Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.10.1 (ERK)
 95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We investigated whether staphylococcal exotoxins (SEs), in addition to their capacity to induce T-cell activation restricted by the T-cell receptor (TCR) beta-chain variable region, can deliver an activation signal to human T-cell clones through major histocompatibility complex (MHC) class II molecules. Eleven human T-cell clones (9 alpha beta TCR and 2 gamma delta TCR clones) of different antigenic specificities were tested for their capacity to proliferate in response to toxic shock syndrome toxin 1 (TSST-1) and two SEs, SEA and SEB. In the absence of accessory cells, only 4 alpha beta TCR clones were stimulated to proliferate, each by a single SE, and to mobilize intracellular free Ca2+ in response to that SE, events indicative of TCR engagement and, presumably, recognition restricted by the beta-chain variable region. In the presence of accessory cells, each of the 11 T-cell clones was stimulated to proliferate by any one of the three SEs tested. This apparently TCR-unrestricted SE-mediated polyclonal proliferation of T-cell clones occurred in the absence of an increase in intracellular free Ca2+ and was not dependent on the presence of MHC class II expression on accessory cells. In contrast, SE-mediated polyclonal proliferation did not occur in 3 alpha beta TCR clones derived from an MHC class II-deficient patient. Furthermore, all of the three SEs induced the proliferation of 4 natural-killer-cell clones, suggesting that expression of TCR/CD3 complex is not essential for SE-mediated polyclonal proliferation of activated lymphocytes. These results indicate that MHC class II molecules transduce activation signals to human T- and natural-killer-cell clones.
Proc Natl Acad Sci U S A 1991 Sep 01
PMID:Staphylococcal exotoxins deliver activation signals to human T-cell clones via major histocompatibility complex class II molecules. 188 94

The Escherichia coli arcA gene product regulates chromosomal gene expression in response to deprivation of oxygen (Arc function; Arc stands for aerobic respiration control) and is required for expression of the F plasmid DNA transfer (tra) genes (Sfr function; Sfr stands for sex factor regulation). Using appropriate lacZ fusions, we have examined the relationship between these two genetic regulatory functions. Arc function in vivo was measured by anaerobic repression of a chromosomal sdh-lacZ operon fusion (sdh stands for succinate dehydrogenase). Sfr function was measured by activation of a plasmid traY-lacZ gene fusion. An eight-codon insertion near the 5' terminus of arcA, designated arcA1, abolished Arc function, as previously reported by S. Iuchi and E.C.C. Lin (Proc. Natl. Acad. Sci. USA 85:1888-1892, 1988), but left Sfr function largely (greater than or equal to 60%) intact. Similarly, the arcB1 mutation, which depressed sdh expression and is thought to act by abolishing the signal input that elicits ArcA function, had little effect (less than or equal to 20%) on the Sfr function of the arcA+ gene product. Conversely, a valine-to-methionine mutation at codon 203 (the sfrA5 allele) essentially abolished Sfr activity without detectably altering Arc activity. These data indicate that Sfr and Arc functions are separately expressed and regulated properties of the same protein.
J Bacteriol 1991 Sep
PMID:Arc and Sfr functions of the Escherichia coli K-12 arcA gene product are genetically and physiologically separable. 188 42

Type IV collagen, a 500-kilodalton (alpha 1)2(alpha 2)1 heterotrimer with noncollagenous domains (NC1) is the major molecule in most basement membranes in the body. In addition to its structural role as scaffolding, type IV collagen is involved in promoting adhesion and migration of various cell types in vitro, including rabbit corneal epithelial cells. This study assessed the effect of purified proteolytic fragments of type IV collagen and selected synthetic peptides derived from the alpha 1 and alpha 2 chains that are related to the adhesion and directed migration of dissociated primary cultured rabbit epithelial cells. Two homologous peptides (HEP-1 and HEP-2) derived from alpha 1 and alpha 2 NC1 regions were found to promote epithelial cell adhesion. A peptide (HEP-3) derived from an interruption of the triple helix of type IV collagen was effective in promoting corneal epithelial cell migration in both chemotaxis and haptotaxis assays. The helical fragment of type IV collagen promoted both directed migration and ample adhesion, indicating that there may be at least another moiety in the helical region responsible for cell adhesion. The results with these peptides revealed to some extent how corneal epithelial cells react at the molecular level with type IV collagen. They could serve as the basis for therapeutic agents to modify corneal epithelial behavior in situations of perturbed wound healing.
Invest Ophthalmol Vis Sci 1991 Sep
PMID:Type IV collagen and corneal epithelial adhesion and migration. Effects of type IV collagen fragments and synthetic peptides on rabbit corneal epithelial cell adhesion and migration in vitro. 189 74

A search for the natural substrates for neutral endopeptidase (NEP; EC 3.4.24.11) in the immune system led to investigation of the enzyme's action on thymic humoral factor gamma 2 (THF). The ectoenzyme rapidly and efficiently hydrolyses the Lys6-Phe7 bond of the octapeptide. The site of cleavage was confirmed by h.p.l.c. analysis, amino acid analysis and sequence determination of the products. Phosphoramidon (3.6 microM), a potent inhibitor of the enzyme, prevents this cleavage even during prolonged incubation. The high efficiency of hydrolysis of THF by NEP is similar to that reported for [Leu5]enkephalin, and the dipeptide Phe-Leu is the C-terminal product in the hydrolysis of both peptides. The presence of NEP, reportedly identified as the common acute lymphoblastic leukaemia antigen (CALLA), in bone-marrow cells and other cells of the immune system raises the possibility that it may play a role in modulating the activity of peptides such as THF.
Biochem J 1991 Sep 15
PMID:Hydrolysis of thymic humoral factor gamma 2 by neutral endopeptidase (EC 3.4.24.11). 189 75

In this study, we tested the influence of i.p. Bowman-Birk protease inhibitor (BBI) administration on oncogene expression in unirradiated and irradiated rat colonic mucosa. Total cellular RNA was collected from the colonic mucosa, and the levels of c-myc, c-fos, c-Ha-ras, c-EGFR, and c-actin mRNA were examined by standard dot and Northern blot analyses. The data demonstrate that BBI is capable of preventing radiation-induced overexpression of c-myc and c-fos without interfering with the constitutive expression of these 2 genes. It was also determined that BBI did not interfere with either radiation-induced overexpression of c-Ha-ras and c-EGFR or the constitutive expression of c-Ha-ras, c-EGFR, or c-actin. The data demonstrate that the anticarcinogenic BBI selectively inhibits the overexpression of c-myc and c-fos while not affecting crypt cell proliferation. These results suggest that a protease is involved in the pathway for enhanced c-myc and c-fos expression and that protease inhibitors such as BBI can interrupt this pathway.
Cancer Res 1991 Sep 01
PMID:Effect of the Bowman-Birk protease inhibitor on the expression of oncogenes in the irradiated rat colon. 190 49

Staphylococcal enterotoxins are a family of structurally related proteins that are produced by Staphylococcus aureus. In addition to their role in the pathogenicity of food poisoning, these microbial superantigens have profound effects on the immune system, which makes them useful tools for understanding its mechanism of action. These molecules (24-30 kDa) are highly hydrophilic and exhibit low alpha helix and high beta pleated sheet content, suggesting a flexible, accessible structure. Staphylococcal enterotoxins are among the most potent activators of T lymphocytes known. The receptors for staphylococcal enterotoxins on antigen-presenting cells are major histocompatibility complex (MHC) class II molecules. Further, the alpha-helical regions of the class II molecule are essential for function and appear to interact directly with the NH2-terminal region of staphylococcal enterotoxins such as SEA. Recent studies have shown that a complex of staphylococcal enterotoxin and MHC class II molecules is required for binding to the V beta region of the T cell antigen receptor. Staphylococcal enterotoxin mitogenic activity is dependent on induction of interleukin 2, which may be intimately involved in the mechanism of toxicity. The mouse minor lymphocyte stimulating (M1s) "endogenous" self-superantigen has been shown to be a retroviral gene product, so this too is apparently a microbial superantigen. An understanding of the mechanisms of action of these microbial superantigens has implications for normal and pathological immune functions.
FASEB J 1991 Sep
PMID:Staphylococcal enterotoxin microbial superantigens. 191 93

The human c-MET oncogene encodes a transmembrane tyrosine kinase (p190c-met) with structural and functional features of a growth-factor receptor. Monoclonal antibodies (MAbs) have been used to investigate the distribution of the c-Met protein in human normal and neoplastic tissues. By immunofluorescence microscopy homogeneous expression was detected in normal hepatocytes as well as in epithelial cells lining the stomach, the small and the large intestine. Positive staining was also found in epithelial cells of the endometrium and ovary, and in basal keratinocytes of esophagus and skin. By Northern blot analysis, high levels of c-met messenger RNA were detected in specimens of liver, gastro-intestinal tract and kidney. c-met-specific mRNA was also found in thyroid, pancreas and placenta, in which organs c-Met protein was barely detectable by immunofluorescence. The antibodies revealed expression of c-MET protein in hepatomas (11/14), carcinomas of colon and rectum (19/21), stomach (11/22), kidney (16/19), ovary (9/17) and skin (7/17). Carcinomas of the lung (13/20), thyroid (11/13) and pancreas (5/7) were also positive. In these last cases (lung, thyroid and pancreas) tumor cells were homogeneously stained by the antibodies, whereas in their normal counterparts staining was barely detectable. These data suggest that the receptor encoded by c-MET plays a physiological role in epithelial cell growth and that its expression is altered in human carcinomas.
Int J Cancer 1991 Sep 30
PMID:The receptor encoded by the human c-MET oncogene is expressed in hepatocytes, epithelial cells and solid tumors. 191 29

Good exercise prescriptions provide work rates (WRs) that maintain heart rates (HR) in a target zone and at a percent of maximum metabolic equivalent (%METmax). HR and MET were evaluated from computer-controlled and set WR (constant speed) sessions (20 min at 65% METmax). Computer-controlled WR used a control algorithm to adjust speed and grade to maintain the target HR. The set WR (mean +/- S.D.) HR (139 +/- 8 bpm) was lower (p less than 0.05) than the target (147 +/- 3 bpm) and computer-controlled HRs (153 +/- 5 bpm). The set WR MET (8.6 +/- 2.2) was not different than the target (8.6 +/- 2.2), but both were lower than computer-controlled exercise (9.7 +/- 2.2). Computer-control time in target HR zone (16 +/- 5 min) was significantly (p less than 0.004) greater than set WR exercise (6 +/- 5 min). Computer-controlled WR was significantly better in maintaining target HR and the MET values were not physiologically different than target WRs.
Aviat Space Environ Med 1991 Sep
PMID:A comparison between computer-controlled and set work rate exercise based on target heart rate. 193 84

DNA contents of c-FMS and GM-CSF genes were analyzed by densitometer in nine patients with myelodysplastic syndrome or acute myeloid leukemia associated with abnormality of chromosome 5. Five patients with deletion in the long arm of chromosome 5 had loss of both c-FMS and GM-CSF genes. These findings suggest that c-FMS oncogene and GM-CSF gene locating in the critical region on chromosome 5 seem to have an important role in the process of leukemogenesis.
Rinsho Ketsueki 1991 Sep
PMID:[Parallel loss of c-FMS and GM-CSF genes in myeloid leukemias with 5q-chromosome]. 194 39

ONGC's Hazira Gas-Processing Complex (HGPC) consists of facilities for receiving natural gas along with associated condensate from an off-shore field at a rate of 20 MMN M3 per day. After separating the condensate, which is processed in condensate fractionation units, the gas is processed through various steps to recover LPG and to reduce its dew point to less than 5 degrees C in order to make it suitable for transportation over long distances. The acid gas recovered during the gas-sweetening step is processed to obtain sulphur. The major products manufactured at HGPC therefore are lean sweet gas, LPG, NGL, and sulphur. The Oil and Natural Gas Commission awarded the assignment on Hazard Study and Risk Analysis of their Hazira Gas-Processing Complex (HGPC) to the Council of Scientific and Industrial Research (CSIR) in association with the Netherlands Organisation for Applied Scientific Research (TNO). The scope of this assignment covered a number of closely related and fully defined activities normally encountered in this type of work. Identification of hazards through the most appropriate methods, assigning frequency of occurrence of major unwanted incidents, quantification and assessment of probable damage to plant equipment, environment, human and animal life due to an unexpected event, and evaluation of various methods for reducing risk, together constituted the methodology for this assignment. Detailed recommendations aimed at reducing risk and enhancing reliability of plant and machinery were made. This article gives an overview of the assignment.
Risk Anal 1991 Sep
PMID:Risk analysis of a gas-processing complex in India. 194 47


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