Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04155 (pS2)
 1,234 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The preparation and purification of recombinant mature pNR-2/pS2, a single-domain member of the 'trefoil' family of cysteine-rich secreted proteins, is described. Analysis of recombinant pNR-2/pS2 by ion-exchange chromatography showed that it was heterogeneous. The heterogeneity was reduced by treatment with thiol-group-containing reagents, suggesting that it is caused by the odd number of cysteine residues in mature pNR-2/pS2, and this view was reinforced by mutation of the extra-trefoil domain cysteine residue, Cys58, to a serine residue. Electrophoresis of recombinant pNR-2/pS2 Cys58 and pNR-2/pS2 Ser58 proteins under non-denaturing conditions confirmed that the Ser58 mutant is much more homogeneous, and showed that most of pNR-2/pS2 Ser58 co-migrates as a single band with pNR-2/pS2 secreted from breast-cancer cells in culture. Treatment of recombinant pNR-2/pS2 proteins with various thiol-group-reactive reagents indicated that cysteine is the most effective at producing recombinant pNR-2/pS2 that co-migrates with pNR-2/pS2 secreted by breast-cancer cells. Dithiothreitol appeared to denature the proteins, and GSH was relatively ineffective. pNR-2/pS2 Cys58 treated with cysteine and untreated pNR-2/pS2 Ser58 had the same apparent molecular mass, measured by gel filtration, as pNR-2/pS2 secreted from breast-cancer cells. This is the first report of the production of a recombinant mature single-domain trefoil peptide and should greatly facilitate elucidation of the structure and function of pNR-2/pS2.
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PMID:Production and comparison of mature single-domain 'trefoil' peptides pNR-2/pS2 Cys58 and pNR-2/pS2 Ser58. 894 62

pNR-2/pS2 is a 60 residue extracellular protein, which was originally discovered in human breast cancer cells, and subsequently found in other tumours and normal gastric epithelial cells. We have determined the three-dimensional solution structure of a C58S mutant of human pNR-2/pS2 using 639 distance and 137 torsion angle constraints obtained from analysis of multidimensional NMR spectra. A series of simulated annealing calculations resulted in the unambiguous determination of the protein's disulphide bonding pattern and produced a family of 19 structures consistent with the constraints. The peptide contains a single "trefoil" sequence motif, a region of about 40 residues with a characteristic sequence pattern, which has been found, either singly or as a repeat, in about a dozen extracellular proteins. The trefoil domain contains three disulphide bonds, whose 1-5, 2-4 and 3-6 cysteine pairings form the structure into three closely packed loops with only a small amount of secondary structure, which consists of a short alpha-helix packed against a two-stranded antiparallel beta-sheet. The structure of the domain is very similar to those of the two trefoil domains that occur in porcine spasmolytic polypeptide (PSP), the only member of the trefoil family whose three-dimensional structure has been previously determined. Outside the trefoil domain, which forms the compact "head" of the molecule, the N and C-terminal strands are closely associated, forming an extended "tail", which has some beta-sheet character for part of its length and which becomes more disordered towards the termini as indicated by (15)N{(1)H} NOEs. We have considered the structural implications of the possible formation of a native C58-C58 disulphide-bonded homodimer. Comparison of the surface features of pNR-2/pS2 and PSP, and consideration of the sequences of the other human trefoil domains in the light of these structures, illuminates the possible role of specific residues in ligand/receptor binding.
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PMID:High-resolution solution structure of human pNR-2/pS2: a single trefoil motif protein. 909 35

The single-domain human trefoil proteins [pNR-2/pS2 and human intestinal trefoil factor (hITF)] have seven cysteine residues, of which six are involved in maintaining the structure of the trefoil domain. The seventh does not form part of the trefoil domain and is located three residues from the C-terminus. The ability of the pNR-2/pS2 single trefoil domain protein to dimerize was examined by using recombinant protein with either a cysteine or a serine residue at this position by equilibrium ultracentrifugation, laser-assisted desorption MS, gel filtration and PAGE. pNR-2/pS2 Cys58 formed dimers, whereas pNR-2/pS2 Ser58 did not. Experiments in which the dimer was treated with thiol agents demonstrated that the dimer was linked via a disulphide bond and that the intermolecular disulphide bond was more susceptible to reduction than the intramolecular disulphide bonds. To examine whether dimeric pNR-2/pS2 was secreted by oestrogen-responsive breast cancer cells, which are known to express pNR-2/pS2 mRNA, conditioned medium was separated on non-denaturing polyacrylamide gels, transferred to PVDF membrane and reacted with antiserum against pNR-2/pS2. Monomeric and dimeric pNR-2/pS2 were detected but the majority of the protein reactivity was associated with a larger protein. Treatment of this protein with thiol agents suggested that it is an oligomer containing pNR-2/pS2 linked to another protein by a disulphide bond. These studies suggest that the biological action of pNR-2/pS2 single-domain trefoil protein might involve the formation of homodimers or oligomers with other proteins.
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PMID:Homodimerization and hetero-oligomerization of the single-domain trefoil protein pNR-2/pS2 through cysteine 58. 935 42

The unique structure in which six cysteine residues in a sequence of 38 or 39 amino acid residues form three disulphide bonds in a 1-5, 2-4 and 3-6 configuration constitutes the basic elements of a trefoil domain. Today three mammalian trefoil factors (TFF1, TFF2 and TFF3) containing one or two trefoil domains are known. Trefoil factors are usually associated with the mucin layer of the gastrointestinal tract. Early studies on trefoil factors concentrated on structure elucidation and sites of expression in health and disease, whereas studies over the last 3-5 years have focused on the mechanism of action and the search for specific receptors. This review summarises our present knowledge of trefoil peptide structures, their sites of expression, and their protection and repair functions, with a focus on the mechanism by which these peptides exert their biological function.
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PMID:Trefoil peptides: from structure to function. 944 40

The "TFF domain" is an ancient cysteine-rich shuffled module forming the basic unit for the family of secretory TFF peptides (formerly P-domain peptides and trefoil factors). It is also an integral component of mosaic proteins associated with mucous surfaces. Three mammalian TFF peptides are known (i.e., TFF1-TFF3); however, in Xenopus laevis the pattern is more complex (xP1, xP4.1, xP4.2, and xP2). TFF peptides are typical secretory products of a variety of mucin-producing epithelial cells (e.g., the conjunctiva, the salivary glands, the gastrointestinal tract, the respiratory tract, and the uterus). Each TFF peptide shows an unique expression pattern and different mucin-producing cells are characterized by their specific TFF peptide/secretory mucin combinations. TFF peptides have a pivotal role in maintaining the surface integrity of mucous epithelia in vivo. They are typical constituents of mucus gels, they modulate rapid mucosal repair ("restitution") by their motogenic and their cell scattering activity, they have antiapoptotic effects, and they probably modulate inflammatory processes. Pathological expression of TFF peptides occurs as a result of chronic inflammatory diseases or certain tumors. TFF peptides are also found in the central nervous system, at least in mammals. In particular, TFF3 is synthesized from oxytocinergic neurons of the hypothalamus and is released from the posterior pituitary into the bloodstream.
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PMID:Cell type specific expression of secretory TFF peptides: colocalization with mucins and synthesis in the brain. 1183 92

The molecular pathology of precursor lesions leading to invasive pancreatic ductal adenocarcinomas remains relatively unknown. We have applied cDNA microarray analysis to characterize gene expression profiles in a series of intraductal papillary-mucinous tumors (IPMTs) of the pancreas, which represents one of the alternative routes of intraepithelial progression to full malignancy in the pancreatic duct system. Using a cDNA microarray containing 4992 human genes, we screened a total of 13 IPMTs including nine noninvasive and four invasive cases. Expression change in more than half of the tumors was observed for 120 genes, ie, 62 up-regulated and 58 down-regulated genes. Some of the up-regulated genes in this study have been previously described in classical pancreatic carcinomas such as lipocalin 2, galectin 3, claudin 4, and cathepsin E. The most highly up-regulated genes in IPMTs corresponded to three members of the trefoil factor family (TFF1, TFF2, and TFF3). Immunohistochemistry performed on five genes found to be differentially expressed at the RNA level (TFF1, TFF2, TFF3, lipocalin 2, and galectin 3) showed a good concordance between transcript level and protein abundance, except for TFF2. Hierarchical clustering organized the cases according to the dysplastic and invasive phenotype of theIPMTs. This analysis has permitted us to implicate several genes (caveolin 1, glypican 1, growth arrest-specific 6 protein, cysteine-rich angiogenic inducer 61) in tumor progression. The observation that several genes are differentially expressed both in IPMTs and pancreatic carcinomas suggests that they may be involved at an early stage of pancreatic carcinogenesis.
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PMID:Characterization of gene expression profiles in intraductal papillary-mucinous tumors of the pancreas. 1627 14

Gp-340 is a glycoprotein belonging to the scavenger receptor cysteine rich (SRCR) group B family. It binds to host immune components such as lung surfactant protein D (SP-D). Recent studies found that gp-340 interacts directly with pathogenic microorganisms and induces their aggregation, suggesting its involvement in innate immunity. In order to investigate further its potential immune functions in the appropriate cell lines, the expression of gp-340 in four conventional immune cell lines (U937, HL60, Jurkat, Raji), and two innate immune-related epithelial cell lines (A549 derived from lung and AGS from stomach), was examined by RT-PCR and immunohistochemistry. The resting immune cell lines showed weak or no gp-340 mRNA expression; while the two epithelial cell lines expressed gp-340 at much higher level, which was differentially regulated by phorbol myristate acetate (PMA) treatment. In the A549 cells, gp-340 was up-regulated along with the PMA-induced proinflammatory expression of both IL-6 and IL-8. In AGS cells, PMA down-regulation of gp-340 was seen in parallel with an up-regulation of the two mature gastric epithelial specific proteins TFF1 (trefoil factor 1) and TFF2, which are implicated as markers of terminal differentiation. Analysis of the distribution of gp-340, together with the TFFs and SP-D in normal lung and gastric mucosa, supported further our in vitro data. We conclude that the differential regulation of gp-340 in the two epithelial cell lines by PMA indicates that gp-340 s involvement in mucosal defence and growth of epithelial cells may vary at different body locations and during different stages of epithelial differentiation.
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PMID:The scavenger receptor, cysteine-rich domain-containing molecule gp-340 is differentially regulated in epithelial cell lines by phorbol ester. 1245 35

The human trefoil proteins TFF1 and TFF3 are expressed predominantly in the gastrointestinal tract. They are also expressed and regulated by estrogens in malignant breast epithelial cells. TFF1 and TFF3 are small cysteine-rich acidic secreted proteins of 60 and 59 amino acids with similar isoelectric points of 4.75 and 3.94, respectively. Each contains one trefoil domain that is characterized by several conserved features including six cysteine residues with conserved spacing. TFF1 and TFF3 form intermolecular disulfide bonds via an extra-trefoil domain cysteine residue and are present in vivo as monomers and homodimers and as complexes with other proteins. The TFF1 dimer is more active than the TFF1 monomer. In the present study the hydrodynamic and charge properties of TFF1 and TFF3 monomers and homodimers have been compared and shown to differ markedly. Notably, TFF1 is significantly more asymmetric than TFF3 (frictional coefficients 1.25 and 1.12, respectively, p < 0.001), and homodimerization of TFF1 results in a greater increase in asymmetry than for TFF3. The overall charges of TFF1 and TFF3 are very different at neutral pH. Titration curves predicted significant differences in charge across a wide pH range that agreed well with experimental data. The locations of charged amino acids in the primary sequences and in the tertiary structures of TFF1 and TFF3 were examined. This revealed interesting divergence in both the distribution and local topology of charged amino acid side chains. The significant differences between the shape, size, and surface charge of these two closely related molecules may account for their divergent biological activities.
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PMID:The closely related estrogen-regulated trefoil proteins TFF1 and TFF3 have markedly different hydrodynamic properties, overall charge, and distribution of surface charge. 1284 74

TFF1 is one of three human trefoil proteins expressed principally in the gastrointestinal tract in normal tissues. TFF1 protects the gastric mucosa against damage as a result of its ability to facilitate reconstitution of damaged gastric mucosa and its involvement in the secretion and structure of gastric mucus. The most biologically active molecular form in cell culture and animal models tested is a dimer formed by a disulfide bond between two cysteine residues close to the C terminus of the protein. We have therefore developed an assay for this form of TFF1 which should facilitate its measurement in biological samples.
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PMID:Development of a two-site ELISA assay for the dimeric form of human TFF1. 1517 66

The present review will include the mammalian trefoil factors, TFF1, TFF2 and TFF3. It will summarise the amino acid sequences from different species, their posttranslational modifications and their structures determined by X-ray analysis and nuclear magnetic resonance studies. Trefoil factors all have a well-defined, structurally conserved trefoil domain. The trefoil domain consists of 42 or 43 amino acid residues and contains 6 cysteine residues that form disulphide bonds in a 1-5, 2-4 and 3-6 configuration. By the establishment of an additional intra-molecular disulphide bond at the C-terminal end, TFF1 and TFF3 form homodimers or heterodimers. This dimer formation of TFF1 and TFF3 will be discussed, and the possible implications for biological activity will be reviewed. The physicochemical characteristics including protease stability of trefoil factors will be summarised. The biological implications of different molecular forms of trefoil factors and their interaction with mucins will be discussed together with other functional insights.
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PMID:Structure of mammalian trefoil factors and functional insights. 1637 84


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