Affinage

MARK3

MAP/microtubule affinity-regulating kinase 3 · UniProt P27448

Length
753 aa
Mass
84.4 kDa
Annotated
2026-06-10
26 papers in source corpus 15 papers cited in narrative 15 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 9/9 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

MARK3 (C-TAK1/PAR-1A) is a serine/threonine kinase that governs the subcellular localization and activity of diverse substrates by phosphorylating them to generate 14-3-3 binding sites, thereby coordinating cell cycle control, Ras-MAPK signaling, cell polarity, and Hippo-pathway tumor suppression (PMID:9543386, PMID:12941695, PMID:29089450). Its founding activity is phosphorylation of Cdc25C on Ser216, which creates a 14-3-3 docking site that retains Cdc25C in the cytoplasm during interphase (PMID:9543386). The same 14-3-3-priming logic extends across substrates: it phosphorylates KSR1 on Ser392 to sequester the scaffold in the cytoplasm until growth-factor signaling relieves the modification and permits MEK/MAPK activation (PMID:11741534), phosphorylates plakophilin 2 to influence its localization (PMID:12941695), and primes class IIa HDACs (e.g. HDAC7 Ser155) to drive their nuclear export and relieve transcriptional repression (PMID:16980613). Stable substrate docking through defined sequence motifs is a prerequisite for productive phosphorylation (PMID:12941695). Through the LKB1–MARK3 axis, it phosphorylates ARHGEF2 on Ser151, releasing it from microtubules to activate RHOA and establish epithelial polarity (PMID:29089450), and phosphorylates CDC25B/CDC25C to enforce G2/M arrest under metabolic stress (PMID:35017636). In the Hippo pathway, MARK2/MARK3 phosphorylate NF2 and YAP/TAZ to reverse the action of LATS1/2 and sustain YAP/TAZ coactivator function, a dependency exploited for tumor regression (PMID:39058094, PMID:40858196). MARK3 activity is itself negatively regulated by Pim-1, which binds and phosphorylates MARK3 to dampen its Cdc25C-directed activity (PMID:15319445), and its UBA domain has evolved to make an intramolecular contact with the kinase domain rather than to bind ubiquitin (PMID:17726107). At the organismal level, MARK3 loss alters energy metabolism and gluconeogenesis (PMID:20733003), increases bone mass via Jag1/Notch–JNK signaling in osteoblasts (PMID:33792563), and is required for eye development (PMID:29771303).

Mechanistic history

Synthesis pass · year-by-year structured walk · 13 steps
  1. 1998 High

    Established MARK3's founding biochemical activity by showing it phosphorylates Cdc25C to create a 14-3-3 docking site, defining a mechanism for spatial control of a cell-cycle phosphatase.

    Evidence In vitro kinase assay, COS-7 cotransfection, bacterial co-production reconstitution, and Co-IP of C-TAK1 with Cdc25C

    PMID:9543386

    Open questions at the time
    • Did not address whether other substrates share the 14-3-3-priming mechanism
    • Cellular consequences for checkpoint timing not fully resolved
  2. 2001 High

    Generalized the 14-3-3-priming model to Ras-MAPK signaling by showing MARK3 phosphorylates KSR1 Ser392 to sequester the scaffold until growth-factor stimulation, linking the kinase to control of MEK/MAPK activation.

    Evidence Co-IP, in vitro kinase assay, translocation imaging, and mutational analysis in cells

    PMID:11741534

    Open questions at the time
    • Upstream signal that reduces S392 phosphorylation not identified
    • Phosphatase reversing the site unknown
  3. 2003 High

    Defined the requirement for stable substrate docking and broadened the substrate set, showing motif-dependent association is needed for phosphorylation and identifying PKP2 as a new substrate.

    Evidence Mutational disruption of docking, in vivo phosphorylation assays, Co-IP, and subcellular localization for KSR1, Cdc25C, and PKP2

    PMID:12941695

    Open questions at the time
    • Structural basis of motif recognition not resolved
    • Functional consequence of PKP2 phosphorylation at junctions not fully defined
  4. 2004 High

    Identified upstream negative regulation of MARK3, showing Pim-1 binds and phosphorylates it to suppress its Cdc25C-directed activity and modulate its nuclear localization.

    Evidence Co-IP, yeast two-hybrid, mass spectrometry, in vitro kinase assay, and immunofluorescence

    PMID:15319445

    Open questions at the time
    • Physiological contexts where Pim-1 controls MARK3 not established
    • Whether other substrate outputs are equally suppressed unknown
  5. 2006 High

    Extended MARK3 substrate scope to transcriptional control, showing MARK/Par-1 kinases prime class IIa HDACs for signal-independent nuclear export via hierarchical 14-3-3 site phosphorylation.

    Evidence In vitro kinase assay, phospho-site mutagenesis, localization studies, and reporter assays on HDAC7

    PMID:16980613

    Open questions at the time
    • Relative contributions of MARK3 versus MARK2 in vivo not separated
    • Target gene programs affected not enumerated
  6. 2007 High

    Resolved the function of the unusual UBA domain, showing it makes an intramolecular contact with the kinase domain rather than binding ubiquitin, reframing a domain previously presumed to be a ubiquitin sensor.

    Evidence X-ray crystallography of linked kinase–UBA domains plus solution NMR dynamics and titration

    PMID:17726107

    Open questions at the time
    • Functional impact of the UBA–kinase contact on catalytic regulation in cells not tested
    • Whether the contact modulates activation by upstream kinases unknown
  7. 2010 Medium

    Connected MARK3 to differentiation gene programs, implicating it in osteoclast gene expression through Mitf and revealing distinct, non-redundant metabolic roles for MARK3 versus MARK2 in vivo.

    Evidence Co-IP, kinase-dead and interaction-mutant reporter assays (Mitf); knockout mouse metabolic phenotyping and double-knockout epistasis (metabolism)

    PMID:20214879 PMID:20733003

    Open questions at the time
    • Direct Mitf phosphorylation by MARK3 not demonstrated
    • Molecular substrates underlying the metabolic phenotype not identified
  8. 2014 High

    Showed MARK3 regulates a phosphatase complex, phosphorylating the PP-1 inhibitor-2 subunit to modulate phosphatase activity and block GSK-3-directed phosphorylation.

    Evidence Reconstituted in vitro kinase assay with purified C-TAK1, mass spectrometry, and phosphatase activity assay

    PMID:25028520

    Open questions at the time
    • Cellular and physiological consequences of I-2 Ser71 phosphorylation not established
    • Whether this feeds into known MARK3 substrate pathways unknown
  9. 2017 High

    Defined the LKB1–MARK3–ARHGEF2–RHOA polarity axis, showing MARK3 phosphorylation of ARHGEF2 releases it from microtubules to drive RhoA activation and epithelial organization.

    Evidence In vitro kinase assay, Co-IPs, phospho-specific antibodies, loss-of-function, and 3D epithelial polarity culture

    PMID:29089450

    Open questions at the time
    • How LKB1 activates MARK3 mechanistically not detailed
    • Tissue-specific relevance of the axis not mapped
  10. 2018 Medium

    Demonstrated an evolutionarily conserved developmental requirement, linking MARK3/par-1 loss-of-function to defective eye development and a patient-equivalent disease variant.

    Evidence Drosophila knockdown and transgenic patient-equivalent mutation, ERG recordings, and immunohistochemistry

    PMID:29771303

    Open questions at the time
    • Causation in human patients rests on ortholog modeling
    • Substrate(s) underlying the eye phenotype not identified
  11. 2021 High

    Placed MARK3 upstream of Jag1/Notch–JNK signaling in bone, showing its loss increases osteoblast mineralization and bone mass through reduced Jag1 expression, with rescue by Jag1.

    Evidence Conditional/global knockout mice, RNA profiling, in vitro mineralization, and Jag1 overexpression rescue in vivo and in vitro

    PMID:33792563

    Open questions at the time
    • Direct MARK3 substrate controlling Jag1 expression not identified
    • Mechanism linking kinase activity to Notch ligand transcription unresolved
  12. 2024 High

    Established MARK2/MARK3 as direct positive regulators of YAP/TAZ that counteract Hippo kinases, identifying a druggable tumor dependency.

    Evidence Paralog cotargeting CRISPR screens, direct kinase assays on NF2 and YAP/TAZ, and in vivo tumor regression with CagA-mediated MARK2/3 inhibition

    PMID:39058094

    Open questions at the time
    • Precise phosphosites on NF2/YAP/TAZ and their 14-3-3 relationship not fully detailed here
    • Selectivity of MARK3 versus MARK2 in different tumors not separated
  13. 2025 Medium

    Embedded MARK3 in a pharmacologically actionable PTPN14–LATS1–MARK3 complex that promotes cytoplasmic YAP sequestration, linking a small molecule (fenofibrate) to Hippo control via MARK3.

    Evidence Direct binding assay, Co-IP/pulldown complex formation, genetic knockdown, pharmacological MARK3 inhibition, and YAP localization assay

    PMID:40858196

    Open questions at the time
    • Single-study complex without reciprocal structural validation
    • Direct MARK3 catalytic contribution within the complex not fully delineated
    • Apparent contrast with MARK3 sustaining YAP/TAZ function elsewhere not reconciled

Open questions

Synthesis pass · forward-looking unresolved questions
  • How upstream activation (e.g. by LKB1) and negative regulation (e.g. by Pim-1) are integrated to dictate which substrate-specific output MARK3 executes in a given cell remains unresolved.
  • No unified model of substrate selection across cell-cycle, polarity, and Hippo outputs
  • Structural basis of substrate docking-motif recognition undefined
  • Context determining whether MARK3 promotes or restrains YAP activity unclear

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0140096 catalytic activity, acting on a protein 8 GO:0016740 transferase activity 4 GO:0140110 transcription regulator activity 2
Localization
GO:0005829 cytosol 3 GO:0005634 nucleus 2 GO:0005856 cytoskeleton 1
Pathway
R-HSA-162582 Signal Transduction 4 R-HSA-1266738 Developmental Biology 2 R-HSA-1640170 Cell Cycle 2 R-HSA-74160 Gene expression (Transcription) 2 R-HSA-1430728 Metabolism 1
Partners
ARHGEF2CDC25CKSR1MITFNF2PIM1PKP2PTPN14
Complex memberships
PP-1I (protein phosphatase 1I)PTPN14–LATS1–MARK3 complex

Evidence

Reading pass · 15 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
1998 C-TAK1 (MARK3) phosphorylates human Cdc25C on serine 216 in vitro and in vivo, generating a 14-3-3 protein binding site that mediates cytoplasmic retention of Cdc25C throughout interphase. A physical interaction between C-TAK1 and Cdc25C was demonstrated, and coproduction in bacteria resulted in stoichiometric phosphorylation of Ser216 and facilitated 14-3-3 binding in vitro. In vitro kinase assay, cotransfection in COS-7 cells, bacterial co-production reconstitution, Co-IP Cell growth & differentiation High 9543386
2001 C-TAK1 (MARK3) constitutively associates with KSR1 and phosphorylates serine 392 of KSR1, creating a 14-3-3 binding site that sequesters KSR1 in the cytoplasm in unstimulated cells. Upon growth factor signaling, phosphorylation of S392 is reduced, allowing KSR1 to translocate to the plasma membrane and facilitate MEK/MAPK activation. Co-immunoprecipitation, in vitro kinase assay, cell imaging/translocation assay, mutational analysis Molecular cell High 11741534
2003 C-TAK1 (MARK3) requires specific sequence motifs for stable substrate association and phosphorylation. Disruption of C-TAK1 binding to KSR1 abolished 14-3-3-binding site phosphorylation in vivo and caused constitutive plasma membrane localization of KSR1 with increased biological activity. Disruption of Cdc25C–C-TAK1 interaction reduced 14-3-3-binding site phosphorylation and caused nuclear accumulation of Cdc25C in interphase. Additionally, plakophilin 2 (PKP2) was identified as a novel C-TAK1 substrate; its phosphorylation by C-TAK1 generates a 14-3-3 binding site that influences PKP2 localization. Mutational analysis, in vivo phosphorylation assays, co-immunoprecipitation, subcellular localization studies The EMBO journal High 12941695
2004 Pim-1 kinase physically interacts with C-TAK1 (MARK3) and phosphorylates it at sites distinct from C-TAK1 autophosphorylation sites, significantly decreasing C-TAK1 kinase activity, particularly its ability to phosphorylate Cdc25C. Pim-1/C-TAK1 complexes are predominantly cytoplasmic, but nuclear Pim-1 can recruit C-TAK1 to the nucleus. Co-immunoprecipitation, yeast two-hybrid, mass spectrometry, in vitro kinase assay, immunofluorescence The Journal of biological chemistry High 15319445
2006 C-TAK1 (MARK3) and EMK (MARK2), two MARK/Par-1 family members, phosphorylate class IIa HDACs (exemplified by HDAC7) on 14-3-3 binding sites, promoting signal-independent nuclear export. Specifically, MARK/Par-1 kinases phosphorylate the most N-terminal serine (Ser155 of HDAC7), which is a prerequisite for hierarchical phosphorylation of the adjacent 14-3-3 site (Ser181), altering subcellular localization and repressive function of class IIa HDACs. In vitro kinase assay, subcellular localization studies, phosphorylation site mutagenesis, functional reporter assays Molecular and cellular biology High 16980613
2007 The MARK3 UBA domain forms a stable intramolecular interaction with the N-terminal lobe of the kinase domain, as revealed by X-ray crystal structure of the linked hMARK3 kinase and UBA domains. NMR dynamics showed the isolated UBA domain is highly dynamic, undergoing folding-unfolding equilibrium that attenuates ubiquitin binding despite presence of canonical ubiquitin-recognition residues. The UBA domain has thus evolved to bind the kinase domain (stabilizing an open conformation of its lobes) at the expense of ubiquitin engagement. X-ray crystallography, solution NMR dynamics, NMR titration experiments Proceedings of the National Academy of Sciences of the United States of America High 17726107
2010 C-TAK1 (MARK3) interacts with microphthalmia-associated transcription factor (Mitf) but not the related family member Tfe3. Overexpression of C-TAK1 inhibits expression of Acp5, while a kinase-dead C-TAK1 or a Mitf mutant unable to interact with C-TAK1 increases Acp5 expression, indicating C-TAK1 regulates osteoclast differentiation gene expression through Mitf. Protein phosphatase 2A catalytic subunit is upregulated during M-CSF/RANKL signaling, suggesting it dephosphorylates Mitf to allow nuclear translocation. Co-immunoprecipitation, kinase-dead mutant, reporter assays, immunofluorescence Biochemical and biophysical research communications Medium 20214879
2010 Genetic knockout of Par-1a/MARK3/C-TAK1 in mice leads to increased energy expenditure, reduced adiposity, resistance to hepatic steatosis, defective gluconeogenesis (complete hepatic glycogen depletion upon starvation, hypoketotic hypoglycemia), and increased glycogen synthase levels. Intercrossing with Par-1b/MARK2 knockout mice revealed at least one of four alleles is necessary for embryonic survival, establishing genetic non-redundancy of MARK3 and MARK2 in distinct metabolic processes. Knockout mouse model, metabolic phenotyping, epistasis analysis via double knockout intercrossing Molecular and cellular biology High 20733003
2014 C-TAK1 (MARK3) phosphorylates the inhibitor-2 (I-2) regulatory subunit of protein phosphatase 1I (PP-1I) on Ser-71, resulting in partial inhibition of ATP-dependent phosphatase activity and inhibition of subsequent phosphorylation of Thr-72 by GSK-3. C-TAK1 was identified as a physical component of purified brain PP-1I by mass spectrometry. In vitro reconstitution kinase assay with purified C-TAK1, mass spectrometry identification, phosphatase activity assay The Journal of biological chemistry High 25028520
2017 LKB1 activates MARK3, which directly phosphorylates ARHGEF2 at Ser151. This phosphorylation creates a 14-3-3 binding site in ARHGEF2, disrupting its interaction with DYNLT1 and causing ARHGEF2 to dissociate from microtubules. Released ARHGEF2 activates RHOA, stimulating stress fiber and focal adhesion formation, and is required for organized epithelial cell polarity in 3D culture. PP2A dephosphorylates Ser151 to restore the inhibited state. In vitro kinase assay, Co-immunoprecipitation, phospho-specific antibodies, loss-of-function experiments, 3D cell culture, subcellular localization Science signaling High 29089450
2018 Loss-of-function of MARK3 (equivalent to par-1 p.Arg792Gly mutation) in Drosophila eye development leads to significant reduction in eye size, severe loss of photoreceptors, and loss of vision by ERG, demonstrating an evolutionarily conserved role of MARK3/par-1 in eye development. The equivalent human variant (p.Arg570Gly) was identified in patients with congenital vision loss and progressive eye degeneration. Drosophila knockdown, transgenic expression of patient-equivalent mutation, ERG recordings, immunohistochemistry Human molecular genetics Medium 29771303
2021 Mark3-deficient osteoblasts exhibit greater matrix mineralization with reduced Jag1/Hes1 expression and diminished downstream JNK signaling. Overexpression of Jag1 in Mark3-deficient osteoblasts in vitro and in vivo normalized mineralization and bone mass, placing MARK3 upstream of Jag1/Notch–JNK signaling in osteoblasts. Mice lacking Mark3 globally or selectively in osteoblasts have increased bone mass. Conditional and global knockout mice, RNA profiling, in vitro mineralization assay, Jag1 overexpression rescue in vivo and in vitro The Journal of clinical investigation High 33792563
2022 Activation of the LKB1–MARK3 axis by metabolic stress leads to phosphorylation of CDC25B and CDC25C, followed by G2/M phase arrest in ovarian carcinoma cells, suppressing proliferation and angiogenesis. MARK3 overexpression attenuates cell cycle progression and angiogenesis partly through downregulation of AP-1 and Hippo signaling target genes. MARK3 overexpression in cell lines, phosphorylation assays, RNA-seq, ATAC-seq, cell cycle analysis Communications biology Medium 35017636
2024 MARK2/MARK3 are required for YAP/TAZ transcriptional coactivator function in diverse carcinoma and sarcoma cells, identified via paralog cotargeting CRISPR screens. Mechanistically, MARK2/3 directly phosphorylate NF2 and YAP/TAZ, which effectively reverses the tumor-suppressive activity of Hippo module kinases LATS1/2. Catalytic inhibition of MARK2/3 using the CagA protein from H. pylori regressed established tumors in vivo. Paralog cotargeting CRISPR screens, in vitro phosphorylation assays, direct kinase assay with NF2/YAP/TAZ substrates, in vivo tumor regression with CagA inhibitor Cancer discovery High 39058094
2025 Fenofibrate (FF) directly binds the PPxY motif of PTPN14, facilitating formation of a PTPN14–LATS1–MARK3 complex that promotes cytoplasmic sequestration of YAP. Genetic knockdown of PTPN14 or pharmacological inhibition of MARK3 substantially abolished FF-mediated inhibition of malignant phenotypes, placing MARK3 within the PTPN14/MARK3/Hippo signaling axis. Direct binding assay, complex formation (Co-IP/pulldown), genetic knockdown, pharmacological inhibition, YAP localization assay Pharmacological research Medium 40858196

Source papers

Stage 0 corpus · 26 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2001 C-TAK1 regulates Ras signaling by phosphorylating the MAPK scaffold, KSR1. Molecular cell 242 11741534
1998 C-TAK1 protein kinase phosphorylates human Cdc25C on serine 216 and promotes 14-3-3 protein binding. Cell growth & differentiation : the molecular biology journal of the American Association for Cancer Research 214 9543386
2004 The oncogenic serine/threonine kinase Pim-1 phosphorylates and inhibits the activity of Cdc25C-associated kinase 1 (C-TAK1): a novel role for Pim-1 at the G2/M cell cycle checkpoint. The Journal of biological chemistry 123 15319445
2014 MARK4 and MARK3 associate with early tau phosphorylation in Alzheimer's disease granulovacuolar degeneration bodies. Acta neuropathologica communications 90 24533944
2001 Isolation of a novel human gene, MARKL1, homologous to MARK3 and its involvement in hepatocellular carcinogenesis. Neoplasia (New York, N.Y.) 90 11326310
2016 Integrating GWAS and Co-expression Network Data Identifies Bone Mineral Density Genes SPTBN1 and MARK3 and an Osteoblast Functional Module. Cell systems 89 27866947
2006 New role for hPar-1 kinases EMK and C-TAK1 in regulating localization and activity of class IIa histone deacetylases. Molecular and cellular biology 60 16980613
2003 Functional analysis of C-TAK1 substrate binding and identification of PKP2 as a new C-TAK1 substrate. The EMBO journal 59 12941695
2019 PCC0208017, a novel small-molecule inhibitor of MARK3/MARK4, suppresses glioma progression in vitro and in vivo. Acta pharmaceutica Sinica. B 53 32082974
2007 Conformational instability of the MARK3 UBA domain compromises ubiquitin recognition and promotes interaction with the adjacent kinase domain. Proceedings of the National Academy of Sciences of the United States of America 47 17726107
2017 MARK3-mediated phosphorylation of ARHGEF2 couples microtubules to the actin cytoskeleton to establish cell polarity. Science signaling 46 29089450
2010 Loss of Par-1a/MARK3/C-TAK1 kinase leads to reduced adiposity, resistance to hepatic steatosis, and defective gluconeogenesis. Molecular and cellular biology 42 20733003
2022 The metabolic stress-activated checkpoint LKB1-MARK3 axis acts as a tumor suppressor in high-grade serous ovarian carcinoma. Communications biology 21 35017636
2018 Visual impairment and progressive phthisis bulbi caused by recessive pathogenic variant in MARK3. Human molecular genetics 21 29771303
2024 MARK2/MARK3 Kinases Are Catalytic Codependencies of YAP/TAZ in Human Cancer. Cancer discovery 20 39058094
2007 Upregulation of Mark3 and Rpgrip1 mRNA expression by jujuboside A in mouse hippocampus. Acta pharmacologica Sinica 17 17302994
2022 MARK3 kinase: Regulation and physiologic roles. Cellular signalling 12 36581219
2021 Genomic variants within chromosome 14q32.32 regulate bone mass through MARK3 signaling in osteoblasts. The Journal of clinical investigation 9 33792563
2010 C-TAK1 interacts with microphthalmia-associated transcription factor, Mitf, but not the related family member Tfe3. Biochemical and biophysical research communications 9 20214879
2010 High expression stability of microtubule affinity regulating kinase 3 (MARK3) makes it a reliable reference gene. IUBMB life 8 20087965
2025 Clinical data investigation identifies MARK3 as an oncogenic driver in castration-resistant prostate cancer. Biochemistry and biophysics reports 6 40248134
2014 Regulation of protein phosphatase 1I by Cdc25C-associated kinase 1 (C-TAK1) and PFTAIRE protein kinase. The Journal of biological chemistry 5 25028520
2023 Kinome profiling identifies MARK3 and STK10 as potential therapeutic targets in uveal melanoma. The Journal of biological chemistry 4 37923138
2023 CircUBXN7 Impedes Apoptosis to Alleviate Myocardial Infarction Injury by Regulating the miR-582-3p/MARK3 Axis. Annals of clinical and laboratory science 3 37094856
2024 Interaction between MARK3 (rs11623869), PLCB4 (rs6086746) and GEMIN2 (rs2277458) variants with bone mineral density and serum 25-hidroxivitamin D levels in Mexican Mestizo women. Frontiers in endocrinology 2 38715801
2025 Fenofibrate-mediated inhibition of tumor proliferation and progression by modulating the PTPN14/MARK3/Hippo signaling axis. Pharmacological research 0 40858196

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