Isolation and Serine Protease Inhibitory Activity of the 44-Residue, C-Terminal Fragment of αl -Antitrypsin from Human Placenta

Niemann, Marilyn A.; Narkates, A. J.; Miller, Edward J.

doi:10.1016/s0934-8832(11)80066-1

Cited by 30 publications

(26 citation statements)

References 5 publications

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“…A1AT is abundant in human placental tissue compartments (60,61). It has been proposed that progressive proteolytic cleavage of A1AT occurs in the placenta, and proteases that mediate enzymatic fragmentation of A1AT to A1ATm 358 in vitro are known (39,62,63), although a specific placental protease has not been identified. A protease that is increased in human placental syncytiotrophoblasts in the third trimester of pregnancy, high temperature requirement protease 1, cleaves A1AT in the carboxy terminus (61).…”

Section: Discussionmentioning

confidence: 99%

Neonatal NET-inhibitory factor and related peptides inhibit neutrophil extracellular trap formation

Yost

Schwertz

Cody

et al. 2016

Journal of Clinical Investigation

123

133

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Section: Discussionmentioning

confidence: 99%

Neonatal NET-inhibitory factor and related peptides inhibit neutrophil extracellular trap formation

Yost

Schwertz

Cody

et al. 2016

Journal of Clinical Investigation

123

133

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“…We have observed similar properties for the serpin, kallistatin (16,17). The predicated molecular mass of PBP (mouse or human) is estimated at ϳ47 kDa, given the 40-kDa apparent molecular mass of prostasin and considering the fact that serpin molecules lose a carboxylterminal fragment of ϳ5 kDa when complexed with a serine protease (31).…”

Section: Identification Of a Prostasin-binding Protein-anmentioning

confidence: 99%

Prostasin Is a Glycosylphosphatidylinositol-anchored Active Serine Protease

Chen

Skinner

Kauffman

et al. 2001

Journal of Biological Chemistry

111

151

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A recombinant human prostasin serine protease was expressed in several human cell lines. Subcellular fractionation showed that this serine protease is synthesized as a membrane-bound protein while a free-form prostasin is secreted into the culture medium. Prostasin was identified in nuclear and membrane fractions. Membrane-bound prostasin can be released by phosphatidylinositol-specific phospholipase C treatment, or labeled by [ 3 H]ethanolamine, indicating a glycosylphosphatidylinositol anchorage. A prostasin-binding protein was identified in mouse and human seminal vesicle fluid. Both the secreted and the membrane-bound prostasin were able to form a covalently linked 82-kDa complex when incubated with seminal vesicle fluid. The complex formation between prostasin and the prostasin-binding protein was inhibited by a prostasin antibody, heparin, and serine protease inhibitors. Prostasin's serine protease activity was inhibited when bound to the prostasin-binding protein in mouse seminal vesicle fluid. This study indicates that prostasin is an active serine protease in its membrane-bound form.Prostasin is a serine protease discovered in ejaculated human semen in 1994 (1). The molecular mass of prostasin is 40 kDa when examined by SDS-polyacrylamide gel electrophoresis (PAGE) 1 under reducing conditions. Prostasin displays trypsin-like enzymatic activities by hydrolyzing peptidyl fluorogenic substrates such as D-Pro-Phe-Arg-AMC. This trypsinlike enzymatic activity can be inhibited by aprotinin, antipain, leupeptin, and benzamidine. Prostasin is present at high levels in normal human semen (8.61 Ϯ 0.42 g/ml) and in the prostate gland (143.7 Ϯ 15.9 ng/mg). Lower amounts of prostasin can also be detected in other tissues. In the prostate gland, the prostasin protein is present in the epithelial cells as well as in the secretion inside the lumen. The full-length human prostasin mRNA has been deduced (2). The predicted mature prostasin peptide sequence has a potential carboxyl-terminal hydrophobic membrane anchorage domain followed by a short cytoplasmic tail. The translated amino acid residue sequence of prostasin is similar to those of human prostase, testisin, plasma kallikrein, coagulation factor XI, hepsin, plasminogen, and acrosin (2-4). A membrane-bound Xenopus kidney epithelial cell sodium channel-activating protease (CAP1) was found highly homologous to human prostasin, sharing 53% sequence identity at the amino acid level (5). Recently, the mouse counterpart of CAP1, mCAP1, has been cloned from a cortical collecting duct cell line (6). mCAP1 shares 77% amino acid sequence identity with human prostasin.Serine proteases play important roles in a diverse range of the body's normal physiological processes, and they are implicated in various pathological processes such as cardiovascular disorders and cancers (7). The prostate produces a number of serine proteases such as prostate-specific antigen (8), human glandular kallikrein (9), and the most recently discovered prostase (3). Some of these serine proteases are ...

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“…17 Immunohistochemical studies indicate that cleaved fragments of AAT, including a 44-residue C-terminal fragment, arising from proteolytic cleavage within the reactive site loop of AAT, may be present in a variety of human tissues, such as placenta, pancreas, stomach, and small intestine. [18][19][20] In addition, this 44-residue C-terminal peptide of AAT was found to be associated with extracellular matrix proteins such as collagen and/or laminin-1, and it was suggested that AAT peptide plays an important role in the protection of these proteins from inappropriate enzyme digestion. 21 Using monoclonal antibodies raised against the cleaved form of AAT, increased levels of inactivated AAT were found in synovial fluid from patients with rheumatoid arthritis corresponding to about 2.4% of total AAT.…”

mentioning

confidence: 99%

Effects of Fibrillar C–Terminal Fragment of Cleaved α1–Antitrypsin on Cholesterol Homeostasis in Hepg2 Cells

Janciauskiene

Lindgren

1999

Hepatology

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The family of serine proteinase inhibitors (serpins) is a class of proteins that can adopt multiple conformations and exist in various physical forms, some of which are known to be pathogenic. 1,2 Serpins can exist as native (active), cleaved (inactive), latent (inactive, but not cleaved), complexed with target enzyme, and polymerized forms, and it has been suggested that these conformers have not only diverse functional properties at the cellular level and different elimination rates, but also may exhibit new physiological functions. 3,4 ␣ 1 -Antitrypsin (AAT) is the prototypic member of the serpin family and primarily inhibits neutrophil elastase and proteinase 3. 5 AAT is an acute-phase protein, predominantly synthesized by the liver, the concentration of which during the acute-phase processes rises by three-to fourfold that of normal (1.34 mg/mL). 1 It follows that levels of AAT-elastase complexes also increase, a conclusion supported by the observation that, e.g., in acute leukemia patients, AATelastase complex levels are found to be more than 10 times higher than normal. 6 Formation of a stable, covalent complex between AAT and its target enzyme is associated with cleavage of the serpinreactive center loop, generating a 4-kd carboxyl-terminal fragment of 36 residues. This peptide remains non-covalently bound to the cleaved AAT in complex with enzymes and also to the core of cleaved AAT, dissociated from the complex. 3 The peptide can be separated from the cleaved AAT under denaturing conditions in vitro. Joslin et al. showed that proteolytically cleaved AAT binds to receptors on HepG2 cells and that binding is mediated by the same domain within the carboxyl-terminal fragment of AAT as for AAT-enzyme complexes. 7 Results from their studies using AAT-elastase complexes and purified fragments of AAT confirmed that a domain within the 4-kd carboxyl-terminal fragment of AAT is necessary for binding to these serpin-enzyme complex (SEC) receptor(s), and that such a domain is available for receptor binding only when AAT forms a complex with serine proteinase or when it is proteolytically modified. Recently, it was demonstrated that cellular internalization and degradation of antithrombin-thrombin, AAT-elastase, AAT-trypsin, urokinasetype plasminogen activator-plasminogen activator inhibitor-1, and some other SECs, but not native or cleaved forms of serpins, is mediated by the low-density lipoprotein receptorrelated protein 8 and very-low-density lipoprotein receptor. 9 Identification that protease-serpin complexes are recognized by endocytosis receptors of the low-density lipoprotein (LDL) receptor family suggests that those receptors play a role in both lipoprotein metabolism and proteinase regulation during the inflammatory response. In our previous work, we showed that proteolytically cleaved AAT increases LDL binding and uptake by up to 70% in a concentration-and time-dependent manner in HepG2 cells, suggesting a possible Abbreviations: AAT, ␣ 1 -antitrypsin; SEC, serpin-enzyme complex; LDL, low-density lipopr...

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Isolation and Serine Protease Inhibitory Activity of the 44-Residue, C-Terminal Fragment of αl -Antitrypsin from Human Placenta

Cited by 30 publications

References 5 publications

Neonatal NET-inhibitory factor and related peptides inhibit neutrophil extracellular trap formation

Neonatal NET-inhibitory factor and related peptides inhibit neutrophil extracellular trap formation

Prostasin Is a Glycosylphosphatidylinositol-anchored Active Serine Protease

Effects of Fibrillar C–Terminal Fragment of Cleaved α1–Antitrypsin on Cholesterol Homeostasis in Hepg2 Cells

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