ANKRD6

ANKRD6 (Diversin) is a vertebrate planar cell polarity (PCP) protein that acts as a molecular switch suppressing canonical Wnt/β-catenin signaling while promoting non-canonical PCP signaling, thereby coordinating tissue morphogenesis during neural tube closure, inner ear hair-cell orientation, and wound repair. ANKRD6 localizes asymmetrically at cell junctions in sensory epithelia and neuroectoderm, where it functions upstream of Vangl2 polarization and is required for proper apical constriction and neural tube closure (PMID:25218921, PMID:40719643). It forms a mechanosensitive complex with ADIP that polarizes in response to cytoskeletal tension from neighboring cells, representing a PCP module distinct from classical core complexes (PMID:40562038). Rare hypomorphic missense mutations in ANKRD6 alter Wnt signaling balance and have been identified in patients with neural tube defects (PMID:25200652).

1. 2002 Medium

   Initial characterization revealed that Ankrd6 encodes an ankyrin-repeat protein with prominent expression in developing brain proliferative and migratory zones, establishing it as a candidate neurodevelopmental gene.

   Evidence In situ hybridization, Northern blot, and gene structure analysis in mouse embryos

   PMID:12203740

   Open questions at the time

   • No functional loss-of-function data
   • Brain-specific role not tested
   • Protein interaction partners unknown
2. 2005 Low

   Bioinformatic analyses placed ANKRD6 within the vertebrate PCP signaling network by predicting its domain-mediated interactions with Prickle, Vangl, Dishevelled, CKIε, and Axin, and proposed it as a switch from canonical to non-canonical Wnt signaling.

   Evidence Comparative genomics, domain analysis, and literature synthesis

   PMID:15647854 PMID:15809738

   Open questions at the time

   • Interactions were computationally predicted, not directly assayed by co-IP or pulldown
   • No functional validation of switch model
   • No in vivo loss-of-function
3. 2014 High

   Genetic loss-of-function in mouse demonstrated that ANKRD6 is a bona fide core PCP component: it localizes asymmetrically in inner ear sensory organs, its knockout causes PCP defects in hair-cell orientation, and it suppresses canonical Wnt signaling in embryonic fibroblasts.

   Evidence Mouse knockout, immunolocalization, Wnt reporter assays in MEFs, Drosophila cross-species rescue

   PMID:25218921

   Open questions at the time

   • Mechanism of asymmetric localization not defined
   • Direct binding partners not validated biochemically in this study
   • Neural tube phenotype not examined in mouse KO
4. 2014 Medium

   Identification of rare hypomorphic ANKRD6 missense mutations in neural tube defect patients, with functional validation showing altered Wnt signaling, linked ANKRD6 to human NTD susceptibility and confirmed its dual role as a canonical Wnt suppressor and PCP activator.

   Evidence Sequencing of NTD patient cohort, Wnt/β-catenin and PCP reporter assays with mutant constructs

   PMID:25200652

   Open questions at the time

   • Small patient cohort; population-level significance not established
   • No animal model rescue with patient mutations
   • Precise structural basis of hypomorphic activity unknown
5. 2019 Medium

   In a cancer context, ANKRD6 knockdown in melanoma cells increased proliferation and migration and reduced MAPK inhibitor sensitivity, demonstrating that its canonical Wnt-suppressive function is relevant beyond developmental PCP.

   Evidence siRNA knockdown, proliferation/migration assays, drug sensitivity assays in melanoma cell lines

   PMID:31338875

   Open questions at the time

   • Only siRNA knockdown, no stable KO or rescue
   • In vivo tumor relevance not tested
   • Interaction with melanoma-specific Wnt pathway components not characterized
6. 2025 High

   Discovery that Diversin forms a mechanosensitive complex with ADIP that is required for wound repair and polarizes in response to mechanical forces revealed a new PCP module linking cytoskeletal tension to polarity establishment.

   Evidence Co-immunoprecipitation, loss-of-function depletion, live imaging and wound healing in Xenopus embryos, mechanical force application

   PMID:40562038

   Open questions at the time

   • Structural basis of ADIP-Diversin interaction unknown
   • Whether this complex operates in mammalian tissues not tested
   • Force transduction mechanism from cytoskeleton to complex not defined
7. 2025 High

   Epistasis experiments established that Diversin acts upstream of Vangl2 polarization in the neuroectoderm and is required for apical constriction and neural tube closure, defining its position in the PCP hierarchy.

   Evidence Morpholino knockdown in Xenopus, immunofluorescence of endogenous Vangl2, live imaging

   PMID:40719643

   Open questions at the time

   • Whether Diversin directly recruits Vangl2 or acts indirectly unclear
   • Mouse neural tube phenotype from Ankrd6 KO not yet reported
   • Relationship between mechanosensitive ADIP complex and Vangl2 polarization not integrated
8. 2026 Medium

   Diversin was shown to be required for ADIP planar polarization in the neural plate, placing Diversin upstream of ADIP and solidifying the epistatic order within the mechanosensitive PCP module.

   Evidence Morpholino knockdown of Diversin, immunolocalization of endogenous ADIP in Xenopus neural plate

   PMID:41601266

   Open questions at the time

   • Single lab finding; independent replication needed
   • Whether Diversin physically recruits ADIP to the membrane or acts indirectly not resolved
   • Signaling inputs that activate Diversin itself remain unknown

• How Diversin integrates mechanical force sensing with PCP pathway activation, and the structural basis of its interactions with ADIP, Vangl2, and other PCP components, remain unresolved.
• No structural model of Diversin or its complexes
• Force transduction mechanism from cytoskeleton through ADIP-Diversin to Vangl2 polarization not defined
• Mammalian neural tube closure phenotype from Ankrd6 loss not characterized