LZTS2

LZTS2 is a tumor suppressor that restrains Wnt/β-catenin signaling by directly binding β-catenin and exporting it from the nucleus through a C-terminal CRM1-dependent nuclear export signal, thereby repressing β-catenin-mediated transactivation (PMID:17000760). This regulatory function is conserved and operates in vivo: loss of Lzts2 in zebrafish and knockout mice alters β-catenin localization and amplifies Wnt-induced transcription, with developmental consequences for dorsoventral patterning and kidney/urinary tract morphogenesis (PMID:22057270, PMID:21949185). In parallel, LZTS2 inhibits PI3K/AKT signaling by binding the regulatory subunit p85 and competing with the catalytic p110 subunit, an interaction required for its suppression of tumorigenesis and radioresistance (PMID:29409973). Beyond signaling, LZTS2 governs microtubule and cytokinetic control: it localizes to centrosomes and midbodies, directly inhibits p80 katanin-mediated microtubule severing, negatively regulates centrosomal CEP135 and microtubule nucleation, and acts as a mechanosensitive effector of α-catenin at adherens junctions to ensure cytokinetic fidelity, with its loss causing binucleation and cytokinesis failure (PMID:17351128, PMID:18490357, PMID:39786338, PMID:40521914). LZTS2 abundance and activity are tightly controlled post-translationally by multiple E3 ligases and kinases—β-TrCP/CK1δ, CCDC137-recruited β-TrCP, SPOP (opposed by the deubiquitinase HAUSP), and SH3RF2 drive its degradation, while PLK1 phosphorylation at Ser451 disrupts its β-catenin interaction without affecting stability—thereby derepressing both Wnt and PI3K/AKT signaling in cancer (PMID:33420362, PMID:38918619, PMID:38740232, PMID:41436424, PMID:40676695).

1. 2006 High

   Established the core molecular mechanism by which LZTS2 antagonizes Wnt signaling, answering how it controls β-catenin: through direct binding and active CRM1-dependent nuclear export.

   Evidence Co-IP, GFP-localization, NES point mutagenesis and leptomycin B treatment in SW480 cells

   PMID:17000760

   Open questions at the time

   • Did not define the β-catenin-binding domain of LZTS2
   • Did not address whether export is regulated by upstream signals
2. 2007 High

   Extended LZTS2 beyond transcriptional control into mitosis, showing it regulates cytokinesis through interaction with p80 katanin at centrosomes and midbodies.

   Evidence Immunofluorescence co-localization, RNAi, overexpression, and caspase-inhibitor rescue

   PMID:17351128

   Open questions at the time

   • Did not establish whether katanin regulation is direct
   • Binucleation mechanism not resolved at this stage
3. 2007 Medium

   Connected LZTS2 to a second signaling axis, demonstrating it mediates cross-regulation between β-catenin/Tcf and NF-κB pathways.

   Evidence RNAi knockdown with nuclear fractionation and NF-κB/Tcf reporter assays in human mesenchymal stem cells

   PMID:17950943

   Open questions at the time

   • Direct versus indirect NF-κB regulation not distinguished
   • β-TrCP1 induction mechanism not mechanistically dissected
4. 2008 High

   Provided the biochemical basis for LZTS2's cytoskeletal role, showing direct inhibition of katanin severing and stabilization of microtubules that restrains cell motility.

   Evidence In vitro microtubule severing reconstitution, live-cell microtubule tracing, RNAi, and ninein rescue

   PMID:18490357

   Open questions at the time

   • Link between microtubule stabilization and tumor suppression not directly tested
   • Domain mediating katanin inhibition only broadly localized to C-terminus
5. 2009 Medium

   Revealed a neuronal, activity-dependent dimension of LZTS2 function, coupling synaptic NMDA receptor activation to β-catenin nuclear shuttling and target gene transcription.

   Evidence Reciprocal Co-IP, NMDA stimulation, and transcriptional reporter assays at the postsynaptic density

   PMID:19703901

   Open questions at the time

   • Single lab; physiological relevance of nuclear co-migration in neurons not independently confirmed
   • Role of Shank3/SPAR1 binding in regulating β-catenin export unresolved
6. 2011 High

   Validated LZTS2's Wnt-regulatory function in vivo across vertebrates, placing it downstream of Wnt and upstream of BMP in patterning and confirming its requirement for normal development.

   Evidence Zebrafish morpholino/mRNA epistasis with Co-IP, and Lzts2 knockout mouse with β-catenin localization and reporter assays

   PMID:21949185 PMID:22057270

   Open questions at the time

   • Tissue-specific contributions of LZTS2 in mammalian development not dissected
   • Cytoskeletal versus transcriptional contributions to phenotypes not separated
7. 2018 High

   Identified a distinct tumor-suppressive mechanism, showing LZTS2 inhibits PI3K/AKT signaling by competing with p110 for the p85 regulatory subunit.

   Evidence Unbiased co-IP/MS, competitive binding assay, and rescue experiments in nasopharyngeal carcinoma cells and xenografts

   PMID:29409973

   Open questions at the time

   • Structural basis of p85 competition not defined
   • Crosstalk between LZTS2's Wnt and PI3K functions unexplored
8. 2021 High

   Defined how LZTS2 levels are controlled, identifying it as a CK1δ-phosphorylated, β-TrCP-ubiquitinated substrate whose degradation activates PI3K/AKT and drives HCC progression.

   Evidence Co-IP, ubiquitination and kinase assays with in vitro and in vivo functional validation

   PMID:33420362

   Open questions at the time

   • Phospho-degron sequence not pinpointed
   • Whether the same degradation controls Wnt output not tested here
9. 2024 High

   Refined the degradation mechanism by identifying an adaptor and a specific ubiquitination site, showing CCDC137 recruits β-TrCP for nuclear K48 poly-ubiquitination of LZTS2 at K467.

   Evidence K48-linkage ubiquitination assays, domain mapping, peptide disruption, HCC organoids and PDX models

   PMID:38918619

   Open questions at the time

   • Signals controlling CCDC137-LZTS2 engagement unknown
   • Relationship to CK1δ phosphorylation not integrated
10. 2024 Medium

    Distinguished phospho-regulation of LZTS2 activity from stability, showing PLK1 phosphorylation at Ser451 disrupts β-catenin binding to activate Wnt without degrading LZTS2.

    Evidence Co-IP, Ser451 mutagenesis, and β-catenin nuclear localization and functional assays

    PMID:38740232

    Open questions at the time

    • Direct kinase assay detail limited
    • Cell-cycle context of PLK1-LZTS2 regulation not defined
11. 2025 Medium

    Expanded the regulatory network with additional opposing enzymes, showing SPOP and SH3RF2 degrade LZTS2 while HAUSP stabilizes it, collectively tuning Wnt activity in cancer.

    Evidence Ubiquitination/deubiquitination and competitive binding assays in colorectal cancer cells; proteomic interaction and ubiquitination with in vivo tumor assays for SH3RF2

    PMID:40676695 PMID:41436424

    Open questions at the time

    • Whether these ligases act in distinct tissues or compete is unclear
    • SPOP/HAUSP binding region overlap mapped only coarsely
12. 2025 High

    Unified LZTS2's mitotic roles by placing it within junctional mechanosensing and centrosomal nucleation control, establishing it as an α-catenin effector required for cytokinetic fidelity and an upstream regulator of CEP135.

    Evidence α-catenin KO/reconstitution and M-domain mutagenesis with proximity labeling in MDCK cells; RNAi epistasis and centrosomal nucleation assays

    PMID:39786338 PMID:40521914

    Open questions at the time

    • How junctional sequestration of LZTS2 integrates with its katanin/CEP135 functions unresolved
    • Mechanism linking α-catenin tension to LZTS2 release not biochemically defined
13. 2026 Medium

    Identified a developmental genetic interaction, showing LZTS2 and DYRK1A cooperate during craniofacial and neural crest morphogenesis.

    Evidence Xenopus morpholino/mRNA epistasis with in situ hybridization for sox9/pax3 (preprint)

    PMID:41959346

    Open questions at the time

    • Preprint not yet peer-reviewed
    • Molecular basis of the LZTS2-DYRK1A interaction undefined
    • Whether interaction occurs through Wnt or a distinct pathway unknown

• How LZTS2's multiple activities—β-catenin export, PI3K inhibition, microtubule/cytokinesis control, and junctional mechanosensing—are coordinated within a single cell, and which dominate in specific tissues, remains unresolved.
• No integrated structural model of LZTS2 domains and their respective binding partners
• Spatial/temporal partitioning of LZTS2 between nucleus, centrosome, midbody, and junctions not defined
• Whether degradation by the various E3 ligases is tissue- or context-specific is unknown