Affinage

GZMA

Granzyme A · UniProt P12544

Length
262 aa
Mass
29.0 kDa
Annotated
2026-06-10
17 papers in source corpus 10 papers cited in narrative 10 extracted findings
Cross-family judge vs UniProt: tie faithfulness: 5/5 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

GZMA is a homodimeric, trypsin-like serine protease stored in the granules of cytolytic T cells and NK cells that has emerged as a multifunctional effector acting largely through extracellular signaling on target cells (PMID:8288245, PMID:3495579). Its enzymatic activity shapes adaptive immune output, biasing IL-12-stimulated responses toward a Th1 cytokine profile, since pharmacological inhibition of its serine protease activity shifts the response toward Th2 (PMID:24840346). A recurrent mechanistic theme is engagement of the protease-activated receptor F2R/PAR1 on target cells: GZMA binds the LDPRSFLL N-terminal motif of F2R to activate JAK2/STAT1 signaling and drive tumor cell apoptosis while enhancing T cell-mediated killing (PMID:35256589), and the same F2R axis underlies its proangiogenic effects on endothelial cells (PMID:37400946). In intestinal epithelium GZMA exerts opposing barrier-modulating activities through distinct routes: it inhibits PDE4B to trigger a cAMP/PKA/CREB cascade that transactivates GPX4, suppressing ferroptosis and reinforcing tight junctions via Occludin and ZO-1 (PMID:39367435), whereas in sepsis it dephosphorylates GEF-H1 at Ser886 to activate RhoA/ROCK-driven cytoskeletal remodeling that disassembles tight junction proteins and disrupts the barrier (PMID:41943423). GZMA also functions in tissue pathology as a cytotoxic mediator, with CD4+GZMA+ T cells damaging endothelial cells in atherosclerosis (PMID:42237295) and GZMA suppressing dissemination of transformed macrophages (PMID:32830401).

Mechanistic history

Synthesis pass · year-by-year structured walk · 10 steps
  1. 1987 Medium

    Established the cellular source of GZMA by defining where its transcripts are and are not expressed, distinguishing CTL/NK-associated cytotoxicity from macrophage and natural cytotoxicity.

    Evidence Molecular hybridization expression survey across CTLs, NK cells, macrophages, and mast cells

    PMID:3495579

    Open questions at the time
    • Expression survey does not establish protein function
    • Does not address the basis of expression in some non-cytotoxic lymphocytes
  2. 1993 Medium

    Defined GZMA's molecular identity as a homodimeric trypsin-like serine protease in cytotoxic granules and mapped its gene, providing the biochemical foundation for later functional studies.

    Evidence Cosmid cloning, exon-intron mapping, and FISH chromosomal localization to 5q11-q12

    PMID:8288245

    Open questions at the time
    • No substrate identified at this stage
    • Granule localization shown but secretion and target engagement not addressed
  3. 2014 Medium

    Showed that GZMA enzymatic activity is not merely cytotoxic but modulates the Th1/Th2 cytokine balance, expanding its role into immune regulation.

    Evidence Splenocyte assays with serine protease inhibitor AEBSF, cytokine and phospho-STAT6A readouts, in vivo estrogen model

    PMID:24840346

    Open questions at the time
    • Direct protease substrates driving the cytokine shift not identified
    • AEBSF is a broad serine protease inhibitor, not GZMA-specific
  4. 2020 Medium

    Demonstrated a tumor/pathogen-context function in which GZMA suppresses dissemination of transformed macrophages, implicating it in malignancy beyond direct killing.

    Evidence CRISPR/Cas9 knockdown in bovine macrophages, in vivo dissemination in Rag2/γC mice, cancer cell line transcriptomics

    PMID:32830401

    Open questions at the time
    • Molecular mechanism of dissemination suppression unresolved
    • Whether protease activity is required not tested
  5. 2022 Medium

    Identified F2R/PAR1 as a direct GZMA receptor and mapped the binding motif, defining a JAK2/STAT1 apoptotic signaling axis on target cells.

    Evidence Co-IP, F2R LDPRSFLL motif mutagenesis, in vivo tumor model, and T cell killing assays in hepatocellular carcinoma

    PMID:35256589

    Open questions at the time
    • Single Co-IP without independent structural confirmation of the interface
    • Whether cleavage of F2R or non-catalytic binding drives signaling not fully separated
  6. 2023 Low

    Extended the GZMA-F2R axis to endothelial biology, linking it to proangiogenic responses.

    Evidence HUVEC/Jurkat co-culture with recombinant GZMA, RT-PCR, migration and tube formation assays

    PMID:37400946

    Open questions at the time
    • Single recombinant-protein addition experiment without genetic manipulation
    • Downstream F2R signaling cascade in endothelium not dissected
  7. 2023 Low

    Connected GZMA to bone remodeling via osteoclast survival, placing it within a miR-25-3p/TGF-β/PAR1 regulatory circuit.

    Evidence Cas13d-mediated GZMA inhibition in osteoclasts with RT-PCR/Western readouts and proliferation/apoptosis assays

    PMID:37626297

    Open questions at the time
    • No direct biochemical interaction assay
    • Causal ordering of the miR-25-3p/TGF-β/PAR1 axis relative to GZMA unclear
  8. 2024 Medium

    Defined a barrier-protective intestinal pathway in which GZMA inhibits PDE4B to drive cAMP/PKA/CREB-dependent GPX4 transactivation, suppressing ferroptosis and strengthening tight junctions.

    Evidence Co-IP (PKA-CREB), luciferase reporter, subcellular fractionation, intestinal organoids, and DSS colitis mouse model

    PMID:39367435

    Open questions at the time
    • Whether GZMA directly cleaves or binds PDE4B not biochemically resolved
    • Receptor or entry route into epithelial cells not defined
  9. 2026 High

    Established a barrier-disruptive GZMA mechanism in sepsis via Ser886 dephosphorylation of GEF-H1 and RhoA/ROCK-driven cytoskeletal remodeling, contrasting with its protective intestinal role.

    Evidence Site-directed mutagenesis of GEF-H1 Ser886, GEF-H1 KO mice, CLP sepsis model, TEER/permeability assays, plinabulin treatment

    PMID:41943423

    Open questions at the time
    • How a protease produces a net dephosphorylation of GEF-H1 not mechanistically reconciled
    • Reconciliation with the opposing PDE4B/GPX4 barrier-protective pathway unresolved
  10. 2026 Medium

    Implicated CD4+GZMA+ T cells as effectors of endothelial cytotoxicity in atherosclerosis, downstream of cigarette-tar-induced MHC II upregulation.

    Evidence ApoEKO tar inhalation model, scRNA-seq, mass spectrometry of CIITA-PRMT5, CIITA/PRMT5 perturbation, and CD4+Gzma+ T cell/endothelial co-culture

    PMID:42237295

    Open questions at the time
    • GZMA's direct enzymatic role in endothelial damage not biochemically resolved
    • Whether F2R or another receptor mediates the cytotoxicity not tested

Open questions

Synthesis pass · forward-looking unresolved questions
  • It remains unresolved how GZMA reconciles its opposing barrier-protective (PDE4B/GPX4) and barrier-disruptive (GEF-H1/RhoA) intestinal activities, and which catalytic substrates underlie each non-canonical signaling outcome.
  • No unified model of context-dependent GZMA signaling
  • Direct enzymatic substrates for most signaling outputs unidentified
  • Mechanism of GZMA entry/access to intracellular targets like PDE4B and GEF-H1 unknown

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0140096 catalytic activity, acting on a protein 3 GO:0016787 hydrolase activity 2 GO:0048018 receptor ligand activity 2
Localization
GO:0005576 extracellular region 2 GO:0031410 cytoplasmic vesicle 1
Pathway
R-HSA-162582 Signal Transduction 3 R-HSA-168256 Immune System 3 R-HSA-5357801 Programmed Cell Death 2
Partners
F2RGEF-H1PDE4B

Evidence

Reading pass · 10 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
1987 CTLA-3 (GZMA) transcripts are expressed preferentially in cytolytic T lymphocytes but can also be detected in some non-cytotoxic lymphocytes; they are absent in cytotoxic macrophages and most natural cytotoxic cells, indicating CTLA-3/GZMA is not required for macrophage or natural cytotoxicity. Tissue expression survey by molecular hybridization across diverse cell types including CTLs, NK cells, macrophages, and mast cells Journal of immunology Medium 3495579
1993 Human granzyme A (HFSP/CTLA3) is a homodimeric, trypsin-like serine protease of 60 kDa localized in granules of cytolytic T cells and NK cells; its gene maps to chromosome 5q11-q12 and spans 10 kb with a defined exon-intron structure, placing it outside known serine protease superfamily loci. Cosmid clone isolation, complete exon-intron mapping, chromosomal mapping by FISH with an 11-kb genomic probe Genomics Medium 8288245
2014 GZMA serine protease activity promotes proinflammatory cytokine production (IFN-γ, IL-1β, IL-1α) in IL-12-stimulated splenocytes; pharmacological inhibition of serine protease activity with AEBSF diminished GZMA activity and shifted the response toward a Th2 profile (increased IL-4, STAT6A nuclear translocation, GATA3, c-Maf), demonstrating that GZMA enzymatic activity modulates Th1/Th2 balance. In vitro splenocyte assay with serine protease inhibitor AEBSF, cytokine measurement, Western blot for phospho-STAT6A nuclear translocation, in vivo estrogen treatment model Endocrinology Medium 24840346
2020 GZMA functions as a dissemination suppressor in Theileria annulata-transformed macrophages; CRISPR/Cas9-mediated knockdown of GZMA in attenuated macrophages restored their dissemination capacity in Rag2/γC mice, and overexpression of GZMA dampened dissemination potential in human B lymphomas. CRISPR/Cas9 knockdown in bovine macrophages, in vivo dissemination assay in Rag2/γC mice, comparative transcriptomics of 934 human cancer cell lines Cellular microbiology Medium 32830401
2022 GZMA secreted by cytotoxic cells binds to F2R (PAR1) expressed on tumor cells via the LDPRSFLL motif at the N-terminus of F2R; this interaction activates the JAK2/STAT1 signaling pathway, promotes tumor cell apoptosis, and enhances T cell-mediated tumor killing in hepatocellular carcinoma. Co-immunoprecipitation, in vivo mouse tumor model, in vitro T cell killing assays, motif mutagenesis identifying the LDPRSFLL N-terminal motif of F2R, single-cell sequencing Cell death & disease Medium 35256589
2023 GZMA promotes angiogenesis in endothelial cells via interaction with F2R (PAR1); addition of GZMA recombinant protein to HUVECs co-cultured with Jurkat T cells increased F2R expression and enhanced endothelial migration and tube formation. In vitro co-culture of HUVECs and Jurkat T cells with GZMA recombinant protein, RT-PCR, angiogenesis assay, migration assay International endodontic journal Low 37400946
2023 GZMA promotes osteoclast proliferation and inhibits osteoclast apoptosis; Cas13d-mediated inhibition of GZMA increased miR-25-3p expression, which downregulated TGF-β, leading to decreased PAR1 (PAR1/PARs pathway) expression in osteoclasts during chronic apical periodontitis. crRNA/Cas13d-mediated GZMA inhibition in osteoclasts, RT-PCR and Western blot for miR-25-3p, TGF-β, and PAR1, cell proliferation and apoptosis assays Cellular & molecular biology letters Low 37626297
2024 GZMA inhibits PDE4B activity in intestinal epithelial cells, triggering the cAMP/PKA/CREB signaling cascade; PKA interacts with CREB (interaction enhanced by GZMA), leading to CREB nuclear translocation and transactivation of GPX4, which inhibits ferroptosis and promotes CDX2-mediated cell differentiation, increasing Occludin and ZO-1 expression to improve intestinal barrier function. Western blot, qPCR, immunofluorescence, in vitro permeability assay, intestinal organoid culture, luciferase reporter assay, co-immunoprecipitation (PKA-CREB), subcellular fractionation, DSS-induced colitis mouse model Cell communication and signaling Medium 39367435
2026 GZMA (secreted by activated immune cells) activates GEF-H1 by dephosphorylating Ser886, which triggers the RhoA/ROCK pathway and subsequent phosphorylation of MLC2, LIMK, and cofilin, driving cytoskeletal remodeling and disruption of tight junction proteins (occludin, claudin-1, ZO-1, E-cadherin), thereby impairing the intestinal epithelial barrier during sepsis. In vitro immune cell–epithelial co-culture, TEER measurement, permeability assay, site-directed mutagenesis (Ser886 on GEF-H1), GEF-H1 knockout mice, CLP sepsis mouse model, high-throughput drug screening, plinabulin (GEF-H1 activator) treatment Clinical and translational medicine High 41943423
2026 CD4+GZMA+ T cells cause endothelial cell cytotoxicity in atherosclerosis; cigarette tar promotes CIITA nuclear translocation and PRMT5-mediated H3R2 symmetric dimethylation, upregulating MHC II expression on endothelial cells, which activates CD4+Gzma+ T cells that in turn damage endothelial cells. ApoEKO mouse cigarette tar inhalation model, scRNA-seq, mass spectrometry identifying CIITA-PRMT5 interaction, CIITA knockout/knockdown, PRMT5 inhibition/knockdown, in vitro co-culture of CD4+Gzma+ T cells with endothelial cells BMC medicine Medium 42237295

Source papers

Stage 0 corpus · 17 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
1987 CTLA-1 and CTLA-3 serine esterase transcripts are detected mostly in cytotoxic T cells, but not only and not always. Journal of immunology (Baltimore, Md. : 1950) 64 3495579
2022 Heterogeneity induced GZMA-F2R communication inefficient impairs antitumor immunotherapy of PD-1 mAb through JAK2/STAT1 signal suppression in hepatocellular carcinoma. Cell death & disease 34 35256589
2018 HFSP: high speed homology-driven function annotation of proteins. Bioinformatics (Oxford, England) 32 29950013
2024 GZMA suppressed GPX4-mediated ferroptosis to improve intestinal mucosal barrier function in inflammatory bowel disease. Cell communication and signaling : CCS 19 39367435
2020 Novel tumour suppressor roles for GZMA and RASGRP1 in Theileria annulata-transformed macrophages and human B lymphoma cells. Cellular microbiology 16 32830401
1993 The human granzyme A (HFSP, CTLA3) gene maps to 5q11-q12 and defines a new locus of the serine protease superfamily. Genomics 13 8288245
2023 Heterogeneity of T cells in periapical lesions and in vitro validation of the proangiogenic effect of GZMA on HUVECs. International endodontic journal 10 37400946
2023 CRISPR/Cas13d targeting GZMA in PARs pathway regulates the function of osteoclasts in chronic apical periodontitis. Cellular & molecular biology letters 6 37626297
2014 Serine protease inhibition attenuates rIL-12-induced GZMA activity and proinflammatory events by modulating the Th2 profile from estrogen-treated mice. Endocrinology 5 24840346
2025 GZMA silencing inhibits JAK2/STAT1 pathway and improves allergic rhinitis. General physiology and biophysics 3 40116417
2025 Exhausted KLRG1hi CD8+ T and pathogenic GZMA+ Th17 cells are associated with the mild Mycoplasma pneumoniae pneumonia in children. The Journal of infection 2 41173398
2024 The role of GZMA as a target of cysteine and biomarker in Alzheimer's disease, pelvic organ prolapse, and tumor progression. Frontiers in pharmacology 1 39228516
2026 Preliminary Study on GZMA- and GSDMB-Associated Pyroptosis and CD8+ T Cell-Mediated Immune Evasion in Skin Cutaneous Melanoma. Current topics in medicinal chemistry 0 40755114
2026 Mechanism of Gzma-mediated GEF-H1 activation in intestinal epithelial cells leading to intestinal barrier dysfunction in sepsis. Clinical and translational medicine 0 41943423
2026 CIITA/PRMT5 promote CD4+Gzma+ T cell activation via H3R2me2-mediated endothelial expression of MHC class II in smoking-induced atherosclerosis. BMC medicine 0 42237295
2025 Integrated multi-omics identifies GZMA targeting NK cells as a novel therapeutic strategy for hidradenitis suppurativa. SLAS technology 0 41192724
1992 Development shows some backbone. HFSP Workshop on Genetic Control of Vertebrate Development cosponsored by the Human Frontier Science Program, European Science Foundation, and European Molecular Biology Organization, Les Diablerets, Switzerland, May 26-30, 1991. The New biologist 0 1346970

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