Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Oncornaviruses, which contain a virion-associated protein kinase, were found to possess phosphoproteins as virion structural components. One major phosphoprotein common to strains of laboratory and wild mouse oncornaviruses and a strain of feline leukemia virus was shown to be a polypeptide of about 12, 000 mol wt. In addition to this, the Kirsten strain of murine sarcoma virus contained a second major phosphoprotein of about 10, 000 mol wt, and mouse erythroblastosis virus contained a second major phosphoprotein that was either identical to or comigrated with the virion glycoprotein of about 74, 000 mol wt. The major phosphoprotein of RD-114 virus was found to be of about 16, 000 mol wt. The major phosphoamino acid of the 12, 000-mol wt polypeptide of the mouse erythroblastosis virus was identified as phosphoserine, and that of the 16, 000-mol wt polypeptide of the RD-114 virus was identified as phosphothreonine.
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PMID:Phosphoproteins: structural components of oncornaviruses. 16 71

The sequence relations between Kirsten murine sarcoma virus (Ki-SV), Harvey murine sarcoma virus (Ha-SV), and a rat endogenous 30S RNA were studied by electron microscope heteroduplex analysis. The sequence relationships between the sarcoma viruses and their respective parental murine leukemia viruses (Kirsten and Moloney murine leukemia viruses), as well as between the two murine leukemia viruses, were also studied. The only observed nonhomology feature of the Kirsten murine leukemia virus/Moloney murine leukemia virus heteroduplexes was a substitution loop with two arms of equal length extending from 1.80 +/- 0.18 kilobases (kb) to 2.65 +/- 0.27 kb from the 3' end of the RNA. It is believed that this feature lies in the env gene region of the viral genomes. The Ha-SV and Moloney murine leukemia virus genomes (respective lengths, 6.0 and 9.0 kb) were homologous in a 1.0 +/- 0.05-kb region at the 3' end and possibly over a 200-nucleotide region at the 5' ends; otherwise, they were nonhomologous. Ha-SV and Ki-SV (length, 7.5 kb) were homologous in the first 4.36 +/- 0.37-kb region from the 3' end and in a 0.70 +/- 0.15-kb region at the 5' end. In between, there was a nonhomology region, possibly containing a short (0.23-kb) region of partial or total homology. The heteroduplex analysis between rat endogenous 30S RNA and Ki-SV shows that there are mixed regions of sequence homology and nonhomology at both the 5' and 3' ends. However, there is a large (4-kb) region of homology between Ki-SV and the rat 30S RNA in the center of the genomes, with only a small nonhomology hairpin feature. These studies help to define the regions of homology between the Ha-SV and Ki-SV genomes with each other and with the rat endogenous 30S RNA. These regions may be related to the sarcoma genicity of the viruses. In particular, the 0.7-kb region of homology of Ha-SV with Ki-SV at the 5' ends may be related to the formation of a 21,000-dalton phosphoprotein in cells transformed by either virus.
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PMID:Heteroduplex analysis of the sequence relationships between the genomes of Kirsten and Harvey sarcoma viruses, their respective parental murine leukemia viruses, and the rat endogenous 30S RNA. 22 50

The purified p12 phosphoprotein of Rauscher murine leukemia virus was fractionated by ion exchange chromatography into subpopulations of molecules containing different amounts of covalently linked phosphate. Of the various phosphorylated forms of p12 protein purified from virions, only a species containing relatively little phosphate can bind in vitro to purified homologous 70S viral RNA. Using ultraviolet irradiation to stabilize ribonucleoprotein complexes in intact virions, the same molecular species of p12 phosphoprotein can be isolated in close association with the 70S viral genome. The results show that phosphorylation of type C viral p12 proteins influences the extent, but not the specificity, of their interaction with homologous viral RNA.
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PMID:Phosphorylation of murine type C viral p12 proteins regulates their extent of binding to the homologous viral RNA. 84 4

Rauscher murine leukemia virus glycoprotein gp69/71 and non-glycosylated p15(E) are synthesized by way of a 90,000-dalton precursor glycoprotein, termed Pr2a+b. Peptide mapping experiments showed that Pr2a+b contains all the tyrosine-containing tryptic peptides of gp69/71. Two additional tyrosine-containing tryptic peptides in Pr2a+b that are not detected in gp69/71 are found in p15(E). Thus, gp69/71 and p15(E) peptide sequences account for all the tyrosine tryptic peptides of Pr2a+b. The gene order of the two proteins was determined by pulse-labeling infected cells in the presence and absence of pactamycin at concentrations of the inhibitor that prevent initiation of translation, but not elongation. The gene order was found to be: (2)HN-gp69/71-p15(E)-COOH. A newly identified major viral protein, termed p12(E), migrates in sodium dodecyl sulfate-polyacrylamide gels in the "p12" region. It is related to p15(E) as determined by tryptic mapping experiments. p15(E) and p12(E) are not phosphorylated, and both can be separated from phosphoprotein p12 by guanidine hydrochloride-agarose chromatography. p12(E) and p15(E) elute in the void volume fraction, whereas phosphoprotein p12 elutes between p15 and p10. The two p12 proteins can also be separated from each other by two-dimensional gel electrophoresis involving isoelectric focusing in the first dimension and sodium dodecyl sulfate-gel electrophoresis in the second dimension.
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PMID:Common precursor for Rauscher leukemia virus gp69/71, p15(E), and p12(E). 89 95

Monoclonal antibodies allowed recognition and identification of a series of hematopoietic cell membrane antigens expressed on plasma membranes of leukemia patients and on cells of healthy subjects. Monoclonal antibodies produced in different laboratories were clustered on the basis of their reactivity with normal and malignant hematopoietic cells into CD (cluster of differentiation) groups, with defined properties of recognized antigens (glycoprotein, phosphoprotein or glycolipid nature, molecular weight, isoelectric point, amino acid or carbohydrate sequence, etc.) and with functional characteristics of the corresponding antigen and its distribution on cells of the hematopoietic system. This "CD system" of human hematopoietic cell differentiation antigens was established in a series of international laboratory workshops (1982-1989). The present state of the CD classification system, as assessed after the IVth International Workshop on Hematopoietic Cell Differentiation Antigens (1988/89), in which more than 100 laboratories analyzed over 1,000 monoclonal antibodies, is described. An overview of the data concerning properties of monoclonal antibodies produced in the authors' laboratory (monoclonal antibodies series Bra-) is presented.
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PMID:[Differentiation antigens of hematopoietic cells (CD system)]. 128 18

Rex protein, the posttranscriptional regulator of human T-cell leukemia virus type I (HTLV-I), is required for the control of viral structural protein expression and virus replication. Rex is a phosphoprotein found predominantly in the cell nucleolus, whose function is thought to be regulated by its nucleolar localization and phosphorylation. Therefore, we investigated the in vivo phosphorylation of Rex protein in more detail. Phosphorylation of Rex occurred in all HTLV-I-infected cell lines examined in vivo, primarily at serine residues and to a very small extent at threonine residues. Treatment of cells with 12-O-tetradecanoylphorbol-13-acetate (TPA) led to significant but transient enhancement of the incorporation of [32P]orthophosphate into Rex protein. N-terminal truncation of Rex protein abolished TPA-dependent phosphorylation. Chymotryptic digestion of phosphorylated Rex yielded two phosphopeptides. In vivo phosphorylation sites were identified as serine residues 70 and 177 and threonine residue 174. Serine 70 was a TPA-dependent phosphorylation site within a regulatory domain. We have already shown that the protein kinase C inhibitor H-7 (1-(5-isoquinolinylsulfonyl)-2-methylpiperazine) specifically blocked accumulation of viral unspliced gag-pol mRNA. Therefore, the phosphorylation at serine 70 may be involved in the regulation of Rex function in response to extracellular stimuli.
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PMID:Phosphorylation of the Rex protein of human T-cell leukemia virus type I. 140 May 9

Phosphorylation of protein kinase C (PKC) may be an important mode of regulation of this enzyme that plays a key role in mouse skin tumor promotion and in mammalian cell signal transduction. To investigate this possibility, PKC was specifically immunoprecipitated from Abelson murine leukemia virus-transformed normal rat kidney cells that had been metabolically labeled with [32P]orthophosphoric acid. The Mr 80,000 phosphoprotein that was specifically immunoprecipitated from Abelson murine leukemia virus-transformed normal rat kidney cells was found to be identical with purified rat brain PKC that had undergone cell-free autophosphorylation. This is based on comparisons of peptides generated by partial proteolysis with Staphylococcus aureus V8 protease by one-dimensional polyacrylamide-sodium dodecyl sulfate gel electrophoresis and of tryptic peptides by reversed-phase high-pressure liquid chromatography. These data are consistent with phosphorylation of PKC in cells having occurred via autophosphorylation. The autophosphorylation of PKC was stimulated by treatment of C3H 10T1/2 cells with the tumor promoter 12-O-tetradecanoylphorbol-13-acetate or sn-1,2-dioctanoylglycerol. Exposure of cells to 100 nM 12-O-tetradecanoylphorbol-13-acetate for 15 min increased the phosphorylation of PKC by 5-fold in the particulate fraction, while treatment with 100 microM dioctanoylglycerol enhanced phosphorylation of PKC only by 2-fold. Phosphorylation of PKC in response to activation may have significance for altering the sensitivity of PKC to proteolytic down-regulation and/or to subsequent activation.
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PMID:Tumor promoter 12-O-tetradecanoylphorbol-13-acetate and sn-1,2-dioctanoylglycerol increase the phosphorylation of protein kinase C in cells. 187 7

Aggregating agents including phorbol esters which activate protein kinase C induce the rapid phosphorylation of a Mr = 47,000 cytosolic protein in blood platelets (P47 or pleckstrin). This protein is well resolved by analytical 16-BAC----SDS two-dimensional PAGE and was purified from platelets by preparative 16-BAC----SDS PAGE. Polyclonal antibodies were raised to the protein in mice and rabbits. These antisera detected a single protein with the migration of P47 on Western blots of platelet extracts, and the rabbit antisera immunoprecipitated 32P-labelled P47 from platelet cytosol. The presence of P47 in other haematopoietic cells was determined by prelabelling them with 32P and observing increased 32P incorporation into the location of P47 on autoradiographs of 16-BAC----SDS analytical PAGE of cells exposed to phorbol ester. The identity of the phosphoprotein found in this location was further established by probing Western blots of SDS PAGE gels of cultured cell lines with the P47 antisera. P47 was detected in peripheral blood lymphocytes, monocytes and granulocytes (including the granulocytes of two unrelated patients with X-linked chronic granulomatous disease). P47 was also found in HL-60 promyelocytes (especially after differentiation with retinoic acid), U937 histiocytes, HEL leukaemia cells, and Raji 'B' lymphoblasts. It was not detected in normal erythrocytes, K562 leukaemic cells, MOLT-3 'T' lymphoblasts, or in wide range of non-haematopoietic cell lines. We conclude that P47 is a major target for the action of phorbol ester induced phosphorylation in platelets, normal leucocytes and some haematopoietic cell lines. These cells have as their common feature the ability when stimulated to develop adhesive functions on their plasma membranes.
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PMID:P47 phosphoprotein of blood platelets (pleckstrin) is a major target for phorbol ester-induced protein phosphorylation in intact platelets, granulocytes, lymphocytes, monocytes and cultured leukaemic cells: absence of P47 in non-haematopoietic cells. 231 54

Rex, the post-transcriptional regulator of human T-cell leukemia virus type I (HTLV-I), is known to induce accumulation of the unspliced viral gag-pol mRNA. Rex is a phosphoprotein found in the cell nucleolus, whose function may be regulated by its localization and phosphorylation. We have examined the role of phosphorylation on Rex function by using a protein kinase inhibitor, H-7 [1-(5-isoquinolinyl-sulfonyl)-2-methylpiperazine]. Treatment of an HTLV-I infected human T-cell line with H-7 blocked specifically accumulation of the unspliced gag-pol mRNA, resulting in the decreased Gag protein synthesis that corresponds with the decreased in vivo phosphorylation of Rex. In contrast, other viral and cellular products have not been influenced by the level of H-7 used. Therefore, the phosphorylation of Rex is required for the viral RNA partition of HTLV-I.
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PMID:Protein kinase inhibitor H-7 blocks accumulation of unspliced mRNA of human T-cell leukemia virus type I (HTLV-I). 235 16

The Hodgkin-associated Ki-1 antigen occurs in two different molecular forms. The 120-kDa membrane-associated form is a phosphorylated glycoprotein, which is derived from a non-phosphorylated intracellular 84-kDa apoprotein that is co-translationally N-glycosylated with a carbohydrate portion of 6 kDa. The other form of the Ki-1 antigen is a non-glycosylated phosphoprotein of 57 kDa which only occurs intracellularly. Both forms of the antigen are phosphorylated at serine residues. Enzymatic cleavage with sialidase reduced the 120-kDa membrane antigen by about 15 kDa, while its 90-kDa precursor and the 57-kDa intracellular form of the Ki-1 antigen remained unaltered. Pulse-chase experiments revealed that the 57-kDa and 90/120-kDa molecules are synthesized independently of each other. Four to eight hours after synthesis, the degradation of the 120-kDa molecule to a 105-kDa membrane-associated intermediate begins. This is further processed and appears in the cell supernate as a 90-kDa molecule. Hodgkin's disease-derived, Epstein-Barr virus-transformed cell lines and the acute T cell leukemia line MOLT-4 contain both forms of the Ki-1 antigen, whereas only the 57-kDa intracellular antigen is expressed in U266/B1 myeloma cells, in the Burkitt lymphoma cell lines Raji and Daudi and in acute promyelocytic HL-60 leukemia cells.
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PMID:The Hodgkin-associated Ki-1 antigen exists in an intracellular and a membrane-bound form. 254 29


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