ANKHD1

ANKHD1 is a large multi-domain scaffolding protein that promotes cell proliferation, cell-cycle progression, and tumor cell migration across diverse cancer contexts by coupling protein-protein and RNA-binding activities to growth-control pathways (PMID:24726915, PMID:29695508). It acts upstream of the Hippo effector YAP1, with silencing reducing YAP1 expression and activation while increasing inhibitory YAP1 phosphorylation, and YAP1 re-expression rescues the loss-of-ANKHD1 phenotype, placing ANKHD1 within a YAP1/AKT signaling axis that controls EMT markers and radioresistance (PMID:24726915, PMID:30555746, PMID:35110552). ANKHD1 drives the cell cycle through several converging routes: it represses the p21 (CDKN1A) promoter and binds p21 directly while shuttling between cytoplasm and nucleus (PMID:25483783), binds CDK4 to potentiate Cyclin D1/CDK4 activity and retinoblastoma phosphorylation (PMID:40457431), and uses its C-terminal KH domain to bind and suppress tumor-suppressor miRNAs (miR-29a, miR-205, miR-196a), relieving repression of Cyclin D1 (PMID:29695508). As a chromatin-associated cofactor it partners with the methyltransferase SMYD3 to activate transcription of SLUG and CDK2 in association with active histone marks, promoting migration, invasion, and chemoresistance (PMID:30646949, PMID:33773404), and it interacts with RBM39 to regulate MKI67 pre-mRNA splicing, with its own expression epigenetically induced via p300-mediated H3K27ac (PMID:42061695). Independently of these growth functions, the ankyrin repeat domain dimerizes and deforms membranes into tubules and vesicles, contributing to negative regulation of early endosome enlargement (PMID:31255983). Additional reported activities include scaffolding with SHP2, interaction with SIVA to engage the Stathmin 1 pathway, and antiapoptotic regulation of caspases by a KH-domain-deficient splice variant (PMID:16956752, PMID:16098192, PMID:25523139).

1. 2005 Medium

   Established that ANKHD1 (via its KH-domain-lacking splice variant VBARP) has a cell-survival function, the first functional readout for the gene.

   Evidence siRNA knockdown with caspase activity assays and biochemical fractionation

   PMID:16098192

   Open questions at the time

   • Mechanism linking ANKHD1 to caspase regulation not defined
   • Full-length ANKHD1 vs splice variant roles not separated
2. 2006 Medium

   Identified ANKHD1 as a SHP2-associated protein in cytosolic and membrane fractions, framing it as a scaffolding protein.

   Evidence Subcellular fractionation and co-immunoprecipitation in K562 and LNCaP cells

   PMID:16956752

   Open questions at the time

   • Reciprocal Co-IP not shown
   • Functional consequence of the SHP2 association untested
3. 2012 Medium

   Showed ANKHD1 promotes cell-cycle progression by suppressing the CDK inhibitor p21, defining its first cell-cycle mechanism.

   Evidence Lentiviral shRNA knockdown with flow-cytometry cell-cycle analysis and Western blot in multiple myeloma

   PMID:23142581

   Open questions at the time

   • Whether p21 regulation is direct not established in this study
   • Single cell-type context
4. 2014 Medium

   Resolved how ANKHD1 controls p21 — by direct promoter binding and transcriptional repression, with nucleocytoplasmic shuttling enabling nuclear function.

   Evidence Co-IP, ChIP, luciferase reporter, and Leptomycin B imaging

   PMID:25483783

   Open questions at the time

   • DNA-binding domain mediating promoter occupancy not mapped
   • Cofactors at the p21 promoter unknown
5. 2014 Medium

   Connected ANKHD1 to the Hippo effector YAP1 and to the SIVA/Stathmin 1 axis, linking it to proliferation and migration control.

   Evidence Yeast two-hybrid, Co-IP, shRNA knockdown with xenograft and migration/proliferation assays

   PMID:24726915 PMID:25523139

   Open questions at the time

   • Whether ANKHD1 regulates YAP1 directly or via upstream kinases unresolved
   • Structural basis of SIVA interaction unknown
6. 2018 Medium

   Defined a direct RNA-binding mechanism: the KH domain binds and suppresses tumor-suppressor miRNAs to derepress Cyclin D1, and placed ANKHD1 upstream of YAP1/AKT-driven EMT.

   Evidence RNA immunoprecipitation, siRNA knockdown with cell-cycle analysis; YAP1 overexpression rescue in colorectal cancer

   PMID:29695508 PMID:30555746

   Open questions at the time

   • miRNA-binding specificity determinants in the KH domain not mapped
   • Direct vs indirect control of AKT phosphorylation unclear
7. 2019 High

   Revealed a chromatin function — partnering with SMYD3 to activate SLUG via active histone marks — and a structurally distinct membrane-deforming activity of the ankyrin repeat domain.

   Evidence MS, ChIP, EMSA, luciferase for SMYD3/SLUG; in vitro membrane deformation, dimerization, and domain mapping with endosome-size readout

   PMID:30646949 PMID:31255983

   Open questions at the time

   • How the same protein partitions between chromatin and membrane roles unknown
   • Physiological trigger for endosomal regulation undefined
8. 2020 Medium

   Extended the SMYD3 partnership to CDK2 transcriptional control and chemoresistance, and identified an ANKHD1/MALAT1/YAP1 feedback loop governing radioresistance.

   Evidence Co-IP, immunofluorescence, ChIP in NSCLC; RIP and RNA pulldown with knockdown and xenografts in CRC

   PMID:33773404 PMID:35110552

   Open questions at the time

   • Stoichiometry and assembly order of ANKHD1/SMYD3 and ANKHD1/MALAT1 complexes unknown
   • Direct lncRNA-binding region not mapped
9. 2020 Low

   Implicated ANKHD1 in S-phase histone synthesis and DNA repair through histone-promoter occupancy and γH2AX accumulation upon loss.

   Evidence ChIP, Western blot, flow cytometry (γH2AX), siRNA knockdown (authors note preliminary)

   PMID:32562952

   Open questions at the time

   • Findings noted as preliminary by the authors
   • Direct vs indirect effect on histone gene transcription unresolved
10. 2025 Medium

    Provided in vivo genetic evidence that ANKHD1 drives proliferation via direct CDK4 binding and Rb phosphorylation, and demonstrated a disease role in ADPKD cystic growth.

    Evidence Co-IP, conditional knockout mouse models, pRb Western blot, in vitro/in vivo cyst growth

    PMID:40457431

    Open questions at the time

    • Mechanism of p19-dependence not detailed
    • Whether CDK4 binding is direct or scaffold-mediated unresolved
11. 2025 Low

    Reported a protective gain-of-function for ANKHD1 in tauopathy, reducing phospho-Tau and restoring cognition, broadening its biology beyond cancer.

    Evidence Cre-inducible ANKHD1 transgenic PS19 mouse, phospho-Tau immunostaining, behavioral assay, autophagy markers

    PMID:40806649

    Open questions at the time

    • Autophagy mechanism inferred, not directly demonstrated
    • Sex-specific effect unexplained
12. 2026 Medium

    Linked carcinogen exposure to ANKHD1 induction via p300/H3K27ac and defined a splicing function through RBM39 to regulate MKI67, tying upstream epigenetic control to a downstream proliferative output.

    Evidence CUT&RUN-seq, mRNA-seq, Co-IP (ANKHD1-RBM39), pre-mRNA splicing assay, knockdown rescue in CRC

    PMID:42061695

    Open questions at the time

    • Direct RBM39-ANKHD1 binding interface not mapped
    • Breadth of ANKHD1-regulated splicing events beyond MKI67 unknown

• How ANKHD1's distinct domains coordinate its membrane-deforming, RNA/miRNA-binding, chromatin, and splicing activities within a single regulatory program remains unresolved.
• No integrated structural model of full-length ANKHD1
• Unclear which activities are context-specific vs constitutive
• Determinants of subcellular partitioning between membrane, cytoplasm, and nucleus undefined