Affinage

STK32A

Serine/threonine-protein kinase 32A · UniProt Q8WU08

Round 2 corrected
Length
396 aa
Mass
46.4 kDa
Annotated
2026-04-28
31 papers in source corpus 11 papers cited in narrative 11 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

STK32A is an N-myristoylated AGC-family serine/threonine kinase that functions in planar cell polarity, sleep regulation, and cancer signaling. In the inner ear, STK32A is transcriptionally repressed by EMX2 and acts to align stereociliary bundle orientation with core planar cell polarity (PCP) proteins by controlling apical localization of the transmembrane receptor GPR156; genetic epistasis places STK32A as a negative regulator of GPR156-mediated polarity reversal in both vestibular and cochlear hair cells (PMID:37144879, PMID:41208475). In the nervous system, STK32A promotes wakefulness downstream of neurotensin and serotonergic raphe signaling, and its loss in zebrafish and mice increases sleep and impairs sleep homeostasis, in part through reduced phosphorylation of neurofilament proteins in sensory and motor neurons (PMID:41406966). In non-small cell lung cancer cells, RUNX2-driven STK32A expression activates NF-κB p65 phosphorylation to promote proliferation, migration, and epithelial–mesenchymal transition (PMID:32571328).

Mechanistic history

Synthesis pass · year-by-year structured walk · 6 steps
  1. 2002 Medium

    STK32A was first catalogued as an AGC-family serine/threonine kinase (YANK1) within the human kinome, establishing its classification but leaving substrates and biological roles entirely unknown.

    Evidence Genome-wide kinase identification via cDNA/EST mining and phylogenetic classification

    PMID:12471243

    Open questions at the time
    • No biochemical kinase activity demonstrated
    • No substrates or biological functions identified
    • Expression pattern not characterized
  2. 2015 High

    Demonstration that STK32A is co-translationally N-myristoylated established a lipid modification that could target the kinase to membranes, providing the first biochemical feature beyond its kinase domain classification.

    Evidence Metabolic labeling with radiolabeled myristic acid in cell-free and human cell systems, corroborated by bioorthogonal analogue tagging

    PMID:25043870 PMID:26308446

    Open questions at the time
    • Whether myristoylation is required for membrane localization or kinase activity in vivo was not tested
    • No endogenous substrates identified
  3. 2020 Medium

    Functional studies in NSCLC cells revealed that RUNX2-driven STK32A expression activates NF-κB p65 phosphorylation, linking STK32A kinase activity to proliferation, migration, and EMT — the first assignment of a signaling output to this kinase.

    Evidence Dual-luciferase reporter, Western blot for p65 phosphorylation, Transwell assays, xenograft tumor models

    PMID:32571328

    Open questions at the time
    • Whether STK32A directly phosphorylates p65 or acts through an intermediate kinase is unknown
    • Findings from a single lab in one cancer type
    • No structural or enzymological characterization of STK32A catalytic activity
  4. 2023 High

    Mouse knockout and ectopic-expression experiments revealed that STK32A is essential for aligning stereociliary bundle polarity with PCP proteins in inner ear hair cells, operating by controlling apical GPR156 localization — the first defined developmental role for this kinase.

    Evidence Stk32a knockout and gain-of-function in mouse vestibular maculae; immunofluorescence of GPR156 and PCP proteins; confocal imaging of bundle orientation

    PMID:37144879

    Open questions at the time
    • Direct phosphorylation substrate linking STK32A to GPR156 trafficking not identified
    • Mechanism by which STK32A suppresses GPR156 apical localization unresolved
  5. 2025 High

    Compound-mutant epistasis in mice ordered STK32A within a hierarchy: EMX2 represses Stk32a transcription, and STK32A in turn blocks GPR156-mediated polarity reversal, a relationship conserved in both utricle and cochlea.

    Evidence Double-mutant genetic epistasis (Gpr156;Stk32a and Emx2;Stk32a) with confocal imaging in vestibular and cochlear hair cells

    PMID:41208475

    Open questions at the time
    • Biochemical mechanism by which STK32A antagonizes GPR156 still undefined
    • Whether STK32A kinase activity is catalytically required (vs. scaffolding) not tested
  6. 2025 Medium

    A zebrafish forward genetic screen and mouse validation established STK32A as a conserved wakefulness-promoting gene acting downstream of neurotensin and serotonergic raphe signaling, with loss of function causing increased sleep and impaired sleep homeostasis.

    Evidence Zebrafish stk32a mutant behavioral analysis, optogenetic stimulation, genetic epistasis with raphe ablation, cross-species validation in Stk32a-mutant mice

    PMID:41406966

    Open questions at the time
    • Precise neuronal cell types and circuit mechanisms mediating STK32A's wakefulness-promoting role incompletely mapped
    • Neurofilament phosphorylation identified as a downstream readout but the direct STK32A substrate(s) in neurons remain unknown
    • Sleep study in mice not yet replicated independently

Open questions

Synthesis pass · forward-looking unresolved questions
  • No direct phosphorylation substrate of STK32A has been biochemically identified in any context; the catalytic mechanism, structural basis of substrate recognition, and whether kinase activity (versus scaffolding) is required for its developmental and neuronal functions remain open questions.
  • No in vitro kinase assay with defined substrate published
  • No crystal or cryo-EM structure available
  • Relationship between N-myristoylation and in vivo function untested

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0140096 catalytic activity, acting on a protein 2
Localization
GO:0005886 plasma membrane 2
Pathway
R-HSA-1266738 Developmental Biology 2 R-HSA-162582 Signal Transduction 1
Partners
EMX2GPR156RELARUNX2

Evidence

Reading pass · 11 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2002 STK32A (also called YANK1) was identified as a member of the AGC kinase superfamily in the comprehensive catalogue of the human kinome, classifying it as a serine/threonine protein kinase. Genomic sequence analysis, cDNA/EST database mining, and phylogenetic classification Science Medium 12471243
2015 STK32A protein is N-myristoylated at its N-terminus, as demonstrated by metabolic labeling experiments in both an insect cell-free protein synthesis system and in transfected human cells using radiolabeled myristic acid. Cell-free protein synthesis metabolic labeling with [3H]-myristic acid; metabolic labeling in transfected human cells; N-terminal peptide fusion reporter assays PloS one High 26308446
2014 STK32A was identified as a candidate N-myristoylated protein using a cell-free bioorthogonal myristic acid analogue labeling approach, supporting its N-myristoylation. Cell-free protein synthesis with azide-analogue of myristic acid followed by Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) biotin tagging and Western blot detection Analytical biochemistry Medium 25043870
2017 STK32A was identified as part of the human protein-protein interaction network (BioPlex 2.0) via affinity purification-mass spectrometry, placing it within cellular protein communities. Affinity purification-mass spectrometry (AP-MS) at proteome scale Nature Low 28514442
2020 STK32A was identified as part of the human binary protein interactome (HuRI), providing candidate interaction partners via yeast two-hybrid screening. Systematic yeast two-hybrid (Y2H) binary interaction screening across the human ORFeome Nature Low 32296183
2020 STK32A was identified as part of a kinase interaction network by AP-MS, expanding the known functional associations for this understudied kinase. Mass-spectrometry-based affinity purification covering >300 human kinases Molecular cell Low 32707033
2020 STK32A promotes NSCLC cell proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) by activating NF-κB p65 phosphorylation. The transcription factor RUNX2 binds to and upregulates STK32A expression, and miR-130a-5p suppresses this pathway by directly targeting RUNX2, thereby indirectly reducing STK32A levels and inhibiting tumor growth in vivo. Dual-luciferase reporter assay (miR-130a-5p→RUNX2 interaction); RT-qPCR and Western blot (STK32A and NF-κB p65 phosphorylation); cell viability (CCK-8), colony formation, Transwell migration/invasion assays; in vivo xenograft tumor model with RUNX2 overexpression BMC cancer Medium 32571328
2023 STK32A functions as a downstream effector negatively regulated by the transcription factor EMX2 in mouse inner ear hair cells. STK32A is expressed in EMX2-negative hair cells on one side of the line of polarity reversal (LPR). STK32A is necessary to align the intrinsic stereociliary bundle polarity with core planar cell polarity (PCP) proteins in EMX2-negative regions and is sufficient to reorient bundles when ectopically expressed in EMX2-positive regions. STK32A regulates planar polarity by controlling the apical localization of the transmembrane receptor GPR156. Mouse genetic loss-of-function (Stk32a knockout), ectopic gain-of-function expression, immunofluorescence localization of GPR156 and PCP proteins, confocal imaging of stereociliary bundle orientation in vestibular maculae eLife High 37144879
2025 Genetic epistasis experiments in mice with combined Gpr156/Stk32a or Emx2/Stk32a mutations established that: (1) GPR156 reverses stereociliary bundle orientation relative to the PCP axis but is blocked by STK32A activity; (2) EMX2 establishes the LPR boundary by repressing Stk32a transcription; and (3) these functional relationships are conserved in the cochlea despite the absence of polarity reversal there. Double-mutant mouse genetic epistasis (Gpr156;Stk32a and Emx2;Stk32a compound mutants), immunofluorescence, confocal imaging of hair cell bundle orientation in utricle and cochlea Journal of cell science High 41208475
2025 STK32A (stk32a) mutant zebrafish display increased sleep and impaired sleep homeostasis. In zebrafish, stk32a acts downstream of neurotensin signaling and the serotonergic raphe to promote wakefulness. Pth4 neuron-induced sleep is suppressed in stk32a mutants, possibly through stk32a-expressing neurons in the prethalamus that express parathyroid hormone receptors, placing stk32a in a hypothalamic-brainstem sleep circuit. Zebrafish genetic screen (stk32a loss-of-function mutants), optogenetic stimulation of Pth4 neurons, genetic epistasis with noradrenergic LC and serotonergic raphe neuron ablation, sleep/wake behavioral quantification Current biology : CB Medium 41406966
2025 stk32a mutation in zebrafish and mice causes increased sleep and impaired sleep homeostasis. stk32a acts downstream of neurotensin signaling and the serotonergic raphe. stk32a mutation reduces phosphorylation of neurofilament proteins in neurons that regulate motor activity and in lateral line hair cells that detect environmental stimuli; ablation of these stk32a-expressing cells phenocopies the sleep phenotype. Neurotensin signaling inhibits specific sensory and motor populations and blocks stimulus-evoked responses of neurons relaying hair cell sensory information, establishing stk32a as a conserved sleep regulator linking neuropeptidergic/neuromodulatory systems to homeostatic sleep drive through suppression of sensory and motor systems. Forward genetic screen in zebrafish informed by human GWAS; stk32a mutant behavioral analysis in zebrafish and mice; cell-type-specific ablation; phosphoproteomics (neurofilament phosphorylation); calcium imaging of sensory neuron responses; genetic epistasis with neurotensin and serotonergic raphe pathways bioRxivpreprint Medium bio_10.1101_2025.09.09.675098

Source papers

Stage 0 corpus · 31 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2002 The protein kinase complement of the human genome. Science (New York, N.Y.) 6292 12471243
2002 Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences. Proceedings of the National Academy of Sciences of the United States of America 1479 12477932
2017 Architecture of the human interactome defines protein communities and disease networks. Nature 1085 28514442
2020 A reference map of the human binary protein interactome. Nature 849 32296183
2003 Complete sequencing and characterization of 21,243 full-length human cDNAs. Nature genetics 754 14702039
2011 Phylogenetic-based propagation of functional annotations within the Gene Ontology consortium. Briefings in bioinformatics 656 21873635
2004 The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC). Genome research 438 15489334
2005 Diversification of transcriptional modulation: large-scale identification and characterization of putative alternative promoters of human genes. Genome research 409 16344560
2011 Image-based genome-wide siRNA screen identifies selective autophagy factors. Nature 405 22020285
2010 Personalized smoking cessation: interactions between nicotine dose, dependence and quit-success genotype score. Molecular medicine (Cambridge, Mass.) 108 20379614
2020 Kinase Interaction Network Expands Functional and Disease Roles of Human Kinases. Molecular cell 88 32707033
2004 The DNA sequence and comparative analysis of human chromosome 5. Nature 85 15372022
2013 A negative genetic interaction map in isogenic cancer cell lines reveals cancer cell vulnerabilities. Molecular systems biology 76 24104479
2016 Tobacco smoking and methylation of genes related to lung cancer development. Oncotarget 69 27323854
2021 Identification of Potential lncRNAs and miRNAs as Diagnostic Biomarkers for Papillary Thyroid Carcinoma Based on Machine Learning. International journal of endocrinology 26 34335744
2020 The microRNA-130a-5p/RUNX2/STK32A network modulates tumor invasive and metastatic potential in non-small cell lung cancer. BMC cancer 23 32571328
2016 Early Transcriptional Changes Induced by Wnt/β-Catenin Signaling in Hippocampal Neurons. Neural plasticity 21 28116168
2023 Sequential genome-wide CRISPR-Cas9 screens identify genes regulating cell-surface expression of tetraspanins. Cell reports 20 36724073
2015 Identification of Human N-Myristoylated Proteins from Human Complementary DNA Resources by Cell-Free and Cellular Metabolic Labeling Analyses. PloS one 17 26308446
2014 Cell-free identification of novel N-myristoylated proteins from complementary DNA resources using bioorthogonal myristic acid analogues. Analytical biochemistry 14 25043870
2023 The dark kinase STK32A regulates hair cell planar polarity opposite of EMX2 in the developing mouse inner ear. eLife 11 37144879
2021 Basic pH reversed-phase liquid chromatography (bRPLC) in combination with tip-based strong cation exchange (SCX-Tip), ReST, an efficient approach for large-scale cross-linked peptide analysis. Analytica chimica acta 11 34535262
2018 Identification of molecular pathways and candidate genes associated with cocks' comb size trait by genome-wide transcriptome analysis. Scientific reports 11 29386544
2009 Fine mapping of the CELIAC2 locus on chromosome 5q31-q33 in the Finnish and Hungarian populations. Tissue antigens 7 19845895
2023 Risk factors analysis and survival prediction model establishment of patients with lung adenocarcinoma based on different pyroptosis-related gene subtypes. European journal of medical research 4 38111060
2024 Acting mechanism and clinical significance of hsa_circ_0005927 in the invasion and metastasis of gastric cancer. Journal of Cancer 3 38947400
2025 Pth4 neurons define a novel hypothalamic circuit that promotes sleep via brainstem monoaminergic neurons. bioRxiv : the preprint server for biology 0 40964331
2025 Planar polarized organization of mouse hair cells is established and maintained by STK32A, GPR156 and EMX2. Journal of cell science 0 41208475
2025 Serine/threonine kinase 32 family proteins: The potential multifaceted regulators in cancer. Translational oncology 0 41275706
2025 Pth4 neurons define a novel hypothalamic circuit that promotes sleep via brainstem monoaminergic neurons. Current biology : CB 0 41406966
2021 Discoveries of the specific expression of lncRNAs and mRNAs in hippocampus of rats after traumatic brain injury. Ibrain 0 37786908