ANKRD37

ANKRD37 is a hypoxia-responsive ankyrin-repeat protein that acts as a direct HIF-1 transcriptional target and contributes to the cellular response to low oxygen (PMID:19491311, PMID:32679233). Its protein product carries ankyrin repeats and a nuclear localization signal, and nuclear translocation of ANKRD37 is required for its activity: in colon cancer cells, HIF-1α-driven ANKRD37 promotes hypoxia-induced autophagy and cell growth (PMID:32679233). ANKRD37 binds Fem1b, facilitates Fem1b's cytoplasm-to-nucleus transport, and is itself targeted by Fem1b for ubiquitin-mediated degradation, placing it within a reciprocal regulatory partnership (PMID:21723927). Beyond hypoxia, ANKRD37 restrains trophoblast migration and invasion through the NF-κB pathway, acting on p65 and IκBα phosphorylation (PMID:35218282), and its overexpression in mouse hippocampus reduces hippocampal volume via a causal chain originating from a methylation QTL (PMID:36195640).

1. 2009 Medium

   Established ANKRD37 as a transcriptional output of hypoxia signaling, defining its primary regulatory context as a HIF-1 target gene.

   Evidence Integrative genomics combining microarray expression with HIF-1 binding-site scoring and experimental validation

   PMID:19491311

   Open questions at the time

   • Exact validation method (ChIP vs reporter) not detailed
   • No functional consequence of the induction tested in this study
   • Tissue/context specificity of HIF-1 regulation not defined
2. 2011 High

   Defined ANKRD37 at the protein level as an ankyrin-repeat, NLS-bearing protein and identified Fem1b as a direct partner that both is escorted to the nucleus by ANKRD37 and targets ANKRD37 for ubiquitin-mediated degradation.

   Evidence Yeast two-hybrid, reciprocal co-immunoprecipitation, co-transfection immunofluorescence, and ubiquitination assays during mouse spermatogenesis and in CHO cells

   PMID:21723927

   Open questions at the time

   • Functional outcome of the ANKRD37-Fem1b axis in spermatogenesis not established
   • Whether Fem1b degradation links to hypoxia signaling untested
   • E3 ligase identity / degradation pathway details not resolved
3. 2020 Medium

   Connected ANKRD37 induction to a concrete cellular phenotype, showing nuclear ANKRD37 is required for hypoxia-induced autophagy and cell growth.

   Evidence siRNA knockdown with immunoblot and immunofluorescence in hypoxic RKO colon cancer cells

   PMID:32679233

   Open questions at the time

   • Molecular mechanism linking nuclear ANKRD37 to autophagy machinery unknown
   • Direct nuclear targets or binding partners mediating the effect not identified
   • Single cell line / single lab
4. 2022 Medium

   Showed ANKRD37 suppresses trophoblast migration and invasion, placing NF-κB downstream of its activity.

   Evidence Knockdown and overexpression with wound-healing, Transwell, explant outgrowth assays, RNA-seq, and Western blot for p-p65/p-IκBα in HTR8/SVneo and JEG-3 cells

   PMID:35218282

   Open questions at the time

   • Direct mechanism by which ANKRD37 engages NF-κB signaling not defined
   • Relationship to hypoxia/HIF-1 axis in trophoblasts not tested
   • Single lab
5. 2022 High

   Established a causal genotype-to-phenotype chain whereby ANKRD37 overexpression reduces hippocampal volume.

   Evidence CRISPR genome/epigenome editing of rs1053218 and cg26741686, in vivo hippocampal overexpression, and cross-omics neuroimaging analysis

   PMID:36195640

   Open questions at the time

   • Molecular mechanism by which ANKRD37 affects hippocampal volume unknown
   • Whether HIF-1/Fem1b/NF-κB axes are involved in the neural phenotype untested

• The unifying molecular function of nuclear ANKRD37 — how its ankyrin repeats and Fem1b interaction mechanistically drive autophagy, NF-κB modulation, and tissue-specific phenotypes — remains undefined.
• No biochemical activity assigned to the ankyrin-repeat protein
• No structural model or defined nuclear effector targets
• Iron-status regulation (#5) not connected mechanistically to other functions