The research report should be a detailed narrative explaining the function, biological processes, and localization of the gene product. Citations should be given for all claims.
You should prioritize authoritative reviews and primary scientific literature when conducting research. You can supplement
this with annotations you find in gene/protein databases, but these can be outdated or inaccurate.
We are specifically interested in the primary function of the gene - for enzymes, what reaction is catalyzed, and what is the substrate specificity? For transporters, what is the substrate? For structural proteins or adapters, what is the broader structural role? For signaling molecules, what is the role in the pathway.
We are interested in where in or outside the cell the gene product carries out its function.
We are also interested in the signaling or biochemical pathways in which the gene functions. We are less interested in broad pleiotropic effects, except where these elucidate the precise role.
Include evidence where possible. We are interested in both experimental evidence as well as inference from structure, evolution, or bioinformatic analysis. Precise studies should be prioritized over high-throughput, where available.
The target identity is verified. MAP3K1 is the approved human gene encoding mitogen-activated protein kinase kinase kinase 1, commonly called MEKK1; the literature describes the same approximately 196-kDa, 1,512-residue protein and the same C-terminal kinase plus N-terminal regulatory architecture as UniProt Q13233. No evidence was conflated with MAP3K2/MEKK2, MAP3K3/MEKK3, or nonhuman MEKK1 orthologues except where animal models are explicitly identified. (pham2013map3k1genomicalterations pages 1-3, bohlesUnknownyearautoregulationdynamicsof pages 24-28)
MAP3K1 is best regarded as a multifunctional intracellular stress- and cytoskeleton-responsive signaling enzyme with two catalytic activities. Its primary kinase function is ATP-dependent phosphorylation of MAP kinase kinases, with MAP2K4/MKK4 the best-supported preferred substrate, thereby driving the MKK4/MKK7–JNK–c-Jun cascade. Context-dependent coupling to MKK1/2–ERK also occurs. A RING/PHD-like domain additionally supplies E3 ubiquitin-ligase activity, enabling degradation-linked ubiquitylation of ERK1/2 and c-Jun and nondegradative Lys63-linked ubiquitylation of TAB1. Thus, MAP3K1 integrates phosphorylation, ubiquitin signaling, cytoskeletal state, and cell-fate decisions rather than acting as a simple linear MAP3K. (lu2002thephddomain pages 2-3, witowsky2003ubiquitylationofmekk1 pages 1-2, xia2007mekk1mediatesthe pages 1-2, charlaftis2014themekk1phd pages 1-2)
| Feature | Best-supported annotation | Principal evidence | Confidence / caveat |
|---|---|---|---|
| Identity and size | Human MAP3K1 encodes MEKK1 (UniProt Q13233), a signaling protein of 1,512 aa and approximately 196 kDa. | Literature equates MAP3K1 with MEKK1 and reports matching length, mass, and architecture (pham2013map3k1genomicalterations pages 1-3, bohlesUnknownyearautoregulationdynamicsof pages 24-28). | High. Identity matches the supplied UniProt record; it is not MAP3K2/MEKK2 or MAP3K3/MEKK3. |
| Domain architecture | N-terminal regulatory region containing SWIM, a six-HEAT-repeat TOG domain, a RING/PHD-like E3-ligase domain, and tandem ubiquitin-interacting motifs (UIMs); a caspase-3 site at Asp878 separates regulatory and catalytic regions; the C-terminal kinase domain spans 1243–1508. | Structural, biochemical, and sequence analyses; the isolated TOG domain binds curved tubulin (pham2013map3k1genomicalterations pages 1-3, bohlesUnknownyearautoregulationdynamicsof pages 24-28, bohlesUnknownyearautoregulationdynamicsof pages 28-31, filipcik2020acryptictubulinbindinga pages 1-2). | High for the overall architecture, TOG structure, Asp878, and kinase coordinates. “PHD” is the historical name for the RING-like E3 domain. |
| Protein-kinase reaction | ATP-dependent phosphorylation of MAP2Ks: ATP + MAP2K → ADP + phospho-MAP2K. Oligomerization supports trans-autophosphorylation and activation. | Biochemical assays and mechanistic reviews identify MAP2Ks as direct substrates and support oligomerization-dependent autophosphorylation (pham2013map3k1genomicalterations pages 1-3, bohlesUnknownyearautoregulationdynamicsofa pages 169-173, lu2002thephddomain pages 2-3). | High for protein Ser/Thr kinase activity; detailed catalytic constants and a strict peptide consensus are not established here. |
| Kinase substrate specificity | MKK4/MAP2K4 is the best-supported and preferred substrate, coupling MAP3K1 principally to JNK. MAP3K1 can also phosphorylate MKK1/MAP2K1 and signal through MKK7/MAP2K7; MKK1/2–ERK output is more context-dependent. | Strongest kinase activity toward MKK4; direct MKK1 and MKK4 phosphorylation; MKK4/MKK7 activation-loop phosphorylation supports JNK signaling (lu2002thephddomain pages 2-3, witowsky2003ubiquitylationofmekk1 pages 1-2, charlaftis2014themekk1phd pages 1-2). | High for MKK4; moderate for the physiological importance of MKK1/2 and MKK7 in each context. |
| E3 ubiquitin-ligase activity | The RING/PHD-like domain recruits ubiquitin-charged E2 enzymes and catalyzes substrate and self-ubiquitylation, integrating phosphorylation and ubiquitin signaling. | PHD/RING mutations impair ubiquitylation; kinase activity and intact full-length architecture can be required for efficient cellular ubiquitylation (lu2002thephddomain pages 3-5, witowsky2003ubiquitylationofmekk1 pages 2-3). | High. Chain topology and outcome depend on substrate, stimulus, and E2 enzyme. |
| ERK1/2 ubiquitylation | Under hyperosmotic stress, MAP3K1 associates with and polyubiquitylates ERK1/2, promoting proteasome-dependent degradation; endogenous proteins colocalize perinuclearly. | Purified-protein, NIH-3T3, and 293T experiments; MG132 blocked ERK loss, while PHD or kinase mutants impaired ubiquitylation (lu2002thephddomain pages 2-3, lu2002thephddomain pages 3-5). | High mechanistic confidence, although the effect is stress- and context-dependent. |
| c-Jun ubiquitylation | MAP3K1 promotes c-Jun ubiquitylation and proteasomal degradation during osmotic stress, limiting sustained c-Jun signaling and influencing apoptosis. | In-vitro and cellular assays; c-Jun loss occurred by 6 h after sorbitol exposure and was blocked by MAP3K1 deficiency (xia2007mekk1mediatesthe pages 1-2). | High in osmotic-stress models; other E3 ligases regulate c-Jun in other contexts. |
| TAB1 ubiquitylation | MAP3K1 catalyzes predominantly Lys63-linked, non-degradative polyubiquitylation of TAB1 through UBE2N–UBE2V1, promoting TAB1–TAK1 coupling and cytokine-induced JNK/p38 activation. | Protein-array discovery, biochemical assays, and an E3-defective Map3k1 knock-in model (charlaftis2014themekk1phd pages 1-2, charlaftis2014themekk1phd pages 2-3). | High mechanistic confidence, but much of the physiological evidence comes from mouse embryonic stem cells. |
| Localization | Dynamic intracellular localization in the perinuclear cytoplasm, at the plasma membrane, tight junctions, actin stress fibers, focal adhesions, and the leading edge of migrating cells; its TOG domain targets soluble curved tubulin and microtubule assembly/disassembly sites. | Imaging, interaction studies, and TOG-domain structural and biochemical analyses (filipcik2020acryptictubulinbindinga pages 1-2, lu2002thephddomain pages 2-3, lu2002thephddomain pages 3-5). | High that localization is stimulus- and partner-dependent; MAP3K1 is not a constitutive resident of one organelle. |
| Pathway outputs and cell-fate switch | Principal cascade: MAP3K1 → MKK4/MKK7 → JNK → c-Jun. Contextual outputs include ERK1/2, p38, TAK1, NF-κB, cytoskeletal remodeling, migration, survival, and apoptosis. Caspase cleavage at Asp878 releases a C-terminal kinase fragment associated with pro-apoptotic signaling. | Biochemical, genetic, and cell-biological evidence supports JNK predominance and distinct effects of full-length versus cleaved MAP3K1 (pham2013map3k1genomicalterations pages 1-3, bohlesUnknownyearautoregulationdynamicsof pages 24-28, charlaftis2014themekk1phd pages 1-2). | High for JNK–c-Jun and cleavage-dependent switching; broader outputs are cell- and stimulus-dependent. |
| Cancer | MAP3K1 is commonly altered as a putative tumor suppressor in luminal breast cancer: reported alterations were predominantly frameshift (59%) or nonsense (19%), and about 50% of tumors altered in MAP3K1 or MAP2K4 also carried activating PIK3CA mutations. Conversely, amplification or activated fragments can be pro-growth in other cancers. | Human tumor genomics and pathway genetics; experimental JNK deficiency accelerates HER2-driven tumors (itah2023her2drivenbreastcancer pages 1-2, pham2013map3k1genomicalterations pages 5-7, itah2023her2drivenbreastcancer pages 8-10). | High for context dependence and loss-of-function enrichment in luminal breast cancer. JNK-model findings are not direct proof of MAP3K1-specific tumor suppression in HER2-positive disease. |
| 46,XY DSD | Heterozygous, sex-limited gain-of-function MAP3K1 variants cause 46,XY gonadal dysgenesis/sex reversal, commonly increasing ERK and, to a lesser extent, p38 signaling and perturbing testis-versus-ovary developmental signaling. | Patient-derived cells and human genetic studies; MAP3K1 variants were reported in approximately 18% of sporadic 46,XY gonadal-dysgenesis cases in an influential cohort (lu2025anovelvariant pages 1-2, pham2013map3k1genomicalterations pages 4-5). | High disease association; signaling effects vary by variant, and the 18% estimate is not generalizable to every DSD population. |
| 2024 DFNB128 deafness | Homozygous kinase-domain variant c.4460G>A, p.Arg1487His segregated with severe-to-profound nonsyndromic sensorineural deafness in two siblings from one consanguineous family. The allele occurred in 3/1,613,810 population chromosomes and 0/348 ethnically matched control chromosomes. | Homozygosity mapping, exome sequencing, Sanger segregation, conservation/modeling, cochlear single-cell expression, and concordant deaf Map3k1 mouse models (faridi2024deafnessdfnb128associated pages 11-13, faridi2024deafnessdfnb128associated pages 10-11, faridi2024deafnessdfnb128associated pages 2-4, faridi2024deafnessdfnb128associated pages 6-8). | Moderate. Strong candidate association, but only one human family was reported; direct functional testing of Arg1487His and independent replication were lacking. |
Table: Concise evidence-based annotation of human MAP3K1/MEKK1 (Q13233), covering its identity, domains, dual catalytic activities, localization, pathways, and major disease associations. Confidence notes distinguish established mechanisms from context-dependent or incompletely replicated findings.
The supplied record is internally and externally consistent:
The retrieved human literature explicitly equates MAP3K1 with MEKK1 and reports the matching length, molecular mass, kinase identity, and unusual ubiquitin-ligase architecture. The target is therefore unambiguous for this report. (pham2013map3k1genomicalterations pages 1-3, bohlesUnknownyearautoregulationdynamicsof pages 24-28)
MAP3K1 has a large N-terminal regulatory region and a C-terminal protein-kinase domain, reported at residues 1243–1508. Its N-terminal region includes a SWIM zinc-binding domain, a structurally resolved TOG domain, and a RING-like domain historically called a PHD domain; tandem ubiquitin-interacting motifs precede the kinase region. A caspase-3 cleavage site at Asp878 separates much of the regulatory region from the C-terminal catalytic fragment. (pham2013map3k1genomicalterations pages 1-3, bohlesUnknownyearautoregulationdynamicsof pages 24-28, filipcik2020acryptictubulinbindinga pages 1-2)
This architecture aligns with the supplied InterPro assignments: ARM/HEAT-like helical folds are compatible with the six-HEAT-repeat TOG structure, while the C terminus belongs to the STE-family protein-kinase/MAP3K group. MAP3K1 is unusual among MAP3Ks because it combines a kinase with an intrinsic RING/PHD-like E3 ubiquitin ligase. (bohlesUnknownyearautoregulationdynamicsof pages 28-31, charlaftis2014themekk1phd pages 1-2)
MAP3K1 catalyzes the conventional protein-kinase reaction:
ATP + MAP2K protein → ADP + phosphorylated MAP2K protein.
The enzyme phosphorylates activation-loop serine/threonine residues in downstream MAP2Ks. Oligomerization supports trans-autophosphorylation and activation, although detailed catalytic constants and a universal short peptide-recognition consensus are not established by the retrieved evidence. (bohlesUnknownyearautoregulationdynamicsofa pages 169-173, lu2002thephddomain pages 2-3)
MKK4/MAP2K4 is the most strongly supported preferred kinase substrate. Biochemical work reports the greatest MEKK1 activity toward MKK4, which then activates JNK. MAP3K1 can also directly phosphorylate MKK1/MAP2K1, supporting ERK1/2 activation, and signaling through MKK7/MAP2K7 contributes to JNK activation. The physiologically dominant route is therefore best annotated as MAP3K1 → MKK4/MKK7 → JNK, with MKK1/2–ERK signaling treated as stimulus- and cellular-context-dependent rather than equally preferred. (lu2002thephddomain pages 2-3, witowsky2003ubiquitylationofmekk1 pages 1-2, charlaftis2014themekk1phd pages 1-2)
MAP3K1 does not phosphorylate c-Jun directly in the canonical cascade: MKK4 and MKK7 activate JNK, and JNK phosphorylates c-Jun. This distinction is important because MAP3K1 separately regulates c-Jun abundance through its E3-ligase activity. (bohlesUnknownyearautoregulationdynamicsof pages 24-28, xia2007mekk1mediatesthe pages 1-2)
The RING/PHD-like domain recruits a ubiquitin-charged E2 and promotes transfer of ubiquitin to substrate lysines. Unlike a HECT ligase, it functions primarily as an E2–substrate adaptor rather than forming a catalytic ubiquitin thioester. PHD/RING mutations markedly impair ubiquitylation, while intact kinase activity and full-length organization can also be required for efficient cellular autoubiquitylation. (lu2002thephddomain pages 3-5, xia2007mekk1mediatesthe pages 1-2, witowsky2003ubiquitylationofmekk1 pages 2-3)
Three mechanistically important substrates illustrate the range of outcomes:
ERK1/2: Under hyperosmotic stress, MAP3K1 associates with ERK1/2, polyubiquitylates it, and promotes proteasome-dependent degradation. MG132 prevented ERK loss, whereas MEK inhibition blocked ERK activation but not degradation, separating the proteolytic effect from conventional MEK–ERK activation. Purified-domain and cellular experiments supported direct ERK2 ubiquitylation and showed impairment by kinase- or PHD-defective MAP3K1. [Lu et al., Molecular Cell, May 2002; DOI: https://doi.org/10.1016/S1097-2765(02)00519-1]. (lu2002thephddomain pages 2-3, lu2002thephddomain pages 3-5)
c-Jun: During osmotic stress, MAP3K1 promotes c-Jun ubiquitylation and proteasomal degradation. In rat fibroblasts, c-Jun loss was evident by approximately 6 hours after sorbitol treatment; MAP3K1 deficiency blocked the response, and c-Jun overexpression reduced osmotic-stress-induced apoptosis. [Xia et al., Molecular and Cellular Biology, January 2007; DOI: https://doi.org/10.1128/MCB.01355-06]. (xia2007mekk1mediatesthe pages 1-2)
TAB1: MAP3K1 uses UBE2N–UBE2V1 to transfer predominantly Lys63-linked, nondegradative ubiquitin chains to TAB1. This promotes TAB1–TAK1 signaling and cytokine-induced JNK/p38 activation. An E3-defective Map3k1 knock-in impaired responses to TGF-β, EGF, and nocodazole without destabilizing the MAPKs, supporting a signaling rather than degradative mechanism. Much of this physiological evidence derives from mouse embryonic stem cells and should be extrapolated to human MAP3K1 cautiously. [Charlaftis et al., EMBO Journal, September 26, 2014; DOI: https://doi.org/10.15252/embj.201488351]. (charlaftis2014themekk1phd pages 1-2, charlaftis2014themekk1phd pages 2-3)
MAP3K1 ubiquitylation can also inhibit its own ability to phosphorylate MKK1 and MKK4. In HEK293 experiments, kinase-inactive MAP3K1 generated less than 10% of the wild-type ubiquitylation signal, and mutation of PHD residue Cys441 markedly reduced ubiquitylation. This provides an autoregulatory brake connecting the kinase and ubiquitin systems. [Witowsky and Johnson, Journal of Biological Chemistry, January 2003; DOI: https://doi.org/10.1074/jbc.C200616200]. (witowsky2003ubiquitylationofmekk1 pages 1-2, witowsky2003ubiquitylationofmekk1 pages 2-3)
The best-supported core pathway is:
cytoskeletal, osmotic, cytokine, receptor, or genotoxic stress → MAP3K1 → MKK4/MKK7 → JNK → c-Jun and other JNK substrates.
MAP3K1 additionally influences MKK1/2–ERK1/2, p38, TAK1, NF-κB, and p53-related signaling. These broader outputs should not be interpreted as constitutive: pathway selection depends on stimulus, binding partners, subcellular recruitment, ubiquitin-chain topology, and whether MAP3K1 remains full-length or is proteolytically cleaved. (pham2013map3k1genomicalterations pages 1-3, bohlesUnknownyearautoregulationdynamicsof pages 24-28, charlaftis2014themekk1phd pages 1-2)
MAP3K1 is particularly responsive to perturbations of cell shape and cytoskeletal dynamics. The cryptic TOG domain preferentially binds curved α/β-tubulin heterodimers, which occur in soluble tubulin and at polymerizing or depolymerizing microtubule ends. Its crystal structure contains six HEAT-repeat helix–loop–helix units. Mutations disrupting this interaction reduce microtubule density at the leading edge of polarized cells, providing a direct molecular bridge from microtubule state to MAP3K1 signaling and migration. [Filipčík et al., PNAS, August 2020; DOI: https://doi.org/10.1073/pnas.2006429117]. (bohlesUnknownyearautoregulationdynamicsof pages 28-31, filipcik2020acryptictubulinbindinga pages 1-2)
This mechanism is relevant to microtubule-targeting chemotherapy: such agents activate MAP3K1-dependent stress responses, while tumor-derived mutations recur at the TOG–tubulin interface. That observation is biologically suggestive but does not yet establish a clinically validated predictive biomarker. (bohlesUnknownyearautoregulationdynamicsof pages 28-31, filipcik2020acryptictubulinbindinga pages 1-2)
Full-length MAP3K1 often supports survival, migration, and organized stress adaptation. Caspase-3 cleavage at Asp878 releases a C-terminal kinase-containing fragment associated with sustained JNK signaling and apoptosis. Consequently, apparently contradictory survival and death phenotypes can reflect different stimuli, localization, signal duration, and proteolytic state rather than inconsistent enzyme function. (pham2013map3k1genomicalterations pages 1-3, filipcik2020acryptictubulinbindinga pages 1-2)
MAP3K1 is an intracellular, dynamically recruited signaling protein rather than a constitutive resident of one organelle. Reported locations include:
These locations position MAP3K1 to detect changes in adhesion, junction integrity, mechanical/cytoskeletal organization, and microtubule dynamics. Localization is partner- and stimulus-dependent; assigning it simply as “cytosolic” would omit a central feature of its regulation. (filipcik2020acryptictubulinbindinga pages 1-2, lu2002thephddomain pages 2-3, lu2002thephddomain pages 3-5)
The most defensible functional annotation is integration of stress and cytoskeletal inputs into MAPK and ubiquitin-dependent outputs controlling cell migration, epithelial morphogenesis, survival, and apoptosis. Developmental mouse genetics additionally supports roles in eyelid closure, ocular morphogenesis, immune-cell development, and auditory-system organization, but these pleiotropic phenotypes are downstream consequences of the core signaling mechanism rather than separate biochemical functions. (bohlesUnknownyearautoregulationdynamicsof pages 24-28, charlaftis2014themekk1phd pages 1-2)
Human genetics particularly supports a role in sex determination. Disease-associated heterozygous MAP3K1 variants often enhance RhoA-associated signaling and increase ERK phosphorylation, with a smaller increase in p38, shifting the balance between testis- and ovary-promoting developmental programs. These variants are generally interpreted as context-specific gain-of-function alleles, unlike the loss-of-function alterations frequent in luminal breast tumors. (lu2025anovelvariant pages 1-2, pham2013map3k1genomicalterations pages 4-5)
Faridi and colleagues reported homozygous MAP3K1 c.4460G>A, p.Arg1487His, affecting a highly conserved residue in the kinase domain, in two affected siblings from a consanguineous Pakistani family. The two siblings had severe-to-profound or profound bilateral sensorineural hearing loss; both parents and unaffected siblings were heterozygous carriers. The study used approximately 960,919 SNP markers, homozygosity mapping, exome sequencing, and Sanger confirmation. (faridi2024deafnessdfnb128associated pages 2-4, faridi2024deafnessdfnb128associated pages 6-8)
The allele was observed in only 3 of 1,613,810 population chromosomes and was absent from 348 ethnically matched control chromosomes. No convincing biallelic alternative was found among the other genes in the shared 1.2-Mb interval. Supporting evidence included conserved sequence/structural modeling, cochlear single-cell expression, and two recessive deaf Map3k1 mouse models. [Faridi et al., Genes 15:845, published June 2024; DOI: https://doi.org/10.3390/genes15070845]. (faridi2024deafnessdfnb128associated pages 11-13, faridi2024deafnessdfnb128associated pages 10-11, faridi2024deafnessdfnb128associated pages 6-8)
The evidence remains provisional: only one human family was identified, Arg1487His was not functionally tested in a direct kinase assay, and linkage disequilibrium with an undiscovered variant cannot be completely excluded. The correct annotation is therefore “strong candidate association with autosomal-recessive nonsyndromic deafness,” not yet an extensively replicated genotype–phenotype relationship. (faridi2024deafnessdfnb128associated pages 11-13, faridi2024deafnessdfnb128associated pages 10-11)
Itah et al. examined the pathway consequence expected from loss-of-function alterations in MAP3K1, MAP2K4, and MAP2K7. In human mammary epithelial cells, CRISPR disruption of MAPK8/MAPK9 or MAP2K4/MAP2K7 did not change two-dimensional growth but promoted continued proliferation and enlarged multi-acinar structures in three-dimensional culture. HER2 activation and JNK loss caused similar transcriptional changes. (itah2023her2drivenbreastcancer pages 1-2, itah2023her2drivenbreastcancer pages 8-10)
In mouse mammary epithelium, JNK or upstream MAP2K deficiency accelerated HER2-driven breast-tumor development. Genomic analyses compared six wild-type and seven JNK-deficient tumor lines; deficient tumors showed increased structural variation, including significantly more high-impact exon-associated inversions. [Itah et al., PNAS, published January 19, 2023; DOI: https://doi.org/10.1073/pnas.2218373120]. (itah2023her2drivenbreastcancer pages 1-2, itah2023her2drivenbreastcancer pages 8-10)
This is compelling pathway-level evidence that the MAP3K1–MKK4/7–JNK axis can suppress HER2-driven tumorigenesis. It is not, however, a MAP3K1-specific knockout study; therefore, it supports the functional interpretation of MAP3K1 loss but does not prove that every MAP3K1 alteration has the same phenotype. (itah2023her2drivenbreastcancer pages 10-11, itah2023her2drivenbreastcancer pages 8-10)
MAP3K1’s cancer role is strongly context-dependent. In luminal breast cancer, alterations are predominantly predicted loss-of-function: one reported spectrum comprised 59% frameshift insertions/deletions and 19% nonsense mutations, without a recurrent hotspot. Approximately 50% of tumors with MAP3K1 or MAP2K4 alterations also carried activating PIK3CA mutations, suggesting cooperating PI3K activation and JNK-pathway attenuation. Conversely, amplification or increased expression was reported in approximately 5% of melanomas, where activated C-terminal signaling may support ERK and proliferation. (pham2013map3k1genomicalterations pages 5-7)
Open Targets independently aggregates MAP3K1 associations with breast adenocarcinoma/carcinoma, ovarian cancer, 46,XY sex reversal, and partial gonadal dysgenesis. Such association scores are evidence-integration outputs rather than clinical actionability ratings. (OpenTargets Search: -MAP3K1)
The expert interpretation is therefore not “MAP3K1 is always oncogenic” or “always a tumor suppressor.” Full-length versus truncated protein, tissue lineage, mutation class, and pathway wiring determine the outcome. Inactivating mutations can suppress JNK-mediated tumor restraint in breast cancer, whereas amplification, cleavage, or sustained kinase output can be growth- or death-promoting elsewhere. (pham2013map3k1genomicalterations pages 1-3, itah2023her2drivenbreastcancer pages 1-2, pham2013map3k1genomicalterations pages 5-7)
Pathogenic heterozygous MAP3K1 variants are established causes of 46,XY gonadal dysgenesis/sex reversal. An influential cohort estimated MAP3K1 variants in about 18% of sporadic 46,XY gonadal-dysgenesis cases, although this frequency should not be generalized across ancestries or differently ascertained DSD cohorts. Patient-derived cells showed increased ERK and, to a lesser degree, p38 phosphorylation; implicated variants cluster in regulatory interaction regions and can enhance RhoA binding. (lu2025anovelvariant pages 1-2, pham2013map3k1genomicalterations pages 4-5)
The 2024 DFNB128 report expands the allelic model: dominant regulatory gain-of-function variants are associated with sex-development phenotypes, whereas a subtle homozygous kinase-domain variant may cause isolated deafness. Mouse cochlear data support MAP3K1 expression in spiral-ganglion and epithelial/supporting-cell populations, but the precise human cellular lesion remains unresolved. (faridi2024deafnessdfnb128associated pages 10-11, faridi2024deafnessdfnb128associated pages 2-4, faridi2023deafnessdfnb110associated pages 7-10)
MAP3K1 is already relevant to diagnostic sequencing and variant interpretation in 46,XY DSD, breast-tumor genomic profiling, and potentially recessive hearing-loss panels. Interpretation must be allele-specific: truncating somatic cancer variants, regulatory DSD gain-of-function variants, and homozygous kinase-domain variants should not be assigned a common mechanism. The 2024 deafness association requires independent replication before it can support high-confidence clinical action on its own. (faridi2024deafnessdfnb128associated pages 10-11, pham2013map3k1genomicalterations pages 4-5, pham2013map3k1genomicalterations pages 5-7)
MAP3K1 or MAP2K4 loss can identify tumors with attenuated JNK signaling, particularly in luminal breast cancer, and may help define biological subgroups alongside PIK3CA status. At present, the evidence supports mechanistic stratification and research use more strongly than a standard MAP3K1-directed treatment decision. (itah2023her2drivenbreastcancer pages 1-2, pham2013map3k1genomicalterations pages 5-7)
Potential intervention points include the C-terminal kinase, the TOG–tubulin interface, the RING/E2 interaction, and downstream JNK or ERK nodes. Direct systemic inhibition is intrinsically risky because MAP3K1 can be tumor-suppressive, pro-survival, or pro-apoptotic depending on tissue and stimulus. A successful strategy would likely require genotype-, lineage-, and pathway-state selection rather than indiscriminate MAP3K1 blockade. The retrieved 2023–2024 literature does not establish an approved MAP3K1-selective therapy or a validated clinical companion biomarker.
Recommended primary annotation:
Human MAP3K1/MEKK1 is a dynamically localized STE-family MAP kinase kinase kinase and RING-type E3 ubiquitin ligase. It preferentially phosphorylates MKK4 and activates MKK4/MKK7–JNK signaling in response to cytoskeletal and cellular stress, while contextually coupling to MKK1/2–ERK and p38/TAK1 pathways. Its SWIM/TOG/RING-containing regulatory region recruits cytoskeletal and ubiquitin-system components; its TOG domain binds curved tubulin, and its RING/PHD-like domain ubiquitylates ERK1/2, c-Jun, TAB1, and MAP3K1 itself. Spatial recruitment and caspase cleavage determine whether signaling favors migration/survival or apoptosis.
Confidence: high for identity, kinase/E3 dual activity, MKK4 preference, JNK coupling, TOG–tubulin binding, and stress-dependent ERK/c-Jun/TAB1 ubiquitylation; moderate for the relative importance of ancillary pathways in any one human tissue; provisional for MAP3K1 p.Arg1487His as a replicated human deafness allele.
References
(pham2013map3k1genomicalterations pages 1-3): T. T. Pham, Steven P. Angus, and G. Johnson. Map3k1: genomic alterations in cancer and function in promoting cell survival or apoptosis. Genes & cancer, 4 11-12:419-26, Nov 2013. URL: https://doi.org/10.1177/1947601913513950, doi:10.1177/1947601913513950. This article has 163 citations.
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(lu2002thephddomain pages 2-3): Zhimin Lu, Shuichan Xu, Claudio Joazeiro, Melanie H Cobb, and Tony Hunter. The phd domain of mekk1 acts as an e3 ubiquitin ligase and mediates ubiquitination and degradation of erk1/2. Molecular cell, 9 5:945-56, May 2002. URL: https://doi.org/10.1016/s1097-2765(02)00519-1, doi:10.1016/s1097-2765(02)00519-1. This article has 415 citations and is from a highest quality peer-reviewed journal.
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(xia2007mekk1mediatesthe pages 1-2): Yan Xia, Ji Wang, Shuichan Xu, Gary L. Johnson, Tony Hunter, and Zhimin Lu. Mekk1 mediates the ubiquitination and degradation of c-jun in response to osmotic stress. Jan 2007. URL: https://doi.org/10.1128/mcb.01355-06, doi:10.1128/mcb.01355-06. This article has 95 citations and is from a domain leading peer-reviewed journal.
(charlaftis2014themekk1phd pages 1-2): Nikolaos Charlaftis, Tesha Suddason, Xuefeng Wu, Saba Anwar, Michael Karin, and Ewen Gallagher. The mekk1 phd ubiquitinates tab1 to activate mapks in response to cytokines. The EMBO Journal, 33:2581-2596, Sep 2014. URL: https://doi.org/10.15252/embj.201488351, doi:10.15252/embj.201488351. This article has 58 citations.
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