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:2.7.10.1 (ERK)
95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The protein encoded by the neu protooncogene (human gene symbol NGL for neuro/glioblastoma-derived) is a member of the surface receptor/tyrosine kinase family. Though its structure suggests that it can transduce a transmembrane signal, neither its extracellular ligand nor its critical intracellular substrates are known. To explore the functional properties of the protein encoded by neu, we created a fusion gene that joins the cytoplasmic domain of neu to the extracellular portion of an immunoglobulin heavy chain. The localization of the fusion polypeptide can then be controlled by coexpression with immunoglobulin light chain. In the absence of light chain, the heavy chain-neu polypeptide is expressed intracellularly and has no transforming activity. By contrast, in the presence of light chain the fusion polypeptide is expressed at the cell surface and produces tumorigenic foci. Thus, transformation apparently requires expression at the cell surface, where the neu intracellular domain can interact with components that are localized to the plasma membrane. The fusion protein is active in cellular transformation when the transmembrane domain is derived either from neu or from immunoglobulin, indicating that the neu transmembrane domain is not specifically required for transformation, although neu activation in tumors is known to result from a point mutation in this region. The extracellular immunoglobulin heavy and light chain domains of the fusion protein form a functional binding site that allows antigen to modulate its activity, reversing the transforming effect.
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PMID:neu protooncogene fused to an immunoglobulin heavy chain gene requires immunoglobulin light chain for cell surface expression and oncogenic transformation. 290

An Epstein-Barr virus (EBV) deletion mutant, HR-1, cannot immortalize lymphocytes. HR-1 was derived from a virus strain, Jijoye, that is immortalization competent. Using human antiserum from certain patients with chronic active EBV infection, we have identified in Jijoye cells a protein of apparent mass of 78-80 kDa that is missing in cells with the HR-1 genome. A protein of identical size and antigenicity has been stably expressed in mouse LTK- cells by gene transfer with cloned Jijoye EBV DNA that encompasses the deletion in the HR-1 genome. The expressed product is a nuclear neoantigen. The polypeptide we have identified is likely to be essential in the immortalization process.
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PMID:Identification and expression of a nuclear antigen from the genomic region of the Jijoye strain of Epstein-Barr virus that is missing in its nonimmortalizing deletion mutant, P3HR-1. 299 90

We have constructed two recombinant plasmid vectors for direct expression and amplification of cDNA in mammalian cells. Each vector carries two dominant selectable markers (the bacterial neo gene and the mouse DHFR gene), a promoter sequence (viral LTR in pAV009/A+, and sheep metallothionein promoter in pMT010/A+), a polyadenylation signal sequence, and a Bam HI site to allow insertion of cDNA. We have used these vectors to prepare recombinant clones for the expression of rat phenylalanine hydroxylase (PH) in LTK- cells. Selection of transformants with neomycin followed by selection of the transformants in methotrexate led to a 30- to 60-fold amplification of the DHFR marker and co-amplification of the PH cDNA, with a corresponding increase in the level of PH mRNA and enzyme polypeptide. The expressed enzyme has a subunit molecular weight of 50,000 which corresponds to the W- allele of rat liver PH. PH activity was detected in the transfected cells by enzymatic measurement of the conversion of [14C]phenylalanine to [14C]tyrosine, and by growth of these cells in a tyrosine-free culture medium. Expression of rat PH in cell culture should facilitate the analysis of the biochemical properties of this enzyme.
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PMID:Vectors for expression and amplification of cDNA in mammalian cells: expression of rat phenylalanine hydroxylase. 302 40

Herpes simplex viruses encode a structural protein which induces, in trans, expression of alpha genes, the first set of genes to be expressed after infection of permissive cells. This protein, designated as the alpha-trans-inducing factor (alpha-TIF), maps within the BamHI F fragment, and its gene has been sequenced. In the course of mapping the domain of the alpha-TIF gene, it was noted that the intact BamHI fragment was consistently more effective than the complete domain of the alpha-TIF gene in inducing expression of alpha genes. Cotransfections of DNA fragments containing an alpha indicator gene and the alpha-TIF gene with various regions of the BamHI F DNA fragment revealed that the sequences located 3' to the alpha-TIF gene raised the activity of the alpha-TIF gene to nearly the same level as that of the intact BamHI F fragment. The nucleotide sequence and S1 nuclease mapping analyses revealed the presence of two transcribed open reading frames capable of encoding polypeptides with translated molecular weights of 77,357 and 70,527. To determine whether the effect of these sequences in trans on alpha-TIF-mediated induction of alpha genes was due to expression of these genes or competition for transcriptional factors, we constructed plasmids that contained both genes. Into each or both of these genes we inserted, near the translation initiation sites, 14-base-pair linkers carrying translational stop codons (TAG) in all three reading frames. Analyses of these plasmids indicated that the gene encoding the 70,527-molecular-weight polypeptide reduced alpha-TIF-dependent induction of alpha genes, whereas the gene encoding the 77,357-molecular-weight polypeptide increased this activity. Insertion of the stop codons abolished these activities.
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PMID:Characterization and nucleotide sequence of two herpes simplex virus 1 genes whose products modulate alpha-trans-inducing factor-dependent activation of alpha genes. 302 33

An allele of the Prot locus, which encodes a major globulin of the maize scutellum, is a variant for a site of protein processing. Segregation analysis and recombination mapping indicate that the variant is an allele of the Prot locus. Designated Prot-V, this allele specifies three polypeptides, V1, V2, and V3. The V1 polypeptide is incompletely processed during the proteolytic processing step catalyzed by the product of the Mep locus. Cyanogen bromide cleavage studies support the precursor-product relationship between V1 and V2. The V1 product is shortened with respect to other PROT' proteins and it is postulated that the normal site of MEP processing has been removed by this foreshortening.
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PMID:An allele of the Prot locus in maize is a variant for the site of protein processing. 322 47

The mammalian cytosolic thymidine kinase is one of a number of enzymes involved in DNA replication whose activities increase dramatically during S phase of the cell cycle. As a first step in defining the mechanisms that control the S phase induction of thymidine kinase activity, we have purified the human enzyme from HeLa cells and raised a specific immune serum against the purified protein. The enzyme was isolated from cells arrested in S phase by treatment with methotrexate and purified to near homogeneity by ion-exchange and affinity chromatography. Stabilization of the purified enzyme was achieved by the addition of digitonin. An electrophoretic Rm of 0.2 in nondenaturing gels characterizes the purified enzyme activity as cytosolic thymidine kinase. The enzyme has a Stoke's radius of 40 A determined by gel filtration and a sedimentation coefficient of 5.5 S determined by glycerol gradient sedimentation. Based on these hydrodynamic values, a native molecular weight of 96,000 was calculated for the purified enzyme. When electrophoresed in denaturing sodium dodecyl sulfate-polyacrylamide gels under reducing conditions, the most purified enzyme fraction was found to contain one predominant polypeptide of Mr = 24,000. Several lines of evidence indicate that this polypeptide is responsible for thymidine kinase enzymatic activity. 1) The Mr = 24,000 polypeptide co-migrates with thymidine kinase activity in electrophoretic and sedimentation analyses. 2) A subunit Mr = 25,504 is predicted by the nucleotide sequence of a recently isolated cDNA clone that encodes HeLa thymidine kinase. 3) Mouse LTK- cells transformed with this clone express a cytosolic thymidine kinase activity, as well as a novel Mr = 24,000 polypeptide detectable with immune serum raised against the purified human enzyme.
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PMID:Human cytosolic thymidine kinase. Purification and physical characterization of the enzyme from HeLa cells. 333 3

The HER2/neu protooncogene was found to be amplified in 6 of 109 primary adenocarcinoma tumors. No HER2/neu amplification was found in 29 other primary nonadenocarcinomatous tumors. In two colon tumors, in addition to the amplification, DNA rearrangement of HER2/neu gene was also observed. The rearrangement was explored in detail in one tumor and it was shown to be confined to the 3' region of the gene. Moreover, this tumor expressed an aberrant HER2/neu polypeptide with a molecular weight of 190,000, which is larger by approximately 5,000 than the molecular weight of the normal HER2/neu protein. The aberrant HER2/neu protein was immunoprecipitated with site-specific antibodies against a synthetic peptide from the COOH-terminal end of the normal HER2/neu protein; it also displayed intrinsic protein tyrosine kinase activity leading to self-phosphorylation.
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PMID:Sporadic amplification of the HER2/neu protooncogene in adenocarcinomas of various tissues. 334 25

It is established that the part of the SEA and SEC2 polypeptide chain responsible for the binding of these toxin proteins with the membrane receptor on the surface of rabbit thymocytes and mitogenic effect is localised in the NH2-terminal region of the molecule. The SEC2 splits in two fragments T1 (17 kdalton) and T2 (12.5 kdalton) under limited proteolysis by trypsin in the presence of 2-ME. The amino acid terminal residues of SEA, SEC2 and their proteolytic fragments are also studied.
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PMID:NH2-terminal localization of that part of the staphylococcal enterotoxins polypeptide chain responsible for binding with membrane receptor and mitogenic effect. 348 88

The C-terminal eight-amino acid derivative of CCK, sulfated on the tyrosine residue (CCK8S), stimulated a dose-dependent biphasic pattern of insulin secretion from isolated perifused islets in the presence of 7 mM glucose. It was without any effect if glucose were absent from the medium or maintained at 4 mM. The response to CCK8S was readily reversible and dependent on the presence of extracellular calcium. While CCK8S did not increase glucose usage rates above those noted with 7 mM glucose alone, inclusion of the metabolic inhibitor 2-deoxyglucose lowered glucose usage rates to values obtained with 3-5 mM glucose and abolished the influence of CCK8S on insulin output. Removal of the metabolic inhibitor restored the secretory response. N-Acetylglucosamine (15 mM) or glyceraldehyde (2.5 mM) substituted for glucose and permitted CCK8S to evoke secretion. The nonsulfated eight-amino acid derivative of CCK, CCK8, provoked insulin secretion in the presence of 7 mM glucose, but only at 10-100 times greater levels than CCK8S. CCK4 (1 microM) did not influence insulin output in the presence of 7 mM glucose. On an equimolar basis, CCK8S was significantly more effective than gastric inhibiting polypeptide in augmenting insulin output. The results support a role for CCK8S in the regulation of insulin levels in vivo.
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PMID:Influence of cholecystokinin on insulin output from isolated perifused pancreatic islets. 352 23

The 0.5 M KCl-treatment solubilizes the outer arms from sea urchin sperm axonemes. Approximately 30 percent of A-polypeptide, corresponding to dynein 1 in SDS- polyacrylamide gel, was solubilized by this treatment (as SEA-dynein 1). Electron microscopic observation indicated that the extracted axonemes lacked the outer arms in various degrees. The DEA-dynein 1 was that the extracted axonemes lacked the outer arms in various degrees. The SEA-dyenin 1 was purified and an antiserum against it was prepared in rabbits. The specificity of antiserum to dynein 1 was determined by immunoelectrophoresis and ouchterlony's double-diffusion test. The anti-dynein 1 serum inhibited ATPase activity of purified SEA-dynein 1 by 95 percent. By the indirect peroxidase-conjugated antibody method, the loci of SEA-dynein 1 within the intact, salt- extracted and mechanically disrupted axonemes were determined to be the outer arms: deposition of electron-dense materials which represents their localization was detected at the distal ends of the outer arms, in the case of intact axonemes. The 5-6 cross- bridge was hardly decorated. No decoration was seen in the salt-extracted axonemes lacking all the outer arms. In disrupted axonemes, which consist of single to several peripheral doublets, electron-dense materials were deposited only on the outer arms. Approximately 73 percent of axonemal ATPase activity sensitive to antiserum was solubilized by repeated salt-extractions. One-half of A-polypeptide (SEA-dynein 1 located at the outer arms) was contained in the pooled extracts. The extracted axonemes contained another half of A-polypeptide (SUA-dynein 1 supposed to locate at the inner arms) and retained 31 percent of axonemal ATPase activity that was almost resistant to antiserum. Solubilized SUA-dynein 1 was immunologically the same as SEA-dynein 1. This result indicates that in situ SUA-dynein 1 did not receive anti-dynein 1 antibodies, coinciding with the result obtained for salt-extracted axonemes lacking all the outer arms by the enzyme-antibody method mentioned above. These observations suggest that immunological dissimilarity in dynein 1 between outer and inner arms but do not tell us that the inner arms do not contain dynein 1.
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PMID:Immunological dissimilarity in protein component (dynein 1) between outer and inner arms within sea urchin sperm axonemes. 617 2


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