Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the presence of a membrane-permeable metal chelator, bovine adrenal cortex mitochondria imported P-450(SCC) precursor without processing of the amino-terminal extension peptide. The imported precursor was bound to the matrix side surface of the inner membrane. When the inhibition due to the metal chelator was removed, the imported precursor was processed to the mature form. Unprocessed precursor was also detected in mitochondria when the import reaction was carried out at relatively low temperature. These results suggest that the translocation of P-450(SCC) precursor across mitochondrial membranes is independent of its processing to the mature form. Both membrane-bound and solubilized P-450(SCC) could be cleaved by trypsin into two fragments with molecular weights of 29 kDa and 26 kDa, respectively, suggesting a two-domain structure of the molecule. The in vitro-imported and processed P-450(SCC) was also cleaved by trypsin in the same way. This finding indicated that the in vitro-imported and processed P-450(SCC) has the same conformation as the native form.
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PMID:Processing-independent in vitro translocation of cytochrome P-450(SCC) precursor across mitochondrial membranes. 381 79

Vast experience with cultivating biopsies from human tumors indicates that in most cases the admixture of fibroblasts has a negative effect on growth of tumor cells. Only rarely is observed help provided by the fibroblasts. It has also long been known that fibroblasts can inhibit by contact themselves and also produce growth factor(s) promoting cell proliferation. We have used three permanent squamous cell carcinoma lines and fibroblasts derived from biopsies of trachea to study this paradox. The inhibitory activity of fibroblasts is contact-dependent in a cell membrane-bound factor, which is trypsin sensitive. We prepared microsomal fractions (MF) from aged (more than 40 passages) fibroblasts and followed their effect on proliferation of the tumor cell lines in MTT assay. MF from all three fibroblast lines inhibited the tumor cells. Most regularly was this phenomenon observed with line UM-SCC 22B. Not all tumor cells are immortal. On the contrary, a large portion of them undergoes terminal differentiation. With the line UM-SCC 22B we tested the possibility that MF from fibroblasts can increase the portion of tumor cells which will senescence after few mitoses. The immortal cells were defined as cells capable in 8 or 13 days of forming colonies of more than 50 or 200 cells. The senescent cells were defined as cells not capable of producing within the same period of time colonies of more than 12 or 30 cells. The MF was able to increase the number of small colonies, i.e. the number of senescent tumor cells. The fibroblasts of the same passage level were releasing soluble growth factor(s) promoting growth of cells. Fibroblasts can apparently simultaneously inhibit growth by contact and release factor(s) promoting growth of cells. The final outcome is a result of the balance between these two forces. This balance is regulated by many intrinsic and extrinsic forces.
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PMID:Dual role of fibroblasts in tumor cell growth. 871 73

Our previous studies have demonstrated that myoepithelial cells, which surround incipient carcinomas in situ of the breast and other organs, exert antiinvasive and antiangiogenic effects in vitro through the elaboration of a number of different suppressor molecules among which include the shed membrane CD44. The present study addresses the mechanism of this myoepithelial CD44 shedding. This CD44 shedding is enhanced by PMA pretreatment, is specific for myoepithelial CD44, and inhibited by chymotrypsin-like inhibitors (chymostatin, alpha(1)-antichymotrypsin, TPCK, and SCCA-2) but not by trypsin-like inhibitors (TLCK), nor papain-like inhibitors (SCCA-1) nor hydroxamate-based or general metalloproteinase inhibitors (BB2516 (marimastat), 1,10-phenanthroline, and TIMP-1). The effect of PMA can be mimicked by exogenous chymotrypsin but not by other proteases. The CD44 shedding activity cannot be transferred by conditioned media, cell-cell contact, peripheral membrane, or integral membrane fractions. However, cell-free purified integral plasma membrane fractions obtained from myoepithelial cells pretreated with PMA also exhibit CD44 shedding which is inhibited by chymotrypsin-like inhibitors. These findings support the presence and activation of a putative chymotrypsin-like sheddase as the mechanism of CD44 shedding in myoepithelial cells.
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PMID:Myoepithelial-specific CD44 shedding is mediated by a putative chymotrypsin-like sheddase. 1111 26

Human matrix metalloproteinase-20 (MMP-20, enamelysin) fragments the enamel-specific protein amelogenin and has been shown to be synthesized exclusively by odontoblasts and ameloblasts and in certain odontogenic tumors. Here we demonstrate, for the first time, the expression of MMP-20 mRNA and protein in two carcinoma cell lines originating from the tongue. Treatment of the SCC-25 and HSC-3 cells with phorbol 12-myristate 13-acetate (10 nmol/L) up-regulated MMP-20 mRNA and protein expression by up to 1.6-fold, but transforming growth factor beta (10 ng/mL) had no effect. The latent proform of recombinant (r) human MMP-20 was converted by tumor-related trypsin-2. Activated rMMP-20 did not degrade type I or type II collagen, but efficiently hydrolyzed fibronectin, type IV collagen, laminin-1 and -5, tenascin-C, and beta-casein. This implies that MMP-20 not only participates in dental matrix remodeling but is also present in tongue carcinoma cells.
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PMID:Expression and regulation of MMP-20 in human tongue carcinoma cells. 1170 46

Remarkable progress has been made to identify genes expressed in squamous cell carcinomas of the head and neck (HNSCC). However, limited information is available on their corresponding protein products, whose expression, post-translational modifications, and activity are ultimately responsible for the malignant behavior of this tumor type. We have combined laser-capture microdissection (LCM) with liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify proteins expressed in histologically normal squamous epithelium and matching SCC. The protein fraction from approximately 10,000-15,000 normal and tumor cells was solubilized, digested with trypsin, and the resulting peptides were analyzed by LC-MS/MS. Database searching of the resulting sequence information identified 30-55 proteins per sample. Keratins were the most abundant proteins in both normal and tumor tissues. Among the proteins differentially expressed, keratin 13 was much lower in tumors, whereas heat-shock (Hsp) family members were highly expressed in neoplastic cells. Wnt-6 and Wnt-14 were identified in both normal and tumor tissues, respectively, and placental growth factor (PIGF) was detected only in tumors. Immunohistochemical analysis of HNSCC tissues revealed lack of keratin 13 in tumor tissues, and strong staining in normal epithelia, and high expression of Hsp90 in tumors. Our study, by combining LCM and proteomic technologies, underscores the advantages of this approach to investigate complex changes at the protein level in HNSCC, thus complementing existing and emerging genomic technologies. These efforts may likely result in the identification of new biomarkers for HNSCC that can be used to diagnose disease, predict susceptibility, and monitor progression in individual patients.
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PMID:Proteome-wide analysis of head and neck squamous cell carcinomas using laser-capture microdissection and tandem mass spectrometry. 1569 21

Nicotine, a pharmacologically active constituent of tobacco smoke, decreases sex steroid production and impairs reproductive function. The rate-limiting step in steroid hormone biosynthesis is the transport of substrate cholesterol from the outer to inner mitochondrial membrane by the steroidogenic acute regulatory protein (StAR). StAR is a 37 kDa cytoplasmic phosphoprotein processed as a 32 kDa intermediate to a mature 30 kDa inactive mitochondrial protein. StAR's cholesterol transport capacity is proportional to its residency time at the outer mitochondrial membrane (OMM). Nonsteroidogenic COS-1 cells transfected with StAR/F2, steroidogenic MA-10 cells induced with cAMP or transfected with StAR or the isolated steroidogenic mitochondria preincubated with nicotine reduced StAR expression, import and activity. Mitochondria isolated from steroidogenic tissues or cells, pretreated with nicotine, also reduced the association of StAR with the OMM, but had no effect on the import of signal sequence substituted SCC/N-62StAR. The fluorescence emission maximum of StAR was unchanged with nicotine, but StAR's free energy of unfolding and the surface area (m) increased in the presence of nicotine. Nicotine also blocked StAR from proteolysis with trypsin, suggesting that nicotine partially stabilised protein conformation by insertion into the molten globule conformation of StAR.
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PMID:Folding, activity and import of steroidogenic acute regulatory protein into mitochondria changed by nicotine exposure. 1760 86

Well-defined G-bands were obtained on somatic metaphase chromosomes of Encarsia berlesei using trypsin and warm 2x SCC in sequence. The G-banded pattern allowed rapid identification of all five metacentric chromosomes, which appeared uniformly lighted when stained with DAPI fluorochrome dye. It is stressed that ageing affects G-banding in this insect species; in fact, good banded chromosomes were obtained on 1-month air-stored chromosomes. Evidence for asynchronous condensation on the chromosomes of this species is also provided.
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PMID:Occurrence of G-banding in metaphase chromosomes of Encarsia berlesei (Hymenoptera: Aphelinidae). 1847 16

Mast cells (MCs) display a diversity of roles that may contribute to the stromal microenvironment alterations during tumor progression. The aim of this study was to investigate MC populations expressing tryptase and c-kit in lip squamous cell carcinoma (lip SCC) (n=37), actinic cheilitis (AC) (n=15) and normal lip mucosa (control) (n=6), as well as their relationship with microscopic parameters (collagen degeneration, elastin changes, angiogenesis and proliferative index). Tryptase, c-kit, CD31 and Ki-67 expressions were analyzed by means of immunohistochemistry and collagen and elastic fibers were visualized with Picrosirus and Verhoeff's stain, respectively. The numbers of tryptase+ MC were significantly higher in lip SCC when compared with control (P=0.01), while a similar density of these cells was observed in AC and lip SCC (P=0.09). The density of c-kit+ MC was similar in all groups examined (P=0.65). MC migration (c-kit+/Tryptase+ relationship) was 69% in lip SCC, 60% in AC and 100% in control. The number of CD31+ blood vessels was significantly higher in the lip SCC when compared with control and AC (P<0.01). The increase of MCs and angiogenesis in lip SCC may reflect an important modification in the tumor microenvironment during squamous photo-carcinogenesis.
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PMID:Density and migration of mast cells in lip squamous cell carcinoma and actinic cheilitis. 1922 48

Increased numbers of mast cells is a typical feature of a variety of human cancers. The major mediators in the secretory granules of the MC(TC) type of mast cells, serine proteinases tryptase and chymase, may be involved in squamous cell carcinoma (SCC) lesions by inducing matrix remodeling and epithelial cell detachment. The objective of this study was to analyze immunohistochemically whether MC(TC) mast cells as well as protease inhibitors, squamous cell carcinoma antigens (SCCAs), are present in the uterine cervical SCC. In addition, the effect of tryptase and chymase on uterine cervical SCC cell lines was studied in vitro. Here we report that tryptase- and chymase-positive mast cells are present in significant numbers in the peritumoral stroma of SCC lesions. Also, weak SCCA-2 immunoreactivity is observed in the SCC lesions, but only SCCA-1 in uterine cervical specimens with nonspecific inflammation. In cell cultures, especially chymase, but not tryptase, was shown to induce effective detachment of viable, growing and non-apoptotic SiHa SCC cells from substratum. Chymase also detached viable ME-180 SCC cells from substratum as well as degraded fibronectin. In contrast, normal keratinocytes underwent apoptotic cell death after similar prolonged chymase treatment. No inhibition of chymase was detected by SiHa cell sonicates nor did these cells express marked SCCA immunopositivity. MC(TC) mast cells containing tryptase and chymase are present in the peritumoral stroma of uterine cervical SCC and the malignant cells are only weakly immunoreactive for the chymase inhibitor SCCA-2. It is chymase that appears to be capable of inducing effective detachment of viable and growing SCC cells and therefore, it may release SCC cells from a tumor leading to spreading of malignant cells.
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PMID:Mast cell chymase is present in uterine cervical carcinoma and it detaches viable and growing cervical squamous carcinoma cells from substratum in vitro. 2127 49

There are several families of cysteine proteinases with different folds - for example the (chymo)trypsin fold family and papain-like fold family - but in both families the hydrolase activity of cysteine proteinases requires a cysteine residue as the catalytic nucleophile. In this work, we have analyzed the topology of the active site regions in 146 three-dimensional structures of proteins belonging to the Papain-like Cysteine Proteinase (PCP) superfamily, which includes papain as a typical representative of this protein superfamily. All analyzed enzymes contain a unique structurally closed conformation - a "PCP-Zone" - which can be divided into two groups, Class A and Class B. Eight structurally conserved amino acids of the PCP-Zone form a common Structural Core. The Structural Core, catalytic nucleophile, catalytic base and residue Xaa - which stabilizes the side-chain conformation of the catalytic base - make up a PCP Structural Catalytic Core (PCP-SCC). The PCP-SCC of Class A and Class B are divided into 5 and 2 types, respectively. Seven variants of the mutual arrangement of the amino-acid side chains of the catalytic triad - nucleophile, base and residue Xaa - within the same fold clearly demonstrate how enzymes with the papain-like fold adapt to the need to perform diverse functions in spite of their limited structural diversity. The roles of both the PCP-Zone of SARS-CoV-2-PLpro described in this study and the NBCZone of SARS-CoV-2-3CLpro presented in our earlier article (Denesyuk AI, Johnson MS, Salo-Ahen OMH, Uversky VN, Denessiouk K. Int J Biol Macromol. 2020;153:399-411) that are in contacts with inhibitors are discussed.
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PMID:Papain-like cysteine proteinase zone (PCP-zone) and PCP structural catalytic core (PCP-SCC) of enzymes with cysteine proteinase fold. 3305 70


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