Affinage

MISP

Mitotic interactor and substrate of PLK1 · UniProt Q8IVT2

Length
679 aa
Mass
75.4 kDa
Annotated
2026-06-10
23 papers in source corpus 16 papers cited in narrative 15 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

MISP (C19orf21/Caprice) is a cell-cycle-regulated, direct actin-binding and F-actin-bundling protein that couples cortical actin organization to mitotic spindle positioning and, in epithelia, to microvillar architecture (PMID:23509069, PMID:24475924, PMID:35443169). During mitosis it is phosphorylated by Plk1 and Cdk1 and localizes to the cell cortex and retraction fibers, where it forms complexes with EB1 and p150(glued)/dynactin to stabilize cortical and astral microtubule attachments and orient the spindle; its depletion causes mitotic arrest, reduced inter-kinetochore tension, chromosome misalignment, and randomized spindle orientation (PMID:23509069, PMID:23574715). MISP acts within a defined cortical pathway: it functions downstream of ezrin—which competes with MISP for cortical actin-binding sites—and upstream of NuMA, and it recruits IQGAP1 to engage active Cdc42 and control p150(glued) distribution (PMID:29669740, PMID:29679050). Cell-cycle-dependent phosphorylation differentially tunes its biochemistry, with interphase sites enhancing bundling activity and mitotic sites suppressing actin binding (PMID:34023777). In transporting epithelia MISP preferentially binds ADP-actin near filament pointed ends, confining it to microvillar rootlets where it drives rootlet elongation and recruits fimbrin, a localization enforced by ezrin exclusion from the distal core bundle (PMID:35443169, PMID:38588808, PMID:37205433). Beyond the cytoskeleton, MISP binds the SARAH domain of MST1/2 to block their homodimerization and autophosphorylation, suppressing Hippo signaling and sustaining YAP activity, which in turn transcriptionally upregulates MISP in a feedback loop (PMID:40019375, PMID:41249743).

Mechanistic history

Synthesis pass · year-by-year structured walk · 9 steps
  1. 2013 High

    Established MISP as a mitotic effector by identifying it as a Plk1/Cdk1 substrate that links the actin cortex to spindle positioning, answering how cortical actin couples to astral microtubules.

    Evidence siRNA depletion, Plk1/Cdk1 phosphorylation assays, Co-IP of MISP with p150(glued) and EB1, live-cell spindle imaging and kinetochore tension measurements in cultured cells

    PMID:23509069 PMID:23574715

    Open questions at the time
    • Phospho-site identities and how they alter MISP localization were not mapped
    • Direct vs. indirect nature of the EB1/p150(glued) interactions not resolved structurally
  2. 2014 High

    Demonstrated that MISP is a direct multivalent actin-binding protein that bundles F-actin, establishing the biochemical basis for its cytoskeletal role independent of mitosis.

    Evidence In vitro F-actin bundling assays with purified protein plus overexpression/knockdown morphological phenotypes in cultured cells

    PMID:24475924

    Open questions at the time
    • Number and location of actin-binding sites not defined
    • Filament polarity of bundles not addressed
  3. 2018 High

    Placed MISP within an ordered cortical spindle-orientation pathway, showing it acts downstream of ezrin (via actin-site competition) and engages IQGAP1–Cdc42 to control NuMA and p150(glued).

    Evidence Co-IP (MISP–ezrin, MISP–IQGAP1, IQGAP1–Cdc42), siRNA epistasis, active-Cdc42 pull-down, IQGAP1 rescue, live imaging of NuMA and astral microtubules

    PMID:29669740 PMID:29679050

    Open questions at the time
    • How active Cdc42 feeds back onto microtubule capture not mechanistically detailed
    • Structural basis of the MISP–IQGAP1 interaction unknown
  4. 2021 High

    Resolved how the cell cycle reprograms MISP function by mapping phospho-sites that separately tune bundling versus binding activities.

    Evidence Site-directed mutagenesis of S394/S395/S400 and S376/S471/S541, in vitro actin-binding/bundling assays, phosphomutant overexpression with morphology readout

    PMID:34023777

    Open questions at the time
    • Kinases for each interphase/mitotic site not all assigned
    • Quantitative contribution of each site in vivo not established
  5. 2022 High

    Defined MISP's epithelial role by showing it localizes to and elongates microvillar actin rootlets and recruits fimbrin, with ezrin competition confining it to the basal pointed-end side.

    Evidence Immunofluorescence/live imaging, in vitro bundling and co-sedimentation with purified protein, siRNA/CRISPR KO with rootlet-length phenotype, ezrin loss-of-function

    PMID:35443169

    Open questions at the time
    • What terminates rootlet elongation not defined
    • Relationship between mitotic cortical role and epithelial microvillar role not unified
  6. 2022 Medium

    Provided in vivo physiological context, showing MISP supports intestinal epithelial recovery from inflammation partly via TGF-β1.

    Evidence MISP-knockout mouse DSS colitis model, RT-qPCR for Tgfb1, crypt histology and Ki67 staining

    PMID:36596561

    Open questions at the time
    • Mechanism linking MISP to Tgfb1 expression not reconstituted
    • Single lab; cell-type-specific contribution unresolved
  7. 2024 High

    Explained the molecular basis of MISP's nucleotide-state-selective actin engagement, showing it binds ADP-actin near pointed ends and assembles polarity-defined bundles, accounting for its rootlet targeting.

    Evidence In vitro TIRF microscopy with purified MISP and differentially nucleotide-loaded actin, cofilin immunostaining of native intestine, solution vs. substrate-attached bundling assays

    PMID:37205433 PMID:38588808

    Open questions at the time
    • Structural determinant of ADP-actin preference unknown
    • How phospho-regulation intersects with nucleotide-state selectivity not tested
  8. 2024 High

    Uncovered a non-cytoskeletal signaling function: MISP directly inhibits MST1/2 to suppress Hippo signaling and sustain YAP, forming a YAP→MISP positive feedback loop linked to ferroptosis protection.

    Evidence Co-IP (MISP–MST1/2), R390/391A binding-disruption mutant, in vitro autophosphorylation assay, siRNA with ferroptosis readout, in vivo xenograft

    PMID:40019375 PMID:41249743

    Open questions at the time
    • Whether actin binding and MST1/2 binding are mutually exclusive not determined
    • Structural detail of MISP–SARAH domain contact not solved
  9. 2024 Medium

    Extended MISP into additional cancer signaling axes (IQGAP1/STAT3/PD-L1, Wnt/β-catenin, JAK2-STAT3, OIP5), implicating it in immune escape and proliferation.

    Evidence Co-IP of MISP–IQGAP1–STAT3 and MISP–OIP5 complexes, β-catenin nuclear localization Westerns, MISP-deficient mouse tumor models, xenografts

    PMID:37633233 PMID:38057358 PMID:38474305 PMID:39278512

    Open questions at the time
    • Direct biochemical mechanism for STAT3/β-catenin activation not reconstituted
    • Whether these axes depend on MISP's actin or MST1/2 activities unclear

Open questions

Synthesis pass · forward-looking unresolved questions
  • It remains unresolved how MISP's actin-bundling, spindle-orientation, and MST1/2-inhibitory activities are coordinated within a single cell and whether they share or compete for the same regions of the protein.
  • No structure of MISP or its interaction interfaces
  • No unified model integrating cytoskeletal and Hippo-signaling roles
  • Tissue-specific dominance of each function undefined

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0008092 cytoskeletal protein binding 4 GO:0098772 molecular function regulator activity 3 GO:0060090 molecular adaptor activity 2 GO:0140096 catalytic activity, acting on a protein 1
Localization
GO:0005856 cytoskeleton 3 GO:0005886 plasma membrane 3 GO:0005829 cytosol 1
Pathway
R-HSA-1640170 Cell Cycle 4 R-HSA-1643685 Disease 4 R-HSA-162582 Signal Transduction 2

Evidence

Reading pass · 15 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2013 MISP (C19orf21) is a substrate of Plk1; Plk1 phosphorylates MISP, and this phosphorylation is required for the metaphase-to-anaphase transition and proper mitotic spindle positioning. MISP is an actin-associated protein that forms a complex with p150(glued) (a dynein-dynactin subunit) and regulates its cortical distribution, thereby stabilizing cortical and astral microtubule attachments. Loss-of-function (siRNA depletion), phosphorylation assays identifying Plk1 as the kinase, co-immunoprecipitation of MISP with p150(glued), live-cell imaging of spindle orientation and astral microtubule length The Journal of cell biology High 23509069
2013 MISP associates with the actin cytoskeleton and focal adhesions and is expressed only in adherent cell types. During mitosis, MISP is phosphorylated by Cdk1 and localizes to retraction fibers. MISP interacts with the +TIP protein EB1 and with p150(glued) (dynein/dynactin). Depletion of MISP causes mitotic arrest with reduced tension across sister kinetochores, chromosome misalignment, spindle multipolarity (in cells with supernumerary centrosomes), and randomized spindle orientation. Co-immunoprecipitation (MISP with EB1 and p150glued), Cdk1 phosphorylation assay, siRNA depletion with live-cell imaging, immunofluorescence of focal adhesions and retraction fibers, kinetochore tension measurements Cell cycle (Georgetown, Tex.) High 23574715
2014 MISP/Caprice is a direct actin-binding protein with multiple actin-binding sites that forms mesh-like F-actin bundles in vitro. Overexpression induces stress fiber-like thick filaments and knockdown causes filopodial formation, demonstrating a direct role in actin cytoskeletal organization. It is expressed in cells/tissues with specialized actin structures such as growth cones and inner ear hair cell stereocilia. In vitro F-actin bundling assay with purified protein, overexpression and knockdown in cultured cells with morphological readout, fractionation identifying MISP in highly insoluble scaffold fraction Genes to cells : devoted to molecular & cellular mechanisms High 24475924
2018 MISP functions downstream of the ERM family member ezrin and upstream of NuMA in the spindle orientation pathway. SLK/LOK-activated (phosphorylated) ezrin competes with MISP for actin-binding sites at the cell cortex, limiting cortical MISP levels. Excessive MISP accumulation disrupts crescent-like NuMA polarization at the cortex and reduces astral microtubule dynamics. MISP directly interacts with ezrin. Co-immunoprecipitation (MISP–ezrin interaction), siRNA epistasis experiments (SLK/LOK, ezrin, MISP), live-cell imaging of NuMA localization and astral microtubule dynamics, cortical fractionation Journal of cell science High 29669740
2018 MISP interacts with the scaffolding protein IQGAP1, and through IQGAP1 binds the active (GTP-bound) form of Cdc42. MISP depletion increases IQGAP1 cortical accumulation and decreases Cdc42 activity. IQGAP1 overexpression rescues MISP-depletion phenotypes (spindle misorientation, loss of astral microtubules, prolonged mitosis) and restores active Cdc42 levels, placing IQGAP1 downstream of MISP. IQGAP1 also acts downstream of MISP in controlling p150(glued) localization. Co-immunoprecipitation (MISP–IQGAP1, IQGAP1–Cdc42), siRNA depletion epistasis, active-Cdc42 pull-down assay, IQGAP1 overexpression rescue experiments, immunofluorescence of p150(glued) localization Scientific reports High 29679050
2021 Phosphorylation of MISP at S394, S395, and S400 increases actin-bundling activity (but not actin-binding activity), inducing stress fiber formation in interphase cells. Mitotic phosphorylation at S376, S471, and S541 suppresses actin-binding activity. Thus, cell-cycle-dependent phosphorylation differentially regulates MISP actin-binding versus bundling activities. Site-directed mutagenesis of phosphorylation sites, in vitro actin-binding and bundling assays, overexpression of phosphomutants in cells with morphological readout Biochemical and biophysical research communications High 34023777
2022 MISP localizes specifically to the rootlet end (basal, pointed-end side) of microvillar actin core bundles in transporting epithelia. Purified MISP exhibits potent F-actin bundling activity in vitro and promotes rootlet elongation in cells. MISP-bundled filaments recruit fimbrin, which further elongates and stabilizes bundles. Ezrin prevents MISP from decorating the membrane-wrapped distal end of the core bundle, confining MISP to the rootlet. Immunofluorescence/live imaging for localization, in vitro actin bundling assay with purified protein, siRNA/CRISPR KO with microvillar phenotype readout (rootlet length), co-sedimentation assays, ezrin loss-of-function experiments Cell reports High 35443169
2023 MISP downregulation by M2 macrophage-derived extracellular vesicles promotes IQGAP1 nuclear translocation and activates STAT3 phosphorylation in hepatocellular carcinoma cells, leading to upregulation of PD-L1 and immune escape. MISP, IQGAP1, and STAT3 interact in a complex as shown by co-immunoprecipitation. MISP negatively correlates with IQGAP1/PD-L1 expression. Co-immunoprecipitation (MISP–IQGAP1–STAT3 complex), MISP/IQGAP1 overexpression experiments, flow cytometry of CD8+ T cells, ELISA for cytokines, in vivo nude mouse xenograft International immunopharmacology Medium 37633233
2023 In intrahepatic cholangiocarcinoma cells, MISP localizes to adherens junctions and suppresses E-cadherin dimerization. PLK1 phosphorylates MISP (confirmed as a PLK1 substrate in this context) and, together with MISP, disrupts adherens junctions to promote lymphatic invasion and cell motility. siRNA knockdown of PLK1 or MISP with trans-lymphatic endothelial migration and wound healing assays, immunofluorescence of focal adhesions and adherens junctions, in vivo tumorigenesis assay Cancer gene therapy Medium 38057358
2024 MISP directly binds the SARAH domain of MST1/2 kinases, inhibiting their homodimerization and autophosphorylation, thereby sustaining YAP activation (Hippo pathway inhibition). YAP activation in turn increases SLC7A11 expression to protect cells from ferroptosis. A MISP-R390/391A mutant that disrupts MISP–MST1/2 binding abolishes this effect. YAP also transcriptionally activates MISP, creating a positive feedback loop. Co-immunoprecipitation (MISP–MST1/2), site-directed mutagenesis (R390/391A), in vitro kinase/autophosphorylation assay, siRNA knockdown with ferroptosis sensitivity readout, Western blot for Hippo pathway components, in vivo xenograft Advanced science (Weinheim, Baden-Wurttemberg, Germany) High 40019375
2024 MISP preferentially binds ADP-actin (aged/pointed-end-enriched) filaments over ADP-Pi-actin filaments, and in vitro TIRF assays show MISP binds at or near the pointed ends of growing actin filaments. In solution, MISP assembles parallel bundles of uniform polarity, whereas substrate-attached MISP can bundle filaments in both parallel and antiparallel configurations. Microvillar rootlets are decorated with cofilin (indicating high ADP-actin content), consistent with MISP's nucleotide-state preference driving its rootlet localization. In vitro TIRF microscopy with purified MISP and differentially nucleotide-loaded actin filaments, immunostaining of native intestinal tissue for cofilin, in vitro bundling assays in solution vs. substrate-attached conditions The Journal of biological chemistry High 37205433 38588808
2024 MISP promotes nuclear accumulation of β-catenin, thereby activating the Wnt/β-catenin signaling pathway in pancreatic cancer cells. Fisetin suppresses MISP expression by downregulating the transcription factor MYB, identifying MYB as a transcriptional activator of MISP. Overexpression/knockdown of MISP with Western blot for β-catenin nuclear localization, in vitro proliferation assays, in vivo xenograft, drug screening library Biochimica et biophysica acta. Molecular basis of disease Medium 39278512
2024 MISP forms a complex with Opa Interacting Protein 5 (OIP5) in the cytoplasm, and MISP influences OIP5 expression in a unidirectional manner. MISP also increases phosphorylated STAT3 levels via the JAK2-STAT3 signaling pathway in colorectal cancer cells. Co-immunoprecipitation (MISP–OIP5 complex), Western blot for pSTAT3, MISP-deficient mouse model (AOM/DSS colitis-induced tumors), siRNA knockdown with cell proliferation readout International journal of molecular sciences Medium 38474305
2025 MISP directly interacts with MST1 (co-immunoprecipitation confirmed), inhibiting Hippo signaling and leading to increased YAP, TAZ, and CYR61 expression and decreased MST1 and phospho-YAP levels in lung adenocarcinoma cells. Co-immunoprecipitation (MISP–MST1), Western blot for Hippo pathway components, overexpression/knockdown with in vitro and in vivo proliferation and migration assays Discover oncology Medium 41249743
2022 MISP-deficient mice show exacerbated DSS-induced colitis, with decreased intestinal epithelial cell proliferation and significantly reduced Tgfb1 (TGF-β1) anti-inflammatory cytokine expression in the colon, indicating MISP supports colon recovery from inflammation partly through TGF-β1 signaling. MISP-knockout mouse model (DSS colitis), RT-qPCR for Tgfb1 and other cytokines, histological assessment of crypt morphology, Ki67 proliferation staining The Journal of veterinary medical science Medium 36596561

Source papers

Stage 0 corpus · 23 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2013 MISP is a novel Plk1 substrate required for proper spindle orientation and mitotic progression. The Journal of cell biology 63 23509069
2013 The novel actin/focal adhesion-associated protein MISP is involved in mitotic spindle positioning in human cells. Cell cycle (Georgetown, Tex.) 41 23574715
2023 Mechanism of M2 type macrophage-derived extracellular vesicles regulating PD-L1 expression via the MISP/IQGAP1 axis in hepatocellular carcinoma immunotherapy resistance. International immunopharmacology 31 37633233
2017 Duplication and concerted evolution of MiSp-encoding genes underlie the material properties of minor ampullate silks of cobweb weaving spiders. BMC evolutionary biology 31 28288560
2022 Mitotic Spindle Positioning (MISP) is an actin bundler that selectively stabilizes the rootlets of epithelial microvilli. Cell reports 22 35443169
2018 Activated ezrin controls MISP levels to ensure correct NuMA polarization and spindle orientation. Journal of cell science 22 29669740
2018 MISP regulates the IQGAP1/Cdc42 complex to collectively orchestrate spindle orientation and mitotic progression. Scientific reports 17 29679050
2014 Caprice/MISP is a novel F-actin bundling protein critical for actin-based cytoskeletal reorganizations. Genes to cells : devoted to molecular & cellular mechanisms 15 24475924
2025 MISP Suppresses Ferroptosis via MST1/2 Kinases to Facilitate YAP Activation in Non-Small Cell Lung Cancer. Advanced science (Weinheim, Baden-Wurttemberg, Germany) 14 40019375
2015 CAPRICE family genes control flowering time through both promoting and repressing CONSTANS and FLOWERING LOCUS T expression. Plant science : an international journal of experimental plant biology 13 26706076
2023 Characteristic Evaluation of Recombinant MiSp/Poly(lactic-co-glycolic) Acid (PLGA) Nanofiber Scaffolds as Potential Scaffolds for Bone Tissue Engineering. International journal of molecular sciences 8 36674734
2024 MISP-mediated enhancement of pancreatic cancer growth through the Wnt/β-catenin signaling pathway is suppressed by Fisetin. Biochimica et biophysica acta. Molecular basis of disease 7 39278512
2023 PLK1 and its substrate MISP facilitate intrahepatic cholangiocarcinoma progression by promoting lymphatic invasion and impairing E-cadherin adherens junctions. Cancer gene therapy 7 38057358
2024 Mitotic Spindle Positioning (MISP) Facilitates Colorectal Cancer Progression by Forming a Complex with Opa Interacting Protein 5 (OIP5) and Activating the JAK2-STAT3 Signaling Pathway. International journal of molecular sciences 6 38474305
2022 Mitotic spindle positioning protein (MISP) deficiency exacerbates dextran sulfate sodium (DSS)-induced colitis in mice. The Journal of veterinary medical science 6 36596561
2024 MISP Is Overexpressed in Intestinal Metaplasia and Gastric Cancer. Current oncology (Toronto, Ont.) 5 38785491
2015 Overexpressing CAPRICE and GLABRA3 did not change the anthocyanin content of tomato (Solanum lycopersicum) fruit peel. Plant signaling & behavior 5 26039466
2023 The Trypanosoma brucei MISP family of invariant proteins is co-expressed with BARP as triple helical bundle structures on the surface of salivary gland forms, but is dispensable for parasite development within the tsetse vector. PLoS pathogens 4 36996244
2025 The predictive value of MISP for the postoperative outcomes of gastric cancer. Biomedical research (Tokyo, Japan) 1 40436766
2024 Mitotic spindle positioning protein (MISP) preferentially binds to aged F-actin. The Journal of biological chemistry 1 38588808
2021 Modulation of actin-binding and -bundling activities of MISP/Caprice by multiple phosphorylation. Biochemical and biophysical research communications 1 34023777
2025 MISP promotes the progression of lung adenocarcinoma through Inhibition of the Hippo signaling pathway. Discover oncology 0 41249743
2023 Mitotic spindle positioning protein (MISP) is an actin bundler that senses ADP-actin and binds near the pointed ends of filaments. bioRxiv : the preprint server for biology 0 37205433

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