Affinage

WNK2

Serine/threonine-protein kinase WNK2 · UniProt Q9Y3S1

Length
2297 aa
Mass
242.7 kDa
Annotated
2026-06-11
24 papers in source corpus 13 papers cited in narrative 13 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 7/7 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

WNK2 is a serine/threonine protein kinase that acts as a tumor suppressor by restraining mitogenic ERK1/2 signaling and small-GTPase-driven motility (PMID:17667937, PMID:18593598, PMID:31349001). Its catalytic activity, which is autophosphorylating and enhanced by hypertonic stress, is required to suppress ERK1/2 activation: loss of WNK2 by RNAi or a kinase-dead K207M mutant increases MEK1 phosphorylation at Ser298 and potentiates EGF-induced G1/S progression (PMID:17667937, PMID:17578925). Mechanistically, WNK2 maintains RhoA activation and limits GTP-loading of Rac1; depletion shifts this balance toward active Rac1, engaging the Rac1 effector PAK1 to phosphorylate MEK1(S298) and drive ERK1/2 activity (PMID:18593598, PMID:23035050). Through control of Rac1, WNK2 also limits MMP2 activity and JNK signaling, thereby suppressing cell invasion and migration across glioma, breast, and lung cancer cells (PMID:23035050, PMID:25596741, PMID:33251331). WNK2 is silenced in cancers by promoter-level repression via CBX8 (PMID:33251331), and germline WNK2 variants that elevate phospho-PAK1/2, phospho-ERK1/2, CCND1, and MMP2 activity confirm its normal suppressive role in the MAPK pathway (PMID:36270769). Independent of its proliferative-control role, WNK2 is a neuron-enriched kinase that complexes with SPAK and phosphorylates it at Ser383, reciprocally activating NKCC1 and inhibiting KCC2 to promote intracellular chloride accumulation (PMID:21733846). WNK2 additionally acts downstream of PAX6 to drive corneal epithelial differentiation (PMID:39453672).

Mechanistic history

Synthesis pass · year-by-year structured walk · 13 steps
  1. 2007 High

    Established that WNK2 catalytic activity restrains the ERK-MAPK proliferative pathway, answering whether WNK2 is a positive or negative regulator of mitogenic signaling.

    Evidence RNAi depletion and kinase-dead K207M overexpression with pMEK1(S298)/pERK1/2 readout and cell cycle analysis in HeLa and HT29 cells

    PMID:17667937

    Open questions at the time
    • Did not resolve the intermediate GTPases linking WNK2 to MEK1(S298)
    • Direct kinase substrate of WNK2 in this pathway not identified
  2. 2007 Medium

    Demonstrated that WNK2 is an active autophosphorylating kinase stimulated by hypertonicity, but that its suppression of glioma colony formation can proceed kinase-independently, separating catalytic from non-catalytic functions.

    Evidence In vitro autophosphorylation kinase assay under hypertonic stress and colony formation with wild-type versus kinase-mutant WNK2

    PMID:17578925

    Open questions at the time
    • Mechanism of kinase-independent colony suppression undefined
    • Single lab, single study
  3. 2008 Medium

    Resolved the missing pathway link by showing WNK2 controls a RhoA-Rac1 cross-talk that gates PAK1-mediated MEK1(S298) phosphorylation.

    Evidence RNAi depletion with active RhoA/Rac1 GTPase pull-downs and pPAK1/pMEK1(S298)/pERK1/2 immunoblots in HeLa cells

    PMID:18593598

    Open questions at the time
    • How WNK2 biochemically maintains RhoA activity not established
    • Single lab
  4. 2011 High

    Identified a distinct neuronal function: WNK2 controls chloride homeostasis through SPAK, answering how WNK2 couples to ion cotransporters.

    Evidence 86Rb+ uptake in Xenopus oocytes, TiO2 phosphopeptide enrichment and mass spectrometry identifying SPAK Ser383 phosphorylation, kinase-dead analysis

    PMID:21733846

    Open questions at the time
    • Physiological consequences in intact neurons not tested
    • Relationship between neuronal SPAK axis and tumor-suppressive GTPase axis unexplored
  5. 2012 Medium

    Extended WNK2's role to invasion/migration by showing WNK2 re-expression in silenced glioblastoma suppresses Rac1 activation and motility in vitro and in vivo.

    Evidence WNK2 re-expression and siRNA knockdown with active Rac1 pull-down, invasion/migration assays, and xenografts

    PMID:23035050

    Open questions at the time
    • Direct molecular link between WNK2 and Rac1 GEFs/GAPs not defined
    • Single lab
  6. 2013 Low

    Generalized WNK2 ERK suppression to pancreatic cancer via overexpression growth assays and inverse correlation with pERK1/2 in tissue.

    Evidence WNK2 overexpression in PDAC cell lines with growth assays and pERK1/2 IHC in patient tissues

    PMID:23912455

    Open questions at the time
    • Correlative IHC without epistasis experiment
    • Single lab
  7. 2015 Medium

    Added a parallel invasion-suppressing branch by placing WNK2 upstream of JNK and MMP2.

    Evidence WNK2 knockdown/re-expression in glioma with JNK activity assay, MMP2 zymography, Western blot

    PMID:25596741

    Open questions at the time
    • Mechanism by which WNK2 inhibits JNK undefined
    • Single lab, single study
  8. 2019 Medium

    Confirmed WNK2 as a bona fide tumor suppressor in hepatocellular carcinoma acting through ERK1/2, with in vivo and genomic support.

    Evidence WNK2 loss-of-function in HCC cells, pERK1/2 immunoblot, xenografts, and patient somatic mutation/copy number analysis

    PMID:31349001

    Open questions at the time
    • Mechanism of tumor-associated macrophage recruitment not detailed
    • Single lab
  9. 2020 Low

    Identified an additional cellular output of WNK2 by showing overexpression inhibits autophagic flux independently of mTOR.

    Evidence WNK2 overexpression in A172 cells with LC3A/B and p62 markers under bafilomycin/everolimus treatment

    PMID:32093151

    Open questions at the time
    • mTOR independence inferred indirectly
    • Single overexpression experiment, single lab
  10. 2020 Medium

    Defined the upstream silencing mechanism, showing CBX8 represses WNK2 to derepress Rac1/MMP2-driven invasion across multiple cancer types.

    Evidence ChIP of CBX8 at WNK2 promoter, bidirectional WNK2 manipulation, Rac1 pull-down and MMP2 activity in glioblastoma, breast, and lung cells

    PMID:33251331

    Open questions at the time
    • Whether CBX8 repression operates in non-cancer contexts unknown
    • Single lab
  11. 2022 Medium

    Demonstrated that germline WNK2 variants impair its suppression of the PAK1/2-MAPK axis, linking genetic variation to dysregulated proliferation.

    Evidence CRISPR/Cas9 WNK2 disruption in HT-29 plus lentiviral variant overexpression with pPAK1/2, pERK1/2, CCND1 immunoblots and colony/MMP2 assays

    PMID:36270769

    Open questions at the time
    • Clinical phenotype associated with these variants not established
    • Single lab
  12. 2024 Medium

    Revealed a developmental role placing WNK2 downstream of PAX6 in corneal epithelial differentiation.

    Evidence PAX6 shRNA knockdown with RNA-seq, WNK2 knockdown in air-liquid LSC differentiation, marker qRT-PCR/immunofluorescence

    PMID:39453672

    Open questions at the time
    • Effector mechanism downstream of WNK2 in corneal cells not defined
    • Single lab
  13. 2025 Low

    Implicated WNK2 in hyperosmotic stress sensing in chondrocytes relevant to osteoarthritis.

    Evidence WNK2 variant overexpression and loss-of-function in human chondrocytes with transcriptomics under hyperosmotic stress and OA tissue IHC

    PMID:40592720

    Open questions at the time
    • No defined downstream effector assay
    • Mechanism of osmosensing transduction unresolved
    • Single lab

Open questions

Synthesis pass · forward-looking unresolved questions
  • How WNK2 biochemically maintains RhoA activation and selectively restrains Rac1 GTP-loading, and whether its neuronal SPAK/ion-cotransporter axis and its tumor-suppressive GTPase axis share a common catalytic mechanism, remain unresolved.
  • Direct GTPase regulators (GEF/GAP) targeted by WNK2 not identified
  • No structural model linking kinase activity to GTPase control
  • Integration of neuronal and oncogenic functions unexplored

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0140096 catalytic activity, acting on a protein 3 GO:0016740 transferase activity 2 GO:0098772 molecular function regulator activity 2
Pathway
R-HSA-162582 Signal Transduction 3 R-HSA-1643685 Disease 3 R-HSA-382551 Transport of small molecules 1
Partners
MEK1PAK1SPAK

Evidence

Reading pass · 13 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2011 WNK2 is a neuron-enriched kinase that reciprocally activates NKCC1 and inhibits KCC2 in a kinase-dependent manner, promoting chloride accumulation; WNK2 forms a protein complex in mammalian brain with SPAK, in which SPAK is phosphorylated at Ser-383 (a consensus WNK recognition site), as demonstrated by TiO2 enrichment, tandem mass spectrometry, and Xenopus oocyte uptake assays. 86Rb+ uptake assays in Xenopus oocytes, TiO2 phosphopeptide enrichment, tandem mass spectrometry, kinase-dead mutant analysis The Journal of biological chemistry High 21733846
2007 WNK2 depletion by RNAi activates ERK1/2 via MEK1 phosphorylation at serine 298, increasing MEK1 activity; expression of a kinase-dead WNK2-K207M mutant also activates ERK1/2, indicating that WNK2 catalytic activity is required for this suppression; WNK2 depletion increases G1/S progression and potentiates EGF-induced proliferation. RNA interference, kinase-dead mutant (K207M) overexpression, Western blot for pMEK1(S298) and pERK1/2, cell cycle analysis in HeLa and HT29 cells Oncogene High 17667937
2007 WNK2 exhibits autophosphorylation and serine/threonine protein kinase activity that is enhanced under hypertonic conditions; WNK2 inhibits colony formation of glioma cells in a kinase-independent manner. In vitro kinase assay (autophosphorylation), hypertonic stress exposure, colony formation assay with wild-type and kinase-mutant WNK2 Proceedings of the National Academy of Sciences of the United States of America Medium 17578925
2008 WNK2 controls a RhoA–Rac1 cross-talk mechanism: WNK2 depletion decreases RhoA activation and increases GTP-loaded Rac1, which stimulates the Rac1-effector PAK1; PAK1 then phosphorylates MEK1 at serine 298, increasing MEK1 affinity for ERK1/2 and thereby activating ERK1/2 upon growth factor stimulation. RNAi-mediated WNK2 depletion, GTPase pull-down (active RhoA/Rac1 assays), Western blot for pPAK1, pMEK1(S298), pERK1/2 in HeLa cells Cellular signalling Medium 18593598
2012 WNK2 controls GTP-loading of Rac1; re-expression of WNK2 in glioblastoma cells reduces Rac1 activation and decreases cell invasion and migration, while depletion of endogenous WNK2 increases Rac1 activation and invasion. WNK2 re-expression in methylation-silenced glioblastoma cells, WNK2 siRNA knockdown, active Rac1 pull-down assay, invasion/migration assays, in vivo xenograft Human molecular genetics Medium 23035050
2015 WNK2 silencing is associated with activation of JNK and upregulation of MMP2 expression and activity in glioma cells; WNK2 inhibits JNK, and this is mechanistically linked to decreased MMP2 levels. WNK2 knockdown/re-expression in glioma cell lines, JNK activity assay, MMP2 zymography, Western blot Oncotarget Medium 25596741
2013 WNK2 overexpression in pancreatic ductal adenocarcinoma cells reduces cell growth, and WNK2 expression in tissues correlates negatively with pERK1/2, indicating WNK2 suppresses ERK-MAPK-driven proliferation in pancreatic cancer. WNK2 overexpression in PDAC cell lines, cell growth assays, immunohistochemistry for pERK1/2 in patient tissues Oncogene Low 23912455
2019 WNK2 inactivation in hepatocellular carcinoma leads to ERK1/2 signaling activation and promotes tumor growth, metastasis, and tumor-associated macrophage infiltration; WNK2 acts as a tumor suppressor through the ERK1/2 pathway in HCC. WNK2 loss-of-function in HCC cell lines, pERK1/2 Western blot, in vivo xenograft, somatic mutation and copy number analysis in patient samples Journal of hepatology Medium 31349001
2020 WNK2 overexpression inhibits autophagic flux in glioblastoma cells through a mTOR-independent pathway, as evidenced by decreased LC3B and p62 protein levels and reduced LC3A/B ratio under bafilomycin A1 + everolimus treatment. WNK2 overexpression in A172 glioblastoma cells, Western blot and immunofluorescence for LC3A/B and p62, autophagy inducer/inhibitor pharmacological assays, mTOR pathway analysis Cells Low 32093151
2020 CBX8 interacts with the WNK2 promoter to suppress WNK2 expression; decreased WNK2 results in increased Rac1 GTP-loading and MMP2 activity, promoting cancer cell invasion and migration; WNK2 negatively regulates both Rac1 and MMP2. ChIP assay of CBX8 at WNK2 promoter, WNK2 knockdown/overexpression, Rac1 GTPase pull-down, MMP2 activity assay, invasion/migration assays in glioblastoma, breast, and lung cancer cells Molecular therapy oncolytics Medium 33251331
2022 Germline WNK2 variants (p.Pro702Leu, p.Ala1607Val, p.Val2053Ile) display elevated phospho-PAK1/2, phospho-ERK1/2, CCND1 levels and increased clonogenic capacity and MMP2 activity compared to wild-type WNK2, confirming that WNK2 normally suppresses the MAPK pathway via PAK1/2 regulation. CRISPR/Cas9 WNK2 gene disruption in HT-29 cells, lentiviral WNK2 variant overexpression, immunoblot for pPAK1/2 and pERK1/2, colony formation and MMP2 assays Journal of medical genetics Medium 36270769
2024 WNK2 is a downstream transcriptional target of PAX6 in corneal epithelial cells; WNK2 knockdown impairs expression of corneal differentiation markers (KRT12, ALDH3A1, CLU) and activates keratinization, inflammation, and cell proliferation programs, indicating WNK2 is required for corneal epithelial cell differentiation and homeostasis. PAX6 shRNA knockdown followed by RNA-seq, WNK2 knockdown in LSC differentiation (air-liquid culture), qRT-PCR and immunofluorescence for CEC markers Investigative ophthalmology & visual science Medium 39453672
2025 Elevated WNK2 expression combined with hyperosmotic stress promotes an OA-associated transcriptional response in chondrocytes; OA-associated WNK2 coding variants exacerbate this response, indicating WNK2 functions in sensing and transducing hyperosmotic signals in chondrocytes. WNK2 variant overexpression and loss-of-function in immortalized and primary human chondrocytes, transcriptomic analysis under hyperosmotic stress, immunohistochemistry on human and mouse OA tissue RMD open Low 40592720

Source papers

Stage 0 corpus · 24 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2011 WNK2 kinase is a novel regulator of essential neuronal cation-chloride cotransporters. The Journal of biological chemistry 76 21733846
2007 Protein kinase WNK2 inhibits cell proliferation by negatively modulating the activation of MEK1/ERK1/2. Oncogene 69 17667937
2019 Genomic sequencing identifies WNK2 as a driver in hepatocellular carcinoma and a risk factor for early recurrence. Journal of hepatology 59 31349001
2007 Epigenome scans and cancer genome sequencing converge on WNK2, a kinase-independent suppressor of cell growth. Proceedings of the National Academy of Sciences of the United States of America 59 17578925
2012 Loss of WNK2 expression by promoter gene methylation occurs in adult gliomas and triggers Rac1-mediated tumour cell invasiveness. Human molecular genetics 46 23035050
2008 Epigenetic silencing of the kinase tumor suppressor WNK2 is tumor-type and tumor-grade specific. Neuro-oncology 45 19001526
2013 Early epigenetic downregulation of WNK2 kinase during pancreatic ductal adenocarcinoma development. Oncogene 33 23912455
2019 Long non-coding RNA LINC00858 exerts a tumor-promoting role in colon cancer via HNF4α and WNK2 regulation. Cellular oncology (Dordrecht, Netherlands) 28 31884577
2008 WNK2 modulates MEK1 activity through the Rho GTPase pathway. Cellular signalling 25 18593598
2020 Upregulated CBX8 Promotes Cancer Metastasis via the WNK2/MMP2 Pathway. Molecular therapy oncolytics 24 33251331
2015 Silencing of the tumor suppressor gene WNK2 is associated with upregulation of MMP2 and JNK in gliomas. Oncotarget 24 25596741
2020 Long non-coding RNA LINC00858 inhibits colon cancer cell apoptosis, autophagy, and senescence by activating WNK2 promoter methylation. Experimental cell research 22 32768499
2019 microRNA-370 Promotes Cell Growth by Targeting WNK2 in Breast Cancer. DNA and cell biology 17 31009242
2021 Circ_0001666 affects miR-620/WNK2 axis to inhibit breast cancer progression. Genes & genomics 13 34061329
2020 LINC00858 knockdown inhibits gastric cancer cell growth and induces apoptosis through reducing WNK2 promoter methylation. Cellular oncology (Dordrecht, Netherlands) 9 32447640
2022 CircRNA-WNK2 Acts as a ceRNA for miR-328a-3p to Promote AANAT Expression in the Male Rat Pineal Gland. Endocrinology 7 34918065
2022 microRNA-324-3p suppresses the aggressive ovarian cancer by targeting WNK2/RAS pathway. Bioengineered 7 35549643
2024 PAX6-WNK2 Axis Governs Corneal Epithelial Homeostasis. Investigative ophthalmology & visual science 6 39453672
2020 WNK2 Inhibits Autophagic Flux in Human Glioblastoma Cell Line. Cells 6 32093151
2022 Germline mutations in WNK2 could be associated with serrated polyposis syndrome. Journal of medical genetics 4 36270769
2025 WNK2 variants associated with familial osteoarthritis alter the chondrocyte response to hyperosmotic stress. RMD open 1 40592720
2023 Regional bias of tumor suppressor gene mutations of STARD8 and WNK2 in colon cancers. Pathology, research and practice 1 38091885
2026 WNK2 may promote ovarian cancer progression by upregulating POU5F1B. PloS one 0 41628111
2024 Correction: Alves et al. WNK2 Inhibits Autophagic Flux in Human Glioblastoma Cell Line. Cells 2020, 9, 485. Cells 0 39056814

Missed literature

Know a paper Affinage missed for WNK2? Flag it for the maintainers and the community.

No submissions yet.