SUMOylation assay, Co-IP

    PMID:38677512

    Open questions at the time

    • Whether SENP7 acts at the lipid droplet itself or upstream in the cytosol not defined
15. 2025 Medium

    Implicated SENP7-driven deSUMOylation of cGAS and IFI204 in microglial STING activation and pyroptosis in neuroinflammation.

    Evidence Co-IP, SUMOylation assays, siRNA knockdown, molecular docking, co-culture in BV2/microglial models

    PMID:39999677 PMID:40407969

    Open questions at the time

    • IFI204 interaction relies partly on docking without structural validation
    • Limited mechanistic depth on deSUMOylation kinetics in these contexts
16. 2026 Medium

    Extended SENP7 function to regulatory B-cell biology via deSUMOylation-dependent activation of SIRT1 and IL-10 expression.

    Evidence Co-IP, flow cytometry, adoptive transfer, primary cell sorting

    PMID:41362746

    Open questions at the time

    • Direct deSUMOylation of SIRT1 not biochemically reconstituted
    • SIRT1 SUMO sites not mapped

• How SENP7 substrate selection and subcellular partitioning are coordinated across its diverse roles (chromatin, immunity, metabolism) remains unresolved.
• No unifying model for context-specific substrate recognition
• Regulators governing nuclear vs cytosolic localization beyond ROS not defined
• No structure of SENP7 engaging a full-length physiological substrate