Affinage

MASP1

Mannan-binding lectin serine protease 1 · UniProt P48740

Length
699 aa
Mass
79.2 kDa
Annotated
2026-04-28
100 papers in source corpus 32 papers cited in narrative 32 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

MASP1 encodes a multifunctional serine protease central to the complement lectin pathway, coagulation, endothelial inflammation, and developmental patterning; alternative splicing of the same gene produces MASP-1, MASP-3, and the regulatory inhibitor MAp44. MASP-1 rapidly autoactivates (~3000-fold faster than MASP-2) and serves as the exclusive physiological activator of MASP-2 within MBL/ficolin/collectin-11 co-complexes, also directly cleaving C2 to contribute approximately 60% of C3 convertase formation (PMID:22691502, PMID:23386610, PMID:23785123). Beyond complement, MASP-1 exhibits thrombin-like activity—cleaving prothrombin, factor XIII, fibrinogen, and TAFI to promote coagulation, releasing bradykinin from high-molecular-weight kininogen, and activating endothelial cells via PAR4 (and PAR1) cleavage to trigger NF-κB/p38 MAPK signaling, cytokine secretion, neutrophil recruitment, E-selectin upregulation, and increased vascular permeability (PMID:22536427, PMID:21625439, PMID:19667088, PMID:31130964). Mutations in MASP1 cause 3MC syndrome, a developmental disorder involving craniofacial abnormalities linked to disrupted neural crest cell migration guidance through the MASP-1/collectin-11 axis (PMID:21258343).

Mechanistic history

Synthesis pass · year-by-year structured walk · 12 steps
  1. 1999 High

    Establishing that the MBL-associated complex contains multiple alternatively generated components—including sMAP (truncated MASP-2)—that co-associate with MASP-1, revealing the compositional complexity of the lectin pathway initiation complex.

    Evidence cDNA sequencing and co-purification from serum MBL complexes

    PMID:10330290

    Open questions at the time
    • Stoichiometry of MASP-1/sMAP within MBL complexes undefined
    • Functional consequence of sMAP association with MASP-1 unclear
  2. 2001 High

    Discovery that the MASP1 gene generates MASP-3 by alternative splicing, and that MASP-3 associates with distinct (larger) MBL oligomers and downregulates MASP-2-mediated C4/C2 cleavage, revealing an intrinsic regulatory circuit encoded by the same gene.

    Evidence Alternative splicing analysis, MBL oligomer fractionation, and complement activation assays

    PMID:11485744

    Open questions at the time
    • Physiological concentration and regulation of MASP-3 not determined
    • Mechanism of MASP-3 inhibition of MASP-2 activity not resolved
  3. 2004 High

    Defining MASP-1's substrate specificity as thrombin-like (preferring Phe-Gly-Arg), with inhibition by C1-inhibitor, established a biochemical basis for its dual complement/coagulation function.

    Evidence Fluorescent amide substrate profiling and inhibitor panel with recombinant and serum-derived MASP-1

    PMID:14725788

    Open questions at the time
    • Natural macromolecular substrates beyond complement components not yet mapped
    • In vivo relevance of thrombin-like activity not demonstrated
  4. 2006 High

    Demonstrating that MASP-1 synergizes with MASP-2 for C3 convertase generation via C2 and C4 (but not factor B) established MASP-1 as a necessary amplifier rather than a redundant enzyme in the lectin pathway.

    Evidence MASP-depleted serum reconstitution with recombinant MASP-1 and MASP-2, C3b deposition on mannan

    PMID:17182967

    Open questions at the time
    • Relative quantitative contribution of MASP-1 vs MASP-2 to C2 cleavage not measured
    • Mechanism of synergy (sequential or simultaneous) not resolved
  5. 2008 High

    Two independent lines of evidence—MASP1/3-knockout mice with impaired C4/C3 deposition rescued by recombinant MASP-1, and biochemical mapping of MASP-1 cleavage of factor XIII and fibrinogen at thrombin-identical sites—established MASP-1 as essential for both lectin pathway complement activation and cross-talk with coagulation.

    Evidence MASP1/3-KO mouse reconstitution (lectin pathway); in vitro cleavage with N-terminal sequencing (coagulation substrates)

    PMID:18424734 PMID:18456010

    Open questions at the time
    • MASP-1 contribution to hemostasis in vivo not tested
    • MASP-3 loss confounds interpretation of KO mouse complement phenotype
  6. 2009 High

    Discovery that MASP-1 activates endothelial cells through proteolytic cleavage of PAR4, triggering Ca²⁺/NF-κB/p38 MAPK signaling, and that MAp44 (a third splice product of MASP1) competitively inhibits lectin pathway activation, revealed MASP-1's pro-inflammatory endothelial role and a built-in negative regulator.

    Evidence PAR4 agonist peptide controls, PAR4 surface depletion assay on HUVECs; SPR/ELISA/complement assays for MAp44

    PMID:19667088 PMID:19917686

    Open questions at the time
    • PAR4 cleavage site on MASP-1 not mapped at residue level
    • In vivo relevance of MAp44 regulation not established
  7. 2011 High

    Identification of MASP1 mutations as the cause of 3MC syndrome, with zebrafish morphants recapitulating craniofacial defects and CL-K1 serving as a neural crest guidance cue, linked the MASP1 gene to developmental biology beyond innate immunity; separately, MASP-1 was shown to release bradykinin from HK, connecting it to the kinin system.

    Evidence Homozygosity mapping/exome sequencing in 3MC families, zebrafish morpholino knockdown; in vitro HK cleavage with HPLC bradykinin detection

    PMID:21258343 PMID:21625439

    Open questions at the time
    • Which MASP1 splice product (MASP-1 vs MASP-3) mediates neural crest guidance not resolved
    • Bradykinin release by MASP-1 not confirmed in vivo
  8. 2012 High

    Convergent genetic and biochemical evidence—a MASP-1/3-deficient patient confirming MASP-1 as essential for lectin pathway activation, monospecific inhibitors proving MASP-1 is the exclusive MASP-2 activator contributing ~60% of C2 cleavage, and demonstration of MASP-1/MASP-2 co-complexes on MBL—solidified the mechanistic hierarchy of lectin pathway initiation.

    Evidence Human nonsense mutation reconstitution; monospecific inhibitors in normal serum; co-complex demonstration by native PAGE/SEC; crystal structures of MASP-1/MASP-2 Michaelis complexes

    PMID:22511776 PMID:22691502 PMID:22966085 PMID:23785123

    Open questions at the time
    • Structure of the full MBL–MASP-1–MASP-2 ternary complex not solved
    • Mechanism of autoactivation signal initiation on pattern recognition molecules unknown
  9. 2013 High

    Crystal structure of proenzyme MASP-1 explained its ~3000-fold faster autoactivation relative to MASP-2 and showed that both zymogen and activated MASP-1 cleave proenzyme MASP-2 and MASP-3, providing the structural basis for the activation cascade hierarchy.

    Evidence 2.5 Å crystal structure of proenzyme MASP-1, autoactivation kinetics with R448Q/S646A mutants

    PMID:23386610

    Open questions at the time
    • How pattern recognition molecule binding triggers initial autoactivation event not structurally resolved
    • Rate of MASP-1-to-MASP-3 activation in vivo not determined
  10. 2015 High

    Detailed mapping of prothrombin activation by MASP-1 revealed two simultaneous cleavage pathways (R271-first and R393-first, both requiring R320), generating alternative active thrombin species, distinguishing MASP-1's coagulation mechanism from canonical thrombin generation.

    Evidence Arginine-to-glutamine prothrombin mutants, SDS-PAGE, N-terminal sequencing, thrombelastography

    PMID:25745807 PMID:26645987

    Open questions at the time
    • Biological significance of alternative thrombin species not characterized
    • Whether MASP-1-generated thrombin has altered substrate preferences unknown
  11. 2016 High

    MASP-3 was identified as the exclusive activator of pro-factor D in resting blood (not MASP-1 or MASP-2), delineating functional specialization among MASP1 gene products: MASP-1 drives lectin pathway initiation while MASP-3 primes the alternative pathway.

    Evidence Evolved monospecific inhibitors for MASP-1, -2, -3 tested in pro-factor D activation assays in resting blood

    PMID:27535802

    Open questions at the time
    • Whether MASP-1 can activate pro-factor D under inflammatory conditions not excluded
    • Regulatory mechanisms controlling MASP-3 activity in vivo unknown
  12. 2019 High

    MASP-1 was shown to increase endothelial permeability through PAR1-mediated Ca²⁺ mobilization and Rho-kinase/MLC phosphorylation, disrupting interendothelial junctions and upregulating bradykinin B2 receptor, revealing a second PAR substrate and a vascular leak mechanism.

    Evidence Real-time TEER measurement, XperT permeability assay, Ca²⁺ imaging, MLC phosphorylation, microarray on HUVECs

    PMID:31130964

    Open questions at the time
    • Relative contribution of PAR1 vs PAR4 to MASP-1-driven endothelial responses not quantified
    • In vivo vascular permeability change by MASP-1 not demonstrated

Open questions

Synthesis pass · forward-looking unresolved questions
  • Key unresolved questions include: the structural basis of the full MBL/ficolin–MASP ternary complex; how pattern recognition molecule engagement triggers MASP-1 autoactivation; the in vivo significance of MASP-1's coagulation and kinin-generating activities; and which MASP1 splice product mediates the developmental functions disrupted in 3MC syndrome.
  • Full ternary complex structure of lectin–MASP assemblies unsolved
  • In vivo contribution of MASP-1 to hemostasis vs complement not genetically dissected
  • Molecular mechanism linking MASP1 products to neural crest migration guidance uncharacterized

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0140096 catalytic activity, acting on a protein 10 GO:0016787 hydrolase activity 3 GO:0098772 molecular function regulator activity 3
Localization
GO:0005576 extracellular region 6 GO:0031410 cytoplasmic vesicle 1
Pathway
R-HSA-168256 Immune System 6 R-HSA-109582 Hemostasis 5 R-HSA-162582 Signal Transduction 3 R-HSA-1266738 Developmental Biology 1
Partners
COLEC11F13A1F2FCN1FGBMASP2MBL2SERPING1
Complex memberships
CL-K1-MASP complexFicolin-MASP complexMBL-MASP complex

Evidence

Reading pass · 32 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2001 MASP-3 is generated through alternative splicing of the MASP-1/3 gene and associates with distinct MBL oligomers; larger MBL oligomers carry MASP-3 and MASP-2, while smaller oligomers carry MASP-1 and MAp19. MASP-3 downregulates C4 and C2 cleaving activity of MASP-2. Alternative splicing analysis, oligomer fractionation, functional complement activation assays Immunity High 11485744
1999 The MBL-MASP complex contains a 22 kDa protein (sMAP) that is a truncated form of MASP-2 generated by alternative polyadenylation, and sMAP associates with MASP-1 within the MBL complex. cDNA sequencing, protein biochemistry, Co-purification/Co-IP International immunology High 10330290
2009 MAp44, an alternatively spliced product of the MASP1 gene sharing the first four domains with MASP-1 and MASP-3 plus 17 unique C-terminal residues, is found in serum at ~1.4 µg/ml and competes with MASP-2 for binding to MBL and ficolins, thereby inhibiting complement activation. Surface plasmon resonance (SPR), ELISA, complement activation assays, mRNA profiling Journal of immunology High 19917686
2012 In normal human serum, MASP-1 is the exclusive activator of MASP-2; MASP-2 cannot autoactivate under physiological conditions, and inhibition of MASP-1 prevents MASP-2 activation. MASP-1 also contributes ~60% of C2a generation for C3 convertase formation. Monospecific inhibitors against MASP-1 and MASP-2, complement activation assays in normal human serum PNAS High 22691502
2008 MASP-1 contributes to lectin pathway activation by promoting MASP-2 activation; MASP1/3-deficient mouse serum shows significantly lower C4 and C3 deposition on mannan, and activity is restored by adding recombinant MASP-1, which accelerates MASP-2 activation. Gene-targeted MASP1/3-knockout mice, C4/C3 deposition assays, reconstitution with recombinant MASP-1 Journal of immunology High 18424734
2004 MASP-1 has thrombin-like substrate specificity, cleaving Phe-Gly-Arg-AMC most rapidly among tested fluorescent amide substrates; MASP-1 is inhibited by C1 inhibitor and the thrombin inhibitor boroMpg (but not hirudin), whereas MASP-2 shows minimal amidolytic activity toward the same substrates. Fluorescent amide substrate cleavage assays with recombinant and serum-derived MASPs, inhibitor profiling Molecular immunology High 14725788
2009 MASP-1 activates Ca2+ signaling, NF-κB, and p38 MAPK pathways in cultured HUVECs through proteolytic cleavage of PAR4; MASP-2 had no such effect, and the proteolytic activity of MASP-1 is required for endothelial activation. Cell-based signaling assays, synthetic PAR peptide substrates, PAR4 agonist peptide, mRNA quantification, membrane PAR4 depletion assay Journal of immunology High 19667088
2012 MASP-1 activates factor XIII and cleaves fibrinogen and prothrombin in plasma-based systems; MASP-1 directly activates prothrombin and TAFI, and induces fibrin clot formation with altered clot structure. FXIII incorporation assay, specific activation product assays (F1+2, FPA, TAFIa), turbidimetric clotting assay, scanning electron microscopy PloS one High 22536427
2008 MASP-1 cleaves factor XIII A-chain and fibrinogen beta-chain at sites identical to thrombin, releases fibrinopeptide B (but not A), and drives cross-linked fibrinogen formation; thrombin turnover rate for factor XIII is ~650-fold faster than MASP-1. In vitro cleavage assays with recombinant MASP-1 and thrombin, SDS-PAGE, N-terminal sequencing Biochimica et biophysica acta High 18456010
2011 MASP-1 cleaves high-molecular-weight kininogen (HK) to release bradykinin; MASP-2 can also cleave HK but cannot release bradykinin. C1-inhibitor prevents HK cleavage by both MASPs. Differential gel electrophoresis (proteomic screen), SDS-PAGE, HPLC detection of bradykinin release PloS one High 21625439
2012 MASP-1 is essential for lectin pathway activation in a MASP-1/3-deficient patient; the alternative pathway functions normally in this patient and is unaffected by MASP-1/MASP-3 reconstitution. MASP-1 and MASP-2 can form co-complexes on MBL in serum, providing a structural basis for MASP-1-mediated transactivation of MASP-2. Patient with nonsense mutation in MASP1 gene, complement functional assays, reconstitution with recombinant MASPs, demonstration of MASP-1/MASP-2 co-complexes in serum Journal of immunology High 22966085
2016 MASP-3 is the exclusive activator of pro-factor D in resting blood; neither MASP-1 nor MASP-2 activates pro-factor D under resting physiological conditions, as demonstrated using specific evolved inhibitors against all three MASPs. Evolved monospecific MASP-1, MASP-2, and MASP-3 inhibitors, pro-factor D activation assays in resting blood Scientific reports High 27535802
2013 Zymogen MASP-1 autoactivates ~3000-fold faster than zymogen MASP-2; both activated and proenzyme MASP-1 efficiently cleave proenzyme MASP-2, and MASP-1 also cleaves proenzyme MASP-3. Crystal structure of proenzyme MASP-1 at 2.5 Å explains the unusual activity of the zymogen. In vitro autoactivation kinetics with recombinant MASP-1/MASP-2 mutants (R448Q, S646A), crystal structure at 2.5 Å, synthetic substrate cleavage assays Journal of biological chemistry High 23386610
2012 Both MASP-1 and MASP-2 are essential for lectin pathway activation; crystal structures of Michaelis-like complexes of MASP-1 and MASP-2 with substrate-like inhibitors at 1.28 Å resolution reveal plasticity of MASP-2 and explain enzyme-substrate interactions. Evolved monospecific inhibitors, lectin pathway functional assays, crystal structure determination (1.28 Å for MASP-2) Journal of biological chemistry High 22511776
2015 MASP-1 promotes clotting by directly activating prothrombin at three cleavage sites (R155, R271, R393), producing an alternative active thrombin species; MASP-1-induced clotting in whole blood and platelet-poor plasma is dependent on prothrombin. Thrombelastography, SDS-PAGE, N-terminal sequencing of cleavage products, prothrombin-depleted plasma Molecular immunology High 25745807
2015 MASP-1 activates prothrombin via two simultaneous pathways (cleaving R271 or R393 first), both requiring R320 cleavage and resulting in formation of active alternative thrombin species; R155 is not an important cleavage site for prothrombin activation. Arginine-to-glutamine prothrombin mutants (R271Q, R320Q, R393Q), active-site mutant S525A, SDS-PAGE, N-terminal sequencing, thrombelastography PloS one High 26645987
2010 Collectin-11 (CL-K1) associates with MASP-1 and/or MASP-3 in plasma as demonstrated by co-purification and ELISA; CL-K1 also binds bacteria, fungi, and viruses. ELISA, co-purification, Western blotting, mass spectrometry Journal of immunology High 20956340
2012 Collectin-11 associates with MASP-1, MASP-2, MASP-3, and MAP-1, and CL-11/MASP-2 complexes mediate C4b deposition on Candida albicans, defining CL-11 as the fifth lectin pathway recognition molecule. Protein interaction assays, C4b/C3b deposition assays on Candida albicans, depletion and reconstitution experiments Journal of innate immunity High 23220946
2014 MASP-1 induces IL-6 and IL-8 secretion (but not IL-1α, IL-1ra, TNFα, or MCP-1) from HUVECs through the p38 MAPK pathway, and conditioned supernatant activates neutrophil chemotaxis. Recombinant MASP-1 stimulation of HUVECs, cytokine ELISA, p38 MAPK pathway inhibition, neutrophil chemotaxis assay PloS one High 24489848
2014 Serum MASP-1 in complex with MBL activates endothelial cells through the proteolytic activity of MASP-1; MASP-2, MASP-3, and non-enzymatic N-terminal domains of MASP-1/MASP-2 do not activate HUVECs, and a stable zymogen MASP-1 mutant is also inactive. Ca2+ signaling in HUVECs stimulated with MBL-MASP complexes, recombinant MASP fragments, zymogen MASP-1 mutant Molecular immunology High 24472859
2013 MASP-1 and MASP-2 form co-complexes on MBL and ficolins (despite not forming heterodimers directly); these co-complexes are present in serum and are functionally active in complement activation. MAp44 disrupts co-complexes, impairing MASP-2 transactivation. Native PAGE, size exclusion chromatography, functional complement assays, MBL/ficolin-mediated co-complex formation experiments Journal of immunology High 23785123
2012 Crystal structure of MAP-1 (MAp44) reveals a head-to-tail homodimer (~146 Å long); MAP-1 forms a calcium-dependent homodimer in solution and competes with all three MASPs for binding to MBL and ficolins, inhibiting lectin pathway activation. Crystal structure determination, multi-angle laser light scattering, surface plasmon resonance, C3/C9 deposition inhibition assays Journal of biological chemistry High 22854970
2014 MASP-1 CUB1-EGF-CUB2 (D1-3) domains form tight Ca2+-dependent homodimers; MASP-1 and MASP-2 D1-3 domains can form heterodimers after dissociation-reassociation, and MASP-1:MASP-3 heterodimers readily exchange subunits even in the presence of Ca2+. Size exclusion chromatography, native PAGE, EDTA dissociation/recalcification reassociation experiments Molecular immunology Medium 24424083
2019 MASP-1 directly increases endothelial permeability through PAR1-mediated Ca2+ mobilization, Rho-kinase-dependent MLC phosphorylation, cytoskeletal actin rearrangement, and disruption of interendothelial junctions; MASP-1 also up-regulates bradykinin B2 receptor expression in HUVECs. Real-time micro electric sensing (TEER), XperT permeability assay, Ca2+ imaging, MLC phosphorylation assay, microarray transcriptome analysis Frontiers in immunology High 31130964
2016 MASP-1 increases E-selectin expression on HUVECs (while decreasing ICAM-2), enhancing adhesion between endothelial cells and differentiated PLB-985 neutrophil model cells. Flow cytometry for adhesion molecule expression, cell adhesion assay with differentiated PLB-985 cells Molecular immunology Medium 27219453
2018 MASP-1 enhances fibrin clot formation in a microvascular whole blood flow model; addition of selective MASP-1 inhibitor SGMI-1 delays clot formation, and complement activation by zymosan increases clotting in a MASP-1-dependent manner. Microfluidic endothelialized microchannel system, confocal microscopy real-time clot imaging, selective MASP-1 inhibitor SGMI-1 PloS one High 29324883
2011 Mutations in MASP1 cause 3MC syndrome; zebrafish morphants for MASP1 develop craniofacial abnormalities, and CL-K1 (encoded by COLEC11, a binding partner of MASP-1) serves as a guidance cue for neural crest cell migration. Homozygosity mapping, whole exome sequencing, Sanger sequencing, zebrafish morpholino knockdown Nature genetics High 21258343
2022 MASP-1-enriched small extracellular vesicles (EVs) released from hepatocytes activate hepatic stellate cells (HSCs) via p38 MAPK/ATF2 signaling to promote liver fibrosis; ARRB1 upregulates MASP1 expression in hepatocytes and increases EV release via Rab27A. Small EV purification, proteomic analysis, primary hepatocyte/HSC co-culture, p38 MAPK inhibition, CCl4 mouse model, siRNA knockdown Hepatology Medium 35849032
2006 MASP-1 cooperates with MASP-2 in C3 convertase generation via the MBL pathway; synergistic reconstitution with both MASP-1 and MASP-2 in MASP-depleted serum restores C3b deposition, dependent on C2 and C4 but not factor B. MASP-depleted serum reconstitution, C3b deposition assays, component-depleted sera International immunology High 17182967
2002 MASP-1/3 promoter is liver-specific and slightly upregulated by IL-1β; MASP-1/3 promoter activity is downregulated by IFN-γ and the stimulatory effect of IL-1β is abolished by IL-6—contrasting with C1s promoter which is strongly upregulated by IL-6. Reporter gene (luciferase) assays with 5'-flanking MASP-1/3 and MASP-2 gene constructs, cytokine stimulation International immunology Medium 12356684
2020 CRP binds monosodium urate (MSU) crystals and recruits complement proteases C1 and MASP-1 to the crystal surface, linking pattern recognition to complement activation at MSU crystals. Protein purification from human body fluids, CRP depletion from serum, complement fixation assays Scientific reports Medium 32286427
2022 MASP-1/C1-INH complex levels are increased in serum during zymosan-induced complement activation and are elevated in COVID-19 patients, validating MASP-1/C1-INH complexes as markers of early lectin pathway activation; C1 esterase inhibitor (C1-INH) forms covalent complexes with active MASP-1. Sandwich ELISA, zymosan activation, COVID-19 patient cohort Frontiers in immunology Medium 36420270

Source papers

Stage 0 corpus · 100 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2001 MASP-3 and its association with distinct complexes of the mannan-binding lectin complement activation pathway. Immunity 278 11485744
2011 Mutations in lectin complement pathway genes COLEC11 and MASP1 cause 3MC syndrome. Nature genetics 196 21258343
2008 Poly(ethylene glycol)s generate complement activation products in human serum through increased alternative pathway turnover and a MASP-2-dependent process. Molecular immunology 175 18849076
2010 Collectin 11 (CL-11, CL-K1) is a MASP-1/3-associated plasma collectin with microbial-binding activity. Journal of immunology (Baltimore, Md. : 1950) 170 20956340
2012 Revised mechanism of complement lectin-pathway activation revealing the role of serine protease MASP-1 as the exclusive activator of MASP-2. Proceedings of the National Academy of Sciences of the United States of America 163 22691502
1999 A truncated form of mannose-binding lectin-associated serine protease (MASP)-2 expressed by alternative polyadenylation is a component of the lectin complement pathway. International immunology 140 10330290
2009 MAp44, a human protein associated with pattern recognition molecules of the complement system and regulating the lectin pathway of complement activation. Journal of immunology (Baltimore, Md. : 1950) 136 19917686
2020 Safety, Tolerability and Efficacy of Narsoplimab, a Novel MASP-2 Inhibitor for the Treatment of IgA Nephropathy. Kidney international reports 127 33163724
2008 Mannose-binding lectin (MBL)-associated serine protease (MASP)-1 contributes to activation of the lectin complement pathway. Journal of immunology (Baltimore, Md. : 1950) 127 18424734
2000 MAP-1, a novel proapoptotic protein containing a BH3-like motif that associates with Bax through its Bcl-2 homology domains. The Journal of biological chemistry 118 11060313
2012 Mannan-binding lectin-associated serine protease (MASP)-1 is crucial for lectin pathway activation in human serum, whereas neither MASP-1 nor MASP-3 is required for alternative pathway function. Journal of immunology (Baltimore, Md. : 1950) 116 22966085
2004 Differential substrate and inhibitor profiles for human MASP-1 and MASP-2. Molecular immunology 113 14725788
2016 MASP-3 is the exclusive pro-factor D activator in resting blood: the lectin and the alternative complement pathways are fundamentally linked. Scientific reports 108 27535802
2009 Complement protease MASP-1 activates human endothelial cells: PAR4 activation is a link between complement and endothelial function. Journal of immunology (Baltimore, Md. : 1950) 108 19667088
2010 MASP1 mutations in patients with facial, umbilical, coccygeal, and auditory findings of Carnevale, Malpuech, OSA, and Michels syndromes. American journal of human genetics 103 21035106
2005 MAP-1 is a mitochondrial effector of Bax. Proceedings of the National Academy of Sciences of the United States of America 100 16199525
2022 Highly pathogenic coronavirus N protein aggravates inflammation by MASP-2-mediated lectin complement pathway overactivation. Signal transduction and targeted therapy 99 36100602
2012 Collectin-11/MASP complex formation triggers activation of the lectin complement pathway--the fifth lectin pathway initiation complex. Journal of innate immunity 96 23220946
2012 Effects of MASP-1 of the complement system on activation of coagulation factors and plasma clot formation. PloS one 95 22536427
1998 Two lineages of mannose-binding lectin-associated serine protease (MASP) in vertebrates. Journal of immunology (Baltimore, Md. : 1950) 95 9794427
2008 The action of MBL-associated serine protease 1 (MASP1) on factor XIII and fibrinogen. Biochimica et biophysica acta 92 18456010
2011 Cleavage of kininogen and subsequent bradykinin release by the complement component: mannose-binding lectin-associated serine protease (MASP)-1. PloS one 91 21625439
1985 Microtubule-associated proteins (MAPs): a monoclonal antibody to MAP 1 decorates microtubules in vitro but stains stress fibers and not microtubules in vivo. Proceedings of the National Academy of Sciences of the United States of America 82 3883359
2010 Biological variations of MASP-3 and MAp44, two splice products of the MASP1 gene involved in regulation of the complement system. Journal of immunological methods 81 20673767
2014 Multiple roles of complement MASP-1 at the interface of innate immune response and coagulation. Molecular immunology 80 24935208
2009 Multi-component complement system of Cnidaria: C3, Bf, and MASP genes expressed in the endodermal tissues of a sea anemone, Nematostella vectensis. Immunobiology 80 19195737
2022 Hepatocyte-derived MASP1-enriched small extracellular vesicles activate HSCs to promote liver fibrosis. Hepatology (Baltimore, Md.) 73 35849032
2006 Cooperation between MASP-1 and MASP-2 in the generation of C3 convertase through the MBL pathway. International immunology 73 17182967
2003 Origin of mannose-binding lectin-associated serine protease (MASP)-1 and MASP-3 involved in the lectin complement pathway traced back to the invertebrate, amphioxus. Journal of immunology (Baltimore, Md. : 1950) 71 12707349
2016 MASP1, THBS1, GPLD1 and ApoA-IV are novel biomarkers associated with prediabetes: the KORA F4 study. Diabetologia 69 27344311
2012 Monospecific inhibitors show that both mannan-binding lectin-associated serine protease-1 (MASP-1) and -2 Are essential for lectin pathway activation and reveal structural plasticity of MASP-2. The Journal of biological chemistry 69 22511776
2010 Selective inhibition of the lectin pathway of complement with phage display selected peptides against mannose-binding lectin-associated serine protease (MASP)-1 and -2: significant contribution of MASP-1 to lectin pathway activation. Journal of immunology (Baltimore, Md. : 1950) 64 20817870
2009 Identification of novel candidate target genes, including EPHB3, MASP1 and SST at 3q26.2-q29 in squamous cell carcinoma of the lung. BMC cancer 63 19607727
2004 The structure of MBL-associated serine protease-2 reveals that identical substrate specificities of C1s and MASP-2 are realized through different sets of enzyme-substrate interactions. Journal of molecular biology 62 15364579
2013 Quantitative characterization of the activation steps of mannan-binding lectin (MBL)-associated serine proteases (MASPs) points to the central role of MASP-1 in the initiation of the complement lectin pathway. The Journal of biological chemistry 58 23386610
2011 Sequence-structure correlations in silk: Poly-Ala repeat of N. clavipes MaSp1 is naturally optimized at a critical length scale. Journal of the mechanical behavior of biomedical materials 57 22340682
2007 Multiple recombining loci encode MaSp1, the primary constituent of dragline silk, in widow spiders (Latrodectus: Theridiidae). Molecular biology and evolution 52 18048404
2015 MASP-1 of the complement system promotes clotting via prothrombin activation. Molecular immunology 51 25745807
2013 Co-complexes of MASP-1 and MASP-2 associated with the soluble pattern-recognition molecules drive lectin pathway activation in a manner inhibitable by MAp44. Journal of immunology (Baltimore, Md. : 1950) 50 23785123
2017 Immune complexes in chronic Chagas disease patients are formed by exovesicles from Trypanosoma cruzi carrying the conserved MASP N-terminal region. Scientific reports 48 28294160
2016 Mannan binding lectin-associated serine protease-2 (MASP-2) critically contributes to post-ischemic brain injury independent of MASP-1. Journal of neuroinflammation 48 27577570
2006 The mannan-binding lectin pathway and lung disease in cystic fibrosis--disfunction of mannan-binding lectin-associated serine protease 2 (MASP-2) may be a major modifier. Clinical immunology (Orlando, Fla.) 48 17045845
2017 Analysis of Factor D Isoforms in Malpuech-Michels-Mingarelli-Carnevale Patients Highlights the Role of MASP-3 as a Maturase in the Alternative Pathway of Complement. Journal of immunology (Baltimore, Md. : 1950) 46 28794230
2003 Expression of H-ficolin/Hakata antigen, mannose-binding lectin-associated serine protease (MASP)-1 and MASP-3 by human glioma cell line T98G. International immunology 46 12502731
1985 Microheterogeneity of microtubule-associated proteins, MAP-1 and MAP-2, and differential phosphorylation of individual subcomponents. The Journal of biological chemistry 46 2985613
2014 Mannose-Binding Lectin (MBL) and MBL-associated serine protease-2 (MASP-2) in women with malignant and benign ovarian tumours. Cancer immunology, immunotherapy : CII 44 25038892
2015 MASP-1 and MASP-2 Do Not Activate Pro-Factor D in Resting Human Blood, whereas MASP-3 Is a Potential Activator: Kinetic Analysis Involving Specific MASP-1 and MASP-2 Inhibitors. Journal of immunology (Baltimore, Md. : 1950) 43 26673137
2014 MASP-1 induces a unique cytokine pattern in endothelial cells: a novel link between complement system and neutrophil granulocytes. PloS one 43 24489848
2019 Cutting Edge: Role of MASP-3 in the Physiological Activation of Factor D of the Alternative Complement Pathway. Journal of immunology (Baltimore, Md. : 1950) 40 31399515
2007 Role of MBL-associated serine protease (MASP) on activation of the lectin complement pathway. Advances in experimental medicine and biology 40 17892207
1998 MASP1 (MBL-associated serine protease 1). Immunobiology 38 9777417
2015 Novel MASP1 mutations are associated with an expanded phenotype in 3MC1 syndrome. Orphanet journal of rare diseases 37 26419238
2015 Plasma levels of mannan-binding lectin-associated serine proteases MASP-1 and MASP-2 are elevated in type 1 diabetes and correlate with glycaemic control. Clinical and experimental immunology 36 25533914
2019 MASP-1 Increases Endothelial Permeability. Frontiers in immunology 33 31130964
2014 Essential role for the lectin pathway in collagen antibody-induced arthritis revealed through use of adenovirus programming complement inhibitor MAp44 expression. Journal of immunology (Baltimore, Md. : 1950) 33 25070856
2014 TFPI inhibits lectin pathway of complement activation by direct interaction with MASP-2. European journal of immunology 33 25359215
2005 Functional characterization of complement proteases C1s/mannan-binding lectin-associated serine protease-2 (MASP-2) chimeras reveals the higher C4 recognition efficacy of the MASP-2 complement control protein modules. The Journal of biological chemistry 33 16227207
2014 Impact of passive smoking, cooking with solid fuel exposure, and MBL/MASP-2 gene polymorphism upon susceptibility to tuberculosis. International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases 32 25312983
2022 In-depth mapping of protein localizations in whole tissue by micro-scaffold assisted spatial proteomics (MASP). Nature communications 31 36517484
2015 Impact of MBL and MASP-2 gene polymorphism and its interaction on susceptibility to tuberculosis. BMC infectious diseases 31 25887173
2016 Complement MASP-1 enhances adhesion between endothelial cells and neutrophils by up-regulating E-selectin expression. Molecular immunology 30 27219453
2009 Modular architecture and evolution of the map-1 gene family in the root-knot nematode Meloidogyne incognita. Molecular genetics and genomics : MGG 30 19787376
2009 Degradation of methamidophos by Hyphomicrobium species MAP-1 and the biochemical degradation pathway. Biodegradation 30 19960233
2012 Crystal structure and functional characterization of the complement regulator mannose-binding lectin (MBL)/ficolin-associated protein-1 (MAP-1). The Journal of biological chemistry 29 22854970
2018 MASP-1 of the complement system enhances clot formation in a microvascular whole blood flow model. PloS one 27 29324883
2014 C3 dysregulation due to factor H deficiency is mannan-binding lectin-associated serine proteases (MASP)-1 and MASP-3 independent in vivo. Clinical and experimental immunology 27 24279761
2009 Mannan-binding lectin-associated serine protease-2 (MASP-2) in a large cohort of neonates and its clinical associations. Molecular immunology 27 19307021
1998 MASP-2, the C3 convertase generating protease of the MBLectin complement activating pathway. Immunobiology 27 9777418
2022 MASP-2 and MASP-3 inhibitors block complement activation, inflammation, and microvascular stasis in a murine model of vaso-occlusion in sickle cell disease. Translational research : the journal of laboratory and clinical medicine 25 35878790
2022 Distinction of early complement classical and lectin pathway activation via quantification of C1s/C1-INH and MASP-1/C1-INH complexes using novel ELISAs. Frontiers in immunology 25 36420270
2020 Association of Polymorphisms of MASP1/3, COLEC10, and COLEC11 Genes with 3MC Syndrome. International journal of molecular sciences 25 32751929
2014 Serum MASP-1 in complex with MBL activates endothelial cells. Molecular immunology 25 24472859
2011 Mannan-binding lectin (MBL) and MBL-associated serine protease 2 (MASP-2) genotypes in colorectal cancer. Scandinavian journal of immunology 23 21198752
2006 Assembly of C1 and the MBL- and ficolin-MASP complexes: structural insights. Immunobiology 23 17544813
2005 Heterogeneity of MBL-MASP complexes. Molecular immunology 23 16102832
2017 Pentraxin 3, ficolin-2 and lectin pathway associated serine protease MASP-3 as early predictors of myocardial infarction - the HUNT2 study. Scientific reports 22 28216633
2019 Herpes simplex encephalitis in adult patients with MASP-2 deficiency. PLoS pathogens 21 31869396
2019 Should MASP-2 Deficiency Be Considered a Primary Immunodeficiency? Relevance of the Lectin Pathway. Journal of clinical immunology 20 31828694
2013 The role of MASP-1/3 in complement activation. Advances in experimental medicine and biology 20 23402018
2013 Leprosy association with low MASP-2 levels generated by MASP2 haplotypes and polymorphisms flanking MAp19 exon 5. PloS one 20 23935922
2012 The map-1 gene family in root-knot nematodes, Meloidogyne spp.: a set of taxonomically restricted genes specific to clonal species. PloS one 20 22719916
2011 Multiple domains of MASP-2, an initiating complement protease, are required for interaction with its substrate C4. Molecular immunology 20 22071314
1995 Localization of the genes for the 100-kDa complement-activating components of Ra-reactive factor (CRARF and Crarf) to human 3q27-q28 and mouse 16B2-B3. Genomics 20 7759119
2021 Targeting the Complement Serine Protease MASP-2 as a Therapeutic Strategy for Coronavirus Infections. Viruses 19 33671334
2011 Multiplex sequence-specific polymerase chain reaction reveals new MASP2 haplotypes associated with MASP-2 and MAp19 serum levels. Human immunology 19 21683108
2007 Genetic influences on mannan-binding lectin (MBL) and mannan-binding lectin associated serine protease-2 (MASP-2) activity. Genetic epidemiology 19 17096357
2000 A novel truncated isoform of the mannose-binding lectin-associated serine protease (MASP) from the common carp (Cyprinus carpio). Immunogenetics 19 10752628
2019 Expression and functional characterization of a mannose-binding lectin-associated serine protease-1 (MASP-1) from Nile tilapia (Oreochromis niloticus) in host defense against bacterial infection. Fish & shellfish immunology 18 31096060
2017 Mannan-binding lectin-associated serine protease-1 (MASP-1) mediates immune responses against Aeromonas hydrophila in vitro and in vivo in grass carp. Fish & shellfish immunology 18 28479400
2015 MASP-1 Induced Clotting--The First Model of Prothrombin Activation by MASP-1. PloS one 18 26645987
2014 Dissociation and re-association studies on the interaction domains of mannan-binding lectin (MBL)-associated serine proteases, MASP-1 and MASP-2, provide evidence for heterodimer formation. Molecular immunology 18 24424083
2020 C-reactive protein (CRP) recognizes uric acid crystals and recruits proteases C1 and MASP1. Scientific reports 17 32286427
2019 Reduced Mannose-Binding Lectin-Associated Serine Protease (MASP)-1 is Associated with Disturbed Coagulation in Septic Shock. Thrombosis and haemostasis 17 30986866
2016 Experimentally-induced anti-myeloperoxidase vasculitis does not require properdin, MASP-2 or bone marrow-derived C5. The Journal of pathology 17 27235854
2005 Structure of model peptides based on Nephila clavipes dragline silk spidroin (MaSp1) studied by 13C cross polarization/magic angle spinning NMR. Biomacromolecules 17 16283749
2004 Phylogenetic placement of the spider genus Nephila (Araneae: Araneoidea) inferred from rRNA and MaSp1 gene sequences. Zoological science 17 15056930
2018 Cardioprotection by an anti-MASP-2 antibody in a murine model of myocardial infarction. Open heart 16 29344374
2017 Plasma levels of MASP-1, MASP-3 and MAp44 in patients with type 2 diabetes: influence of glycaemic control, body composition and polymorphisms in the MASP1 gene. Clinical and experimental immunology 16 28318015
2002 Functional characterization of human mannose-binding lectin-associated serine protease (MASP)-1/3 and MASP-2 promoters, and comparison with the C1s promoter. International immunology 16 12356684
2022 MicroRNA-122-5p regulates coagulation and inflammation through MASP1 and HO-1 genes. Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases 15 35293311