Inflammation and the ADAM Family

The ADAM (A Disintegrin And Metalloproteinase) and ADAMTS (ADAM with ThromboSpondin motifs) families constitute zinc-dependent metalloproteinases that regulate inflammatory signaling through ectodomain shedding, cytokine activation, and extracellular matrix remodeling. Since their initial characterization in the mid-1990s, these enzymes have been implicated in tumor necrosis factor-α (TNF-α) processing, amyloid precursor protein cleavage, leukocyte extravasation, and complement cascade activation. Understanding ADAM biology requires validated reagents that distinguish closely related family members.

ADAMs — disintegrin and metalloproteinase architecture

ADAM proteases share a conserved multidomain architecture: an N-terminal prodomain, a catalytic metalloproteinase domain bearing the HEXXHXXGXXH zinc-binding motif, a disintegrin domain that mediates integrin binding, a cysteine-rich region, an EGF-like repeat, a transmembrane segment, and a cytoplasmic tail. This architecture enables dual functions—proteolytic cleavage of membrane-anchored substrates and cell-adhesion signaling via the disintegrin domain. Mammals express 21 ADAM genes, roughly half of which encode catalytically active proteases; the remainder have lost proteolytic activity through mutation of the zinc-binding consensus but retain adhesive functions.

Active ADAMs perform ectodomain shedding, a post-translational modification in which the extracellular portion of a transmembrane protein is cleaved near the membrane, releasing a soluble ectodomain and leaving a membrane-tethered C-terminal fragment. This process regulates receptor availability, ligand bioactivity, and signal termination. ADAM-mediated shedding is constitutive for some substrates and inducible for others, often triggered by inflammatory mediators, oxidative stress, or calcium ionophores. Several ADAMs exhibit restricted tissue expression: Anti-ADAM-1 Antibody and Anti-ADAM-2 Antibody are used to detect fertilization-related proteases in testis and epididymis, whereas Anti-ADAM-8 Antibody detects a leukocyte-restricted protease upregulated in monocytes and dendritic cells during inflammation.

ADAM17 (TACE) and TNF-α processing

ADAM17, also known as TNF-α converting enzyme (TACE), is the principal sheddase for pro-TNF-α, converting the 26 kDa membrane-bound precursor into the 17 kDa soluble cytokine that drives systemic inflammation. ADAM17 was cloned in 1997 through expression screening for enzymes capable of releasing TNF-α from the cell surface. Genetic ablation of ADAM17 in mice is perinatal lethal with defects resembling combined EGFR and TNF-receptor deficiency, confirming its essential role in cytokine and growth-factor signaling. Beyond TNF-α, ADAM17 cleaves more than 80 substrates, including TNF receptors (TNFR1, TNFR2), IL-6 receptor, L-selectin, and multiple EGFR ligands (TGF-α, amphiregulin, HB-EGF). Detection of ADAM17 with Anti-ADAM-17 Antibody by Western blot reveals the full-length ~100 kDa mature enzyme in lysates from stimulated macrophages and epithelial cells.

ADAM17 activity is tightly regulated. The prodomain maintains latency until cleavage by furin in the Golgi. Phosphorylation of the cytoplasmic tail by MAP kinases and PKC modulates substrate selectivity. Tissue inhibitors of metalloproteinases (TIMPs) provide endogenous inhibition; TIMP-3 is the most potent ADAM17 inhibitor. Rheumatoid synovium and atherosclerotic plaques exhibit elevated ADAM17 expression, and selective ADAM17 inhibitors have been explored as anti-inflammatory therapeutics, though clinical development has been hampered by on-target toxicity related to EGFR ligand shedding.

Why is ADAM17 also called TACE?

ADAM17 is called TACE (TNF-α Converting Enzyme) because it was identified in 1997 as the protease responsible for cleaving membrane-bound pro-TNF-α into its soluble, bioactive form. This proteolytic conversion is essential for TNF-α release during inflammatory responses. The enzyme was independently cloned by two groups and named for its signature substrate, though it is now recognized to shed more than 80 different membrane proteins beyond TNF-α.

What is ectodomain shedding and which enzymes do it?

Ectodomain shedding is the proteolytic cleavage of the extracellular domain of a transmembrane protein near the cell surface, releasing a soluble fragment into the extracellular space. ADAMs, particularly ADAM10 and ADAM17, are the principal sheddases in mammalian cells. ADAM17 sheds TNF-α, TNFR1, IL-6R, and L-selectin, while ADAM10 sheds Notch, CD44, and E-cadherin. Matrix metalloproteinases (MMPs) and some ADAMTS members also perform limited ectodomain cleavage. Shedding regulates receptor signaling, ligand availability, and cell adhesion in inflammation, development, and cancer.

ADAM10 — α-secretase activity beyond Alzheimer's

ADAM10 is the constitutive sheddase for a distinct substrate repertoire, most notably serving as the α-secretase that cleaves amyloid precursor protein (APP) within the amyloid-β sequence, precluding formation of neurotoxic Aβ peptides. Genetic deletion of ADAM10 in mice causes embryonic lethality due to defects in Notch and ErbB signaling, underscoring its essential developmental roles. In the immune system, ADAM10 sheds CD23, CD44, CX3CL1 (fractalkine), and CXCL16, thereby modulating B-cell activation, leukocyte migration, and chemokine presentation on endothelium.

ADAM10 is upregulated in activated T cells and macrophages. Its shedding of CD163, the hemoglobin-haptoglobin scavenger receptor, generates soluble CD163 (sCD163), a biomarker of macrophage activation in sepsis and hemophagocytic syndromes. Etzerodt and colleagues (2014) demonstrated that inflammatory stimuli—particularly lipopolysaccharide and oxidative stress—trigger ADAM10-mediated CD163 shedding in human macrophages, and that sCD163 levels correlate with disease severity in bacterial sepsis¹. The Anti-ADAM-10 Antibody detects the ~84 kDa mature protease and is validated for Western blot in lysates from brain, spleen, and cultured immune cells.

What is the difference between ADAM10 and ADAM17?

ADAM10 and ADAM17 are both membrane-anchored sheddases but differ in substrate specificity, regulation, and biological roles. ADAM10 is the constitutive α-secretase for APP and the principal sheddase for Notch ligands, CD44, and CX3CL1, and is essential for embryonic development. ADAM17 is the inducible sheddase for TNF-α, IL-6R, and EGFR ligands, activated by inflammatory signals and phorbol esters. ADAM17 deficiency is perinatal lethal in mice, whereas ADAM10 knockout causes earlier embryonic death. Their cytoplasmic tails differ, conferring distinct regulation by kinases and adaptor proteins.

ADAMTS proteases — ECM and immunology roles

The ADAMTS family comprises 19 secreted metalloproteinases characterized by a thrombospondin type-1 repeat (TSR) motif C-terminal to the catalytic domain. Unlike membrane-bound ADAMs, ADAMTS proteases are secreted into the extracellular space and act on matrix substrates—aggrecan, versican, collagen—and on soluble proteins such as von Willebrand factor (vWF). ADAMTS-13 cleaves ultralarge vWF multimers; loss-of-function mutations or autoantibodies against ADAMTS-13 cause thrombotic thrombocytopenic purpura (TTP). The Anti-ADAMTS-13 Antibody is used in Western blot and ELISA to measure plasma ADAMTS-13 levels in TTP diagnostics.

In inflammation, several ADAMTS members regulate leukocyte trafficking and matrix turnover. ADAMTS-1 and ADAMTS-4 cleave versican, facilitating leukocyte extravasation and smooth-muscle migration. Anti-ADAMTS-4 Antibody and Anti-ADAMTS-5 Antibody detect aggrecanases implicated in cartilage degradation during osteoarthritis and rheumatoid arthritis. ADAMTS-7 is expressed in vascular smooth muscle and macrophages within atherosclerotic plaques and promotes plaque destabilization. ADAMTS-2, -3, and -14 are procollagen N-proteinases essential for collagen fibril assembly; mutations cause Ehlers-Danlos syndrome variants. Coverage includes Anti-ADAMTS-1 Antibody, Anti-ADAMTS-2 Antibody, and reagents spanning ADAMTS-3 through ADAMTS-20.

Complement-associated proteases — MASP-1, MASP-2

Mannose-binding lectin-associated serine proteases (MASPs) initiate the lectin pathway of complement activation. MASP-1 and MASP-2 circulate as zymogens bound to pattern-recognition molecules—mannose-binding lectin (MBL) and ficolins—that recognize microbial carbohydrates. Upon ligand binding, MASP-1 autoactivates and cleaves MASP-2, which in turn cleaves complement C4 and C2, forming the C3 convertase. MASP-3, encoded by the same gene as MASP-1 through alternative splicing, activates pro-factor D in the alternative pathway.

MASP proteases contribute to sterile inflammation and ischemia-reperfusion injury. MASP-2 inhibition attenuates myocardial infarct size in animal models, and a humanized anti-MASP-2 antibody has entered clinical trials for transplant rejection. The Anti-MASP-1 Antibody and Anti-MASP-2 Antibody detect the ~80–90 kDa zymogens and activated heavy chains in serum and tissue lysates by Western blot and immunohistochemistry.

What role do MASP proteases play in inflammation?

MASP proteases (MASP-1, MASP-2, MASP-3) initiate the lectin pathway of complement by recognizing microbial or altered-self carbohydrate patterns via mannose-binding lectin and ficolins. MASP-2 cleaves C4 and C2 to form the C3 convertase, amplifying complement activation and generating anaphylatoxins (C3a, C5a) that recruit and activate leukocytes. MASP-1 activates MASP-2 and also cleaves fibrinogen and factor XIII, linking complement to coagulation. MASP-mediated complement activation occurs in ischemia-reperfusion injury, transplant rejection, and autoimmune disease, independent of antibody.

Neutrophil granule proteases — elastase, cathepsin G, proteinase 3

Neutrophil serine proteases—neutrophil elastase (NE), cathepsin G (CG), and proteinase 3 (PR3)—are stored in azurophil granules and released during degranulation and NETosis. These proteases degrade extracellular matrix, cleave complement components and cytokines, and inactivate bacterial virulence factors. NE cleaves elastin, collagen, and fibronectin, facilitating tissue penetration; it also processes IL-1β, IL-18, and TNF-α, modulating inflammatory signaling. Dysregulated NE activity contributes to acute lung injury, chronic obstructive pulmonary disease (COPD), and cystic fibrosis pathology.

Cathepsin G exhibits chymotrypsin-like specificity and activates protease-activated receptor-4 (PAR-4) on platelets. Proteinase 3 is a chymotrypsin-fold serine protease and the autoantigen in granulomatosis with polyangiitis (Wegener's); anti-PR3 antibodies (c-ANCA) drive neutrophil activation and vascular inflammation. Azurocidin, a homologous but catalytically inactive granule protein, functions as a monocyte chemoattractant and antimicrobial lectin. Detection reagents include Anti-Elastase-2 Antibody, Anti-Cathepsin G Antibody, Anti-Proteinase-3 Antibody, and Anti-Azurocidin Antibody, validated for Western blot in neutrophil-rich tissues.

Granzymes — cytotoxic T-cell and NK biology

Granzymes are serine proteases stored in cytotoxic granules of CD8+ T cells and natural killer (NK) cells. Upon immune-synapse formation, granzymes are co-released with perforin, which permeabilizes the target-cell membrane, allowing granzyme entry. Granzyme B (GzmB), the most abundant and best characterized, cleaves after aspartate residues, activating caspases and the executioner machinery of apoptosis. GzmB also cleaves BID, initiating mitochondrial outer-membrane permeabilization, and directly degrades cytoskeletal and nuclear proteins, ensuring rapid target-cell death.

Humans express five granzymes: A, B, H, K, and M. Granzyme A (GzmA) triggers caspase-independent cell death through cleavage of the SET complex, releasing the nuclease NM23-H1. Granzyme H and K exhibit tryptase-like specificity and are upregulated in activated NK cells. Extracellular granzymes, released during chronic viral infection or autoimmunity, cleave extracellular matrix proteins and modulate inflammation independently of cytotoxicity. The Anti-Granzyme-A Antibody, Anti-Granzyme-B Antibody, Anti-Granzyme-H Antibody, and Anti-Granzyme K Antibody detect the ~30 kDa mature proteases in lysates from activated lymphocytes and are widely used in immunohistochemistry to quantify cytotoxic infiltrates in tumors and inflamed tissues.

Inflammation-focused antibody panel recommendations

Designing antibody panels for inflammation studies requires balancing breadth of coverage with depth in specific pathways. For TNF-α and cytokine shedding, a minimal panel includes Anti-ADAM-17 Antibody and Anti-ADAM-10 Antibody, covering the two dominant sheddases. Investigators studying leukocyte adhesion and extravasation should add Anti-ADAM-8 Antibody and Anti-ADAMTS-1 Antibody to monitor monocyte-restricted proteases and versican processing.

For complement-driven inflammation, Anti-MASP-1 Antibody and Anti-MASP-2 Antibody detect lectin-pathway initiators; pairing these with neutrophil granule protease antibodies (Anti-Elastase-2 Antibody, Anti-Cathepsin G Antibody) captures the full spectrum of innate immune proteolysis. In cancer immunology and transplant studies, granzyme panels are essential: Anti-Granzyme-B Antibody for cytotoxic function and Anti-Granzyme-A Antibody for caspase-independent killing.

When working across species, confirm predicted cross-reactivity. Mouse and human ADAMs share 70–90% sequence identity in their catalytic domains, and most rabbit polyclonals raised against human sequences detect mouse orthologs by Western blot. Validation in pilot experiments with species-matched positive controls is standard practice.

TPB's ADAM, ADAMTS, and inflammation coverage

Triple Point Biologics has supplied rabbit polyclonal antibodies to proteinase researchers since 1994. The catalog includes 22 anti-ADAM antibodies spanning fertilization proteases (ADAM-1, ADAM-2), neuronal and muscle ADAMs (ADAM-11, ADAM-12, ADAM-19), and the catalytically inactive adhesion receptors (ADAM-22, ADAM-23). Additional ADAMs available include ADAM-7, ADAM-9, ADAM-13, ADAM-15, ADAM-18, ADAM-20, ADAM-21, ADAM-28, ADAM-29, ADAM-30, ADAM-32, and ADAM-33.

ADAMTS coverage includes 20 antibodies: aggrecanases (ADAMTS-4, ADAMTS-5), procollagen N-proteinases (ADAMTS-2, ADAMTS-3, ADAMTS-14), the vWF protease ADAMTS-13, and members implicated in angiogenesis and development (ADAMTS-1, ADAMTS-9, ADAMTS-15). Additional ADAMTS antibodies cover ADAMTS-6, ADAMTS-7, ADAMTS-8, ADAMTS-10, ADAMTS-12, ADAMTS-16, ADAMTS-17, ADAMTS-18, ADAMTS-19, and ADAMTS-20.

Complement and innate immunity reagents include Anti-MASP-1 Antibody, Anti-MASP-2 Antibody, and Anti-MASP-3 Antibody for lectin-pathway studies. Neutrophil serine proteases are covered by Anti-Elastase-2 Antibody, Anti-Cathepsin G Antibody, Anti-Proteinase-3 Antibody, and Anti-Azurocidin Antibody. For cytotoxic lymphocyte research, granzyme reagents include Anti-Granzyme-A Antibody, Anti-Granzyme-B Antibody, Anti-Granzyme-H Antibody, and Anti-Granzyme K Antibody.

All antibodies are affinity-purified rabbit polyclonals validated for Western blot; many are also validated for immunohistochemistry. Predicted cross-reactivity with mouse and rat orthologs is provided on product datasheets. Products are supplied as liquid in PBS with preservative, typically in 100 µg aliquots suitable for 20–50 blots depending on target abundance. Research-use-only; not for diagnostic or therapeutic use.

References

1. Etzerodt A et al. Structural basis for inflammation-driven shedding of CD163 ectodomain and tumor necrosis factor-α in macrophages. J Biol Chem. 2014;289(2):778-88. PMID: 24275664. DOI: 10.1074/jbc.M113.520213