Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Netherton syndrome is a congenital ichthyosis associated with erythroderma, hair shaft defects, and atopic features. The mutations of the secretory serine protease inhibitor Kazal-type 5 gene have been identified in Netherton syndrome patients; however, the actual physiologic substrates of the serine protease inhibitor Kazal-type 5 proprotein are unknown, and how the genetic defects cause characteristic skin phenotype remains uncertain. Here, we describe the serine protease inhibitor Kazal-type 5 gene mutations, including two novel non-sense mutations, and genotype-phenotype correlation in three Netherton syndrome patients in two unrelated Japanese families. Furthermore, based on the reappraisal of the structure of the serine protease inhibitor Kazal-type 5 proprotein, demonstration of the presence of carboxypeptidase in normal keratinocytes, and the observation of mRNA localization of the serine protease inhibitor Kazal-type 5 transcripts in the uppermost epidermis as well as pilosebaceous units, we propose a hypothetical model of proteolytic processing of the serine protease inhibitor Kazal-type 5 proprotein in the epidermis and inhibitory regulation of corneocyte desquamation by a set of serine protease inhibitor Kazal-type 5-derived peptides. This hypothesis is supported by the marked increase of trypsin-like hydrolytic activity demonstrated in stratum corneum samples from our Netherton syndrome patients. The findings in this study suggest that the defective inhibitory regulation of desquamation due to the serine protease inhibitor Kazal-type 5 gene mutations may cause over-desquamation of corneocytes in Netherton syndrome, leading to severe skin permeability barrier dysfunction.
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PMID:Elevated stratum corneum hydrolytic activity in Netherton syndrome suggests an inhibitory regulation of desquamation by SPINK5-derived peptides. 1187 82

Proteinase inhibitors are important negative regulators of proteinase action in vivo and are thus involved in several pathophysiological processes. Starting with the isolation of two new peptides from human blood filtrate, we succeeded in cloning a cDNA encoding the precursor protein for a novel 15-domain Kazal-type-related serine proteinase inhibitor. Two of the 15 domains almost exactly match the Kazal-type pattern, whereas the other 13 domains exhibit only four instead of six cysteine residues. Since the corresponding gene is expressed in several lympho-epithelial tissues, we termed this inhibitor lympho-epithelial Kazal-type-related inhibitor (LEKTI). For three of the 15 LEKTI domains, we demonstrated a significant trypsin-inhibiting activity. Recent results of another group show a relation between mutations within the LEKTI gene and the severe congenital disorder Netherton syndrome. In this review article, we give an overview of the already known data on the structure, processing, gene expression, and pathophysiological role of LEKTI.
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PMID:LEKTI: a multidomain serine proteinase inhibitor with pathophysiological relevance. 1194 86

Based on the isolation of a 55 amino acid peptide from human hemofiltrate, we cloned the cDNA for a novel human 15-domain serine proteinase inhibitor termed LEKTI. A trypsin-inhibiting activity was demonstrated for three different domains. High levels of expression of the corresponding gene were detected in oral mucosa, followed by the tonsils, parathyroid glands, thymus, and trachea. Hovnanian and coworkers recently found that certain mutations within the LEKTI gene are linked to the severe congenital disease Netherton syndrome and atopic manifestations (including asthma). Thus, a future therapeutic use of LEKTI is conceivable.
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PMID:Biochemical features, molecular biology and clinical relevance of the human 15-domain serine proteinase inhibitor LEKTI. 1243 98

The human LEKTI gene encodes a putative 15-domain serine proteinase inhibitor and has been linked to the inherited disorder known as Netherton syndrome. In this study, human recombinant LEKTI (rLEKTI) was purified using a baculovirus/insect cell expression system, and the inhibitory profile of the full-length rLEKTI protein was examined. Expression of LEKTI in Sf9 cells showed the presence of disulfide bonds, suggesting the maintenance of the tertiary protein structure. rLEKTI inhibited the serine proteinases plasmin, subtilisin A, cathepsin G, human neutrophil elastase, and trypsin, but not chymotrypsin. Moreover, rLEKTI did not inhibit the cysteine proteinase papain or cathepsin K, L, or S. Further, rLEKTI inhibitory activity was inactivated by treatment with 20 mM DTT, suggesting that disulfide bonds are important to LEKTI function. The inhibition of plasmin, subtilisin A, cathepsin G, elastase, and trypsin by rLEKTI occurred through a noncompetitive-type mechanism, with inhibitory constants (K(i)) of 27 +/- 5, 49 +/- 3, 67 +/- 6, 317 +/-36, and 849 +/- 55 nM, respectively. Thus, LEKTI is likely to be a major physiological inhibitor of multiple serine proteinases.
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PMID:Inhibition of serine proteinases plasmin, trypsin, subtilisin A, cathepsin G, and elastase by LEKTI: a kinetic analysis. 1266 78

The secretory lympho-epithelial Kazal-type-inhibitor (LEKTI) is synthesized as a pro-LEKTI protein containing an N-terminal signal peptide and 15 potentially inhibitory domains. This inhibitor is of special interest because of its pathophysiological importance for the severe congenital disease Netherton syndrome. We showed that LEKTI is a potent inhibitor of a family of serine proteinases involved in extracellular matrix remodeling and its expression is downregulated in head and neck squamous cell carcinomas. To assess the role of C-terminal domains and N-terminal signal peptide in LEKTI secretion, we constructed deletion mutants of LEKTI, expressed them in HEK 293T cells, and analyzed their secretion behavior, stability, subcellular distribution, and proteinase inhibitory function. Pro-LEKTI is processed and secreted into the medium. On the basis of partial N-terminal sequencing and immunoblotting, the cleavage products are ordered from amino- to carboxy-terminal as follows: 37, 40, and 60kDa. Inhibitors of furin lead to enhanced secretion of unprocessed LEKTI, suggesting that processing was not required for secretion. Deletion of the N-terminal signal peptide of pro-LEKTI caused altered distribution of LEKTI from endoplasmic reticulum (ER) to cytoplasm and markedly reduced its stability, consistent with its failure to become secreted into the medium. Interestingly, when we deleted the C-terminal domains, stable partial LEKTI (LD-1-6) accumulated and still retained its association with ER but was not secreted. Recombinant LD-1-6 specifically inhibited the trypsin activity. We conclude that N-terminal signal peptide is required for LEKTI import into ER and elements present in C-terminal domains may have a role in regulating LEKTI secretion.
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PMID:Consequences of C-terminal domains and N-terminal signal peptide deletions on LEKTI secretion, stability, and subcellular distribution. 1568 Sep 11

LEKTI is a 120-kDa protein that plays an important role in skin development, as mutations affecting LEKTI synthesis underlie Netherton syndrome, an inherited skin disorder producing severe scaling. Its primary sequence indicates that the protein consists of 15 domains, all resembling a Kazal-type serine protease inhibitor. LEKTI and two serine proteases belonging to the human tissue kallikrein (hK) family (hK5 and hK7) are expressed in the granular layer of skin. In this study, we characterize the interaction of two recombinant LEKTI fragments containing three or four intact Kazal domains (domains 6-8 and 9-12) with recombinant rhK5, a trypsin-like protease, and recombinant rhK7, a chymotrypsin-like protease. Both fragments inhibited rhK5 similarly in binding and kinetic studies performed at pH 8.0, as well as pH 5.0, the pH of the stratum corneum where both LEKTI and proteases may function. Inhibition equilibrium constants (Ki) measured either directly in concentration-dependent studies or calculated from measured association (kass) and dissociation (kdis) rate constants were 1.2-5.5 nM at pH 8.0 and 10-20 nM at pH 5.0. At pH 8.0, kass and kdis values were 4.7 x 10(5) M(-1) s(-1) and 5.5 x 10(-4) s(-1), and at pH 5.0 they were 4.0 x 10(4) M(-1) s(-1) and 4.3 x 10(-4) s(-1), respectively. The low Ki and kdis values (t1/2 of 20-25 min) indicate tight and specific association. Only fragment 6-9' was a good inhibitor of rhK7, demonstrating a Ki of 11 nM at pH 8.0 in a reaction that was rapidly reversible. These results show that LEKTI, at least in fragment form, is a potent inhibitor of rhK5 and that this protease may be a target of LEKTI in human skin.
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PMID:Inhibition of human kallikreins 5 and 7 by the serine protease inhibitor lympho-epithelial Kazal-type inhibitor (LEKTI). 1630 83

We report a 6-day-old Japanese girl showing generalized erythroderma accompanied by yellowish, exfoliative scaling that was accentuated on the face and scalp. Histological analysis showed psoriasiform dermatitis with acanthotic epidermis and premature shedding of the stratum corneum. Measurement of trypsin-like hydrolytic activity in SC showed six-fold greater activity compared with age-matched controls. DNA analysis revealed two mutations, 375delAT and 966insC, in exons 5 and 11, respectively, of the SPINK5 gene. Although at 4 weeks the child was still too young to display characteristic hair abnormalities or atopic diathesis, we diagnosed Netherton syndrome based on enzyme assay and DNA analysis.
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PMID:A case of a Japanese neonate with congenital ichthyosiform erythroderma diagnosed as Netherton syndrome. 1690 9

The multidomain proteinase inhibitor LEKTI (lympho-epithelial Kazal-type related inhibitor) consists of 15 potential serine proteinase inhibitory domains. In various diseases such as the severe skin disorder Netherton syndrome as well as atopy, defects in the gene encoding LEKTI have been identified that generate premature termination codons of translation, suggesting a specific role of the COOH-terminal part of LEKTI in healthy individuals. We overexpressed and purified a sequence comprising the 15th domain of LEKTI for further characterisation. Here, we present a high yield expression system for recombinant production and efficient purification of LEKTI domain 15 as a highly soluble protein with a uniform disulfide pattern that is identical to that of other known Kazal-type inhibitors. Also, the expected P1P1' site was confirmed. LEKTI domain 15 is a well-structured protein as verified by circular dichroism (CD) spectroscopy and a tight-binding and stable inhibitor of the serine proteinase trypsin. These findings confirm the designation of domain 15 as a proteinase inhibitor of the Kazal family.
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PMID:LEKTI domain 15 is a functional Kazal-type proteinase inhibitor. 1793 12

Netherton syndrome (NS) is a congenital ichthyosiform dermatosis caused by serine protease inhibitor Kazal-type 5 (SPINK5) mutations. Tissue kallikreins (KLKs) and lymphoepithelial Kazal-type-related inhibitor (LEKTI) (SPINK5 product) may contribute to the balance of serine proteases/inhibitors in skin and influence skin barrier function and desquamation. SPINK5 mutations, causing NS, lead to truncated LEKTI; each NS patient possesses LEKTI of a different length, depending on the location of mutations. This study aims to elucidate genotype/phenotype correlations in Japanese NS patients and to characterize the functions of each LEKTI domain. Since we were unable to demonstrate truncated proteins in tissue from patients with NS, we used recombinant protein to test the hypothesis that the length of LEKTI correlated with protease inhibitory activity. Genotype/phenotype correlations were observed with cutaneous severity, growth retardation, skin infection, stratum corneum (SC) protease activities, and KLK levels in the SC. Predominant inhibition by LEKTI domains against overall SC protease activities was trypsin-like (Phe-Ser-Arg-) activity by LEKTI domains 6-12, plasmin- and trypsin-like (Pro-Phe-Arg-) activities by domains 12-15, chymotrypsin-like activity by all domains, and furin-like activity by none. KLK levels were significantly elevated in the SC and serum of NS patients. These data link LEKTI domain deficiency and clinical manifestations in NS patients and pinpoints to possibilities for targeted therapeutic interventions.
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PMID:Correlation between SPINK5 gene mutations and clinical manifestations in Netherton syndrome patients. 1798 26

Kallikreins-related peptidases (KLKs) are serine proteases and have been implicated in the desquamation process of the skin. Their activity is tightly controlled by epidermal protease inhibitors like the lympho-epithelial Kazal-type inhibitor (LEKTI). Defects of the LEKTI-encoding gene serine protease inhibitor Kazal type (Spink)5 lead to the absence of LEKTI and result in the genodermatose Netherton syndrome, which mimics the common skin disease atopic dermatitis. Since many KLKs are expressed in human skin with KLK5 being considered as one of the most important KLKs in skin desquamation, we proposed that more inhibitors are present in human skin. Herein, we purified from human stratum corneum by HPLC techniques a new KLK5-inhibiting peptide encoded by a member of the Spink family, designated as Spink9 located on chromosome 5p33.1. This peptide is highly homologous to LEKTI and was termed LEKTI-2. Recombinant LEKTI-2 inhibited KLK5 but not KLK7, 14 or other serine proteases tested including trypsin, plasmin and thrombin. Spink9 mRNA expression was detected in human skin samples and in cultured keratinocytes. LEKTI-2 immune-expression was focally localized at the stratum granulosum and stratum corneum at palmar and plantar sites in close localization to KLK5. At sites of plantar hyperkeratosis, LEKTI-2 expression was increased. We suggest that LEKTI-2 contributes to the regulation of the desquamation process in human skin by specifically inhibiting KLK5.
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PMID:Identification of lympho-epithelial Kazal-type inhibitor 2 in human skin as a kallikrein-related peptidase 5-specific protease inhibitor. 1919 Jul 73


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