Affinage

WEE2

Wee1-like protein kinase 2 · UniProt P0C1S8

Length
567 aa
Mass
62.9 kDa
Annotated
2026-06-11
36 papers in source corpus 13 papers cited in narrative 13 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 6/6 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

WEE2 (WEE1B) is an oocyte-specific protein kinase that controls meiotic cell-cycle progression by catalyzing inhibitory phosphorylation of CDK1 (Cdc2) on tyrosine-15, thereby inactivating MPF and gating both meiotic arrest and meiotic exit (PMID:11029659, PMID:16169490). Biochemically it is a bona fide CDK1-Y15 kinase: recombinant WEE2 phosphorylates CDK1-Y15 in vitro and rescues the lethal phenotype of fission yeast wee1/mik1 mutants while inducing G2/M arrest when overexpressed (PMID:11029659). In the oocyte, WEE2 acts downstream of PKA to maintain prophase I (germinal vesicle) arrest; PKA phosphorylates WEE2 at an activating serine residue (Ser15 in mouse, Ser77 in pig) that enhances its CDK1-inhibitory activity, and knockdown triggers premature meiotic resumption (PMID:16169490, PMID:21123961). This arrest function requires nuclear localization: WEE2 is nuclear in arrested oocytes and is exported to the cytoplasm before germinal vesicle breakdown, and mislocalization or NLS deletion abolishes arrest (PMID:20083600, PMID:21123961). WEE2 is later reactivated at egg activation, where Ca2+-driven CaMKII signaling stimulates WEE2 to re-impose CDK1-Y15 phosphorylation and drive exit from metaphase II and pronucleus formation, cooperating with cyclin B proteolysis (PMID:21454751). In humans, biallelic loss-of-function mutations in WEE2 abolish oocyte CDK1-Y15 phosphorylation and cause total fertilization failure, a defect rescued by injection of wild-type WEE2 cRNA (PMID:29606300).

Mechanistic history

Synthesis pass · year-by-year structured walk · 11 steps
  1. 2000 High

    Established WEE2 as a catalytically active CDK1-inhibitory kinase, defining its core biochemical activity before its physiological context was known.

    Evidence In vitro kinase assay with recombinant protein, fission yeast rescue complementation, and GFP-fusion localization in HeLa cells

    PMID:11029659

    Open questions at the time
    • Did not establish the tissue or cell-cycle context of WEE2 function
    • Used heterologous systems rather than oocytes
  2. 2005 High

    Identified WEE2 as an oocyte-specific kinase maintaining prophase I arrest downstream of PKA, linking cAMP/PKA signaling to MPF suppression via an activating Ser15 phosphorylation.

    Evidence Oocyte cDNA expression screen, Xenopus overexpression, in vitro PKA phosphorylation, and RNAi in vitro and in transgenic mice

    PMID:16169490

    Open questions at the time
    • Did not resolve subcellular site of action
    • Direct PKA substrate status inferred from in vitro phosphorylation
  3. 2006 Medium

    Consolidated the model that PKA-mediated phosphorylation activates WEE2 to keep CDK1 tyrosine-15-phosphorylated and sustain arrest.

    Evidence Review synthesizing prior in vitro phosphorylation and RNAi data

    PMID:16418576

    Open questions at the time
    • No new primary data
    • Direct demonstration of in vivo PKA-WEE2 phosphorylation not provided
  4. 2010 High

    Showed that nuclear localization is required for WEE2 arrest function and that PKA-regulated nuclear export coordinates WEE2 with CDC25B relocalization at meiotic resumption.

    Evidence Reciprocal RNAi of WEE1B and MYT1, live imaging of GFP-fusions, and mislocalization rescue experiments in mouse oocytes

    PMID:20083600

    Open questions at the time
    • Molecular machinery driving WEE2 nuclear export not identified
    • Quantitative contribution of WEE2 vs MYT1 not separated
  5. 2010 High

    Demonstrated WEE2 oocyte specificity and downstream-of-cAMP placement in a primate model, and defined the activating PKA site and NLS dependence in pig.

    Evidence RT-PCR expression profiling, WEE2-GFP imaging, dsRNA knockdown under PDE3 inhibition in macaque oocytes, and PKA-site/NLS mutagenesis in porcine oocytes

    PMID:20200212 PMID:21123961

    Open questions at the time
    • Species divergence of the activating PKA site (Ser15 vs Ser77) mechanistically unexplained
    • Human PKA site not directly mapped
  6. 2011 High

    Revealed a second role for WEE2 at metaphase II exit, placing it downstream of Ca2+/CaMKII to re-inhibit CDK1 and enable pronucleus formation during egg activation.

    Evidence RNAi knockdown plus Ca2+ and CaMKII inhibitor manipulations with pronucleus formation readout establishing CaMKII to WEE1B to CDK1 epistasis in mouse oocytes

    PMID:21454751

    Open questions at the time
    • How CaMKII activates WEE2 biochemically not defined
    • Interplay with cyclin B proteolysis timing not fully resolved
  7. 2013 Medium

    Extended the PKA-WEE2(Ser15)-CDK1(Tyr15) axis to G2/M control in early one-cell embryos via cell-cycle-dependent Ser15 phosphorylation.

    Evidence Phospho-specific analysis and overexpression of a Ser15D phosphomimetic with CDK1-Tyr15 readout in mouse embryos

    PMID:23616086

    Open questions at the time
    • Based on overexpression rather than endogenous perturbation
    • Kinase responsible for Ser15 dephosphorylation in G2/M not identified
  8. 2018 High

    Established WEE2 as essential for human fertilization, causally linking loss-of-function mutations to total fertilization failure through abolished CDK1-Y15 phosphorylation.

    Evidence Exome/Sanger sequencing, patient oocyte immunofluorescence, in vitro phosphorylation, and cRNA rescue with blastocyst formation

    PMID:29606300

    Open questions at the time
    • Mechanism by which mutations cause abnormal serine phosphorylation not fully dissected
    • Genotype-phenotype spectrum across patients limited
  9. 2019 Medium

    Expanded the human mutational spectrum and confirmed disruption of the WEE2-CDK1 phosphorylation axis as the unifying defect in fertilization failure.

    Evidence Exome/Sanger sequencing, single-cell RT-PCR of a splice variant, pCDC2 immunofluorescence in patient oocytes, and molecular modeling

    PMID:30827523

    Open questions at the time
    • Effect of individual missense substitutions on catalysis not quantified
    • Partial vs complete loss not always distinguished
  10. 2020 Medium

    Provided structural insight into the WEE2 kinase domain and identified selective WEE2 inhibitors, distinguishing WEE2 pharmacologically from WEE1.

    Evidence Co-crystallization of the WEE2 kinase domain, HTS of ~26,000 compounds, ELISA CDK1 phosphorylation assay, and bovine IVF assay

    PMID:32667031

    Open questions at the time
    • Structure not independently replicated
    • Full-length WEE2 architecture and regulatory regions not resolved
  11. 2025 Low

    Additional patient-derived variants reinforced that catalytic activity toward CDK1-Y15 is the functionally critical output of WEE2.

    Evidence In vitro enzymatic and kinase activity assays of mutant WEE2 with pronucleus formation readouts and structural modeling

    PMID:40399709 PMID:40830301

    Open questions at the time
    • Single-lab functional assays without independent replication
    • Modest effect sizes complicate genotype-phenotype interpretation

Open questions

Synthesis pass · forward-looking unresolved questions
  • How PKA and CaMKII produce opposite cell-cycle outcomes through the same activating phosphorylation of WEE2, and the structural basis of full-length WEE2 regulation, remain unresolved.
  • No structure of full-length regulated WEE2
  • Biochemical mechanism coupling CaMKII to WEE2 activation undefined
  • Direct in vivo PKA-WEE2 phosphorylation in human oocytes not demonstrated

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0140096 catalytic activity, acting on a protein 4 GO:0016740 transferase activity 2 GO:0140110 transcription regulator activity 2
Localization
GO:0005634 nucleus 4 GO:0005829 cytosol 1
Pathway
R-HSA-1474165 Reproduction 3 R-HSA-1640170 Cell Cycle 3 R-HSA-162582 Signal Transduction 2
Partners
CAMK2CDC25BCDK1MYT1PKA

Evidence

Reading pass · 13 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2000 Human WEE2 (WEE1B) encodes a 561-amino-acid kinase that phosphorylates CDK1 (Cdc2) on tyrosine-15 in vitro, inactivating CDK1 kinase activity; recombinant WEE2 rescued the lethal phenotype of fission yeast wee1-50Δmik1 mutant and caused cell elongation due to G2/M arrest when overexpressed, demonstrating its catalytic role as a CDK1-inhibitory kinase. In vitro kinase assay with recombinant protein; fission yeast rescue complementation; GFP-fusion localization in HeLa cells (predominantly nuclear) Genes to cells : devoted to molecular & cellular mechanisms High 11029659
2005 Mouse WEE1B (WEE2) is an oocyte-specific kinase that maintains meiotic (prophase I) arrest by inhibiting Cdc2/MPF; it functions downstream of PKA, and Ser15 is the major PKA phosphorylation site in vitro; phosphorylation at Ser15 enhances its inhibitory activity; RNAi-mediated knockdown in mouse oocytes (in vitro and transgenic in vivo) causes premature meiotic resumption. Small-pool expression screen of mouse oocyte cDNA library; Xenopus oocyte overexpression assay; in vitro PKA phosphorylation assay; RNAi injection; transgenic RNAi mouse model Current biology : CB High 16169490
2006 WEE2 is proposed (and supported by prior experimental data) to be a direct PKA substrate in oocytes; the scenario is that PKA phosphorylation activates WEE2 to maintain Cdc2 in an inactive, tyrosine-15-phosphorylated state, thereby sustaining meiotic arrest. Review synthesizing PKA phosphorylation in vitro and RNAi functional data from prior work (see PMID 16169490) Cell cycle (Georgetown, Tex.) Medium 16418576
2010 WEE1B and MYT1 cooperate to maintain meiotic arrest in mouse oocytes and function in distinct subcellular compartments: WEE1B is nuclear during arrest and is exported to the cytoplasm shortly before germinal vesicle breakdown (GVBD), while CDC25B moves from cytoplasm to nucleus; these translocations are regulated by PKA inactivation and MPF activation respectively; mislocalized WEE1B fails to maintain meiotic arrest, demonstrating that nuclear localization is required for its meiotic arrest function. RNAi knockdown (WEE1B and MYT1 individually and combined); live imaging of GFP-fusions for subcellular localization; functional rescue experiments in mouse oocytes The Journal of cell biology High 20083600
2010 WEE2 is expressed exclusively in oocytes of the rhesus macaque ovary and localizes specifically to the nucleus of germinal vesicle-stage oocytes (via WEE2-GFP fusion microinjection); dsRNA-mediated knockdown of WEE2 promotes meiotic resumption even in the presence of a PDE3 inhibitor (high cAMP condition), placing WEE2 downstream of cAMP; overexpression of WEE2 delays meiotic reentry in both mice and macaques. Tissue RT-PCR expression profiling; WEE2-GFP mRNA microinjection and live imaging; long dsRNA RNAi knockdown in macaque oocytes; WEE2 mRNA overexpression in mouse and macaque oocytes Biology of reproduction High 20200212
2011 WEE1B is required for exit from metaphase II (MII) in mouse oocytes: Ca2+ signals activate CaMKII, which activates WEE1B, leading to inhibitory phosphorylation of Cdc2 (CDK1-Y15) and enabling pronucleus formation; WEE1B knockdown prevents pronucleus formation in response to Ca2+ signals, and CaMKII-driven MII exit is blocked by WEE1B knockdown, demonstrating that CDK1 inactivation at MII exit requires both cyclin B proteolysis and WEE1B-mediated CDK1 phosphorylation. RNAi knockdown of WEE1B in mouse oocytes; Ca2+ signal manipulation; CaMKII inhibitor treatment; pronucleus formation assay as readout; epistasis between CaMKII and WEE1B Science (New York, N.Y.) High 21454751
2013 In one-cell stage mouse embryos, WEE1B Ser15 is phosphorylated during G1/S phases and dephosphorylated during G2/M; overexpression of a phosphomimetic Ser15D mutant delays mitotic reentry more potently than wild-type WEE1B, mediated by direct CDK1-Tyr15 phosphorylation; this identifies PKA–WEE1B(Ser15)–CDK1(Tyr15) as a regulatory axis controlling G2/M transition in early embryos. Phospho-specific analysis in mouse embryos; mRNA overexpression of WEE1B Ser15D phosphomimetic mutant; CDK1-Tyr15 phosphorylation assay Molecular medicine reports Medium 23616086
2010 In porcine oocytes, the PKA phosphorylation site activating WEE1B is Ser77 (not Ser15 as in mouse); mutation of Ser77 to alanine abolishes WEE1B meiotic arrest function; nuclear localization of porcine WEE1B is essential for its activity, as deletion of the NLS causes cytoplasmic redistribution and loss of meiotic arrest maintenance. PKA phosphorylation site mutagenesis (Ser→Ala substitutions) with mRNA injection into porcine oocytes; NLS deletion construct; immunohistochemistry for localization The Journal of reproduction and development Medium 21123961
2018 Homozygous loss-of-function mutations in WEE2 (missense or frameshift) cause total fertilization failure in humans; all four mutations significantly decreased WEE2 protein levels in affected individuals' oocytes, led to abnormal serine phosphorylation of WEE2 and reduced tyrosine-15 phosphorylation of Cdc2 in vitro; injection of WEE2 cRNA into affected oocytes rescued fertilization failure and enabled blastocyst formation, establishing WEE2 as essential for human fertilization through its CDK1-Y15 kinase activity. Human genetics (whole-exome + Sanger sequencing); immunofluorescence of patient oocytes; in vitro phosphorylation assay; cRNA rescue injection into patient oocytes; blastocyst formation assay American journal of human genetics High 29606300
2020 Co-crystallization of WEE2 kinase domain with WEE1 inhibitors revealed the structural basis of action across WEE kinases; type I inhibitors (including MK1775) were not selective for WEE2 over WEE1; high-throughput screening of ~26,000 compounds identified two selective WEE2 inhibitors (GPHR-00336382 binding full-length WEE2 allosterically; GPHR-00355672 binding the kinase domain); WEE2 phosphorylation of CDK1 was measured by ELISA, and inhibition of metaphase II exit was validated by bovine in vitro fertilization assay. Co-crystallization of WEE2 kinase domain; FTMap/FTSite and SiteMap in silico screening for allosteric sites; HTS of 26,000 compounds; ELISA-based CDK1 phosphorylation assay; bovine IVF assay; somatic cell proliferation assay (WEE1 selectivity) Biology of reproduction Medium 32667031
2019 Additional biallelic mutations in WEE2 (splice-site, missense, frameshift) cause fertilization failure or poor fertilization; a splice-site mutation c.1136-2A>G causes frameshift and premature stop; missense mutations produce changes in secondary protein structure; mutant WEE2 results in loss of phosphorylated CDC2 (CDK1-Y15) as detected by immunostaining in patient oocytes, confirming the kinase-CDK1 phosphorylation axis is disrupted. Whole-exome sequencing; Sanger sequencing; single-cell RT-PCR for splice-site mutation effect in vivo; immunofluorescence for pCDC2 in patient oocytes; molecular modeling Fertility and sterility Medium 30827523
2025 A novel WEE2 variant c.487T>A (p.Tyr163Asn) showed a 20.97% reduction in enzymatic activity in a functional assay, further confirming the kinase activity of WEE2 as essential for its biological function in fertilization. In vitro enzymatic activity assay of mutant WEE2 protein; Sanger sequencing; structural modeling Journal of assisted reproduction and genetics Low 40399709
2025 A novel WEE2 variant c.791C>T (p.Ala264Val) significantly decreased tyrosine-15 phosphorylation of Cdc2 and reduced pronucleus formation rate in vitro, confirming the functional requirement of this residue for WEE2 kinase activity toward CDK1. In vitro kinase activity assay measuring CDK1-Y15 phosphorylation; pronucleus formation assay; structural modeling Journal of assisted reproduction and genetics Low 40830301

Source papers

Stage 0 corpus · 36 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2005 Wee1B is an oocyte-specific kinase involved in the control of meiotic arrest in the mouse. Current biology : CB 170 16169490
2018 Homozygous Mutations in WEE2 Cause Fertilization Failure and Female Infertility. American journal of human genetics 152 29606300
2010 Wee1B, Myt1, and Cdc25 function in distinct compartments of the mouse oocyte to control meiotic resumption. The Journal of cell biology 125 20083600
2006 New pathways from PKA to the Cdc2/cyclin B complex in oocytes: Wee1B as a potential PKA substrate. Cell cycle (Georgetown, Tex.) 117 16418576
2011 Protein tyrosine kinase Wee1B is essential for metaphase II exit in mouse oocytes. Science (New York, N.Y.) 95 21454751
2000 Identification and characterization of human Wee1B, a new member of the Wee1 family of Cdk-inhibitory kinases. Genes to cells : devoted to molecular & cellular mechanisms 55 11029659
2010 WEE2 is an oocyte-specific meiosis inhibitor in rhesus macaque monkeys. Biology of reproduction 47 20200212
2022 CAF-derived exosomal WEE2-AS1 facilitates colorectal cancer progression via promoting degradation of MOB1A to inhibit the Hippo pathway. Cell death & disease 45 36123327
2020 LncRNA WEE2-AS1 promotes proliferation and inhibits apoptosis in triple negative breast cancer cells via regulating miR-32-5p/TOB1 axis. Biochemical and biophysical research communications 35 32307083
2019 Homozygous missense mutation Arg207Cys in the WEE2 gene causes female infertility and fertilization failure. Journal of assisted reproduction and genetics 35 30826994
2019 New biallelic mutations in WEE2: expanding the spectrum of mutations that cause fertilization failure or poor fertilization. Fertility and sterility 34 30827523
2018 Hepatitis B virus X protein related lncRNA WEE2-AS1 promotes hepatocellular carcinoma proliferation and invasion. Biochemical and biophysical research communications 34 30471857
2022 The N6-methyladenosine-mediated lncRNA WEE2-AS1 promotes glioblastoma progression by stabilizing RPN2. Theranostics 33 36168628
2019 Novel WEE2 gene variants identified in patients with fertilization failure and female infertility. Fertility and sterility 32 30827524
2019 Novel mutations in WEE2: Expanding the spectrum of mutations responsible for human fertilization failure. Clinical genetics 31 30628060
2019 Novel compound heterozygous mutations in WEE2 causes female infertility and fertilization failure. Journal of assisted reproduction and genetics 31 31428887
2020 Novel compound heterozygous mutation in WEE2 is associated with fertilization failure: case report of an infertile woman and literature review. BMC women's health 24 33148236
2020 Long Noncoding RNA WEE2-AS1 Plays an Oncogenic Role in Glioblastoma by Functioning as a Molecular Sponge for MicroRNA-520f-3p. Oncology research 19 32838835
2021 Novel WEE2 compound heterozygous mutations identified in patients with fertilization failure or poor fertilization. Journal of assisted reproduction and genetics 17 34476630
2021 Clinical exome sequencing identifies novel compound heterozygous mutations of the WEE2 gene in primary infertile women with fertilization failure. Gynecological endocrinology : the official journal of the International Society of Gynecological Endocrinology 12 33904356
2020 Development of WEE2 kinase inhibitors as novel non-hormonal female contraceptives that target meiosis†. Biology of reproduction 12 32667031
2013 Ser 15 of WEE1B is a potential PKA phosphorylation target in G2/M transition in one-cell stage mouse embryos. Molecular medicine reports 9 23616086
2019 Identification and Screening of Selective WEE2 Inhibitors to Develop Non-Hormonal Contraceptives that Specifically Target Meiosis. ChemistrySelect 7 32190728
2014 Wee1B depletion promotes nuclear maturation of canine oocytes. Theriogenology 7 25457679
2024 Novel splicing mutations in PATL2 and WEE2 cause oocyte degradation and fertilization failure. Journal of assisted reproduction and genetics 6 39476306
2020 Antisense long non‑coding RNA WEE2‑AS1 regulates human vascular endothelial cell viability via cell cycle G2/M transition in arteriosclerosis obliterans. Molecular medicine reports 6 33174040
2023 Novel WEE2 homozygous mutations c.1346C>T and c.949A>T identified in primary infertile women due to unexplained fertilization failure. Clinical genetics 5 37772619
2022 Total fertilization failure with in vitro fertilization-intracytoplasmic sperm injection related to WEE2 mutation highlights emerging importance of genetic causes of in vitro fertilization failure. F&S reports 5 36568932
2010 Analyses of the regulatory mechanism of porcine WEE1B: the phosphorylation sites of porcine WEE1B and mouse WEE1B are different. The Journal of reproduction and development 5 21123961
2022 LncRNA WEE2-AS1 knockdown inhibits the proliferation, migration and invasion of glioma cells via regulating miR-29b-2-5p/TPM3 axis. Oncology research 4 37305396
2022 LncRNA WEE2-AS1 Knockdown Inhibits the Proliferation, Migration and 3 Invasion of Glioma Cells via Regulating miR-29b-2-5p/TPM3 Axis. Oncology research 3 35393008
2025 Identification of novel variants and expansion of the phenotypic spectrum in PATL2, WEE2, and TUBB8 associated with human early embryonic arrest. Journal of assisted reproduction and genetics 2 40399709
2025 Novel homozygous variants in ASTL and WEE2 responsible for female infertility characterized by abnormal fertilization. Journal of assisted reproduction and genetics 1 40830301
2026 Identification of FDA-Approved Drugs as Potential Inhibitors of WEE2: Structure-Based Virtual Screening and Molecular Dynamics with Perspectives for Machine Learning-Assisted Prioritization. Life (Basel, Switzerland) 0 41752823
2025 Association of WEE2 Gene Polymorphism with Fertilization Failure in Women Undergoing Intracytoplasmic Sperm Injection. International journal of women's health 0 40979307
2024 [Analysis of a Chinese pedigree with female infertility due to WEE2 gene c.495del homozygous frameshifting variant induced fertilization disorder]. Zhonghua yi xue yi chuan xue za zhi = Zhonghua yixue yichuanxue zazhi = Chinese journal of medical genetics 0 39653355

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