Opposing effects of tumour promoters on erythroid differentiation

Miao, R M; Filedsteel, A H; Fodge, Douglas W.

doi:10.1038/274271a0

Cited by 98 publications

(35 citation statements)

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“…Up to now, ATP-dependent HPr phosphorylation was thought to exist only in Gram-positive bacteria with low GC content. The presence of a HPr kinase-like protein in the Gram-negative bacteria Treponema pallidum, a spirochete with a GC content of 52.4-53.7% (21), and in neisseriae, which belong to the ␤ subdivision of eubacteria, suggests that HPr of these bacteria also might be phosphorylated at Ser-46.…”

Section: Resultsmentioning

confidence: 99%

New protein kinase and protein phosphatase families mediate signal transduction in bacterial catabolite repression

Galinier

Kravanja

Engelmann

et al. 1998

Proc. Natl. Acad. Sci. U.S.A.

178

206

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Carbon catabolite repression (CCR) is the prototype of a signal transduction mechanism. In enteric bacteria, cAMP was considered to be the second messenger in CCR by playing a role reminiscent of its actions in eukaryotic cells. However, recent results suggest that CCR in Escherichia coli is mediated mainly by an inducer exclusion mechanism. In many Gram-positive bacteria, CCR is triggered by fructose-1,6-bisphosphate, which activates HPr kinase, presumed to be one of the most ancient serine protein kinases. We here report cloning of the Bacillus subtilis hprK and hprP genes and characterization of the encoded HPr kinase and P-Ser-HPr phosphatase. P-Ser-HPr phosphatase forms a new family of phosphatases together with bacterial phosphoglycolate phosphatase, yeast glycerol-3-phosphatase, and 2-deoxyglucose-6-phosphate phosphatase whereas HPr kinase represents a new family of protein kinases on its own. It does not contain the domain structure typical for eukaryotic protein kinases. Although up to now the HPr modifying͞demodifying enzymes were thought to exist only in Gram-positive bacteria, a sequence comparison revealed that they also are present in several Gram-negative pathogenic bacteria.Carbon catabolite repression (CCR) is the paradigm of signal transduction. It allows bacteria to alter catabolic gene expression in response to the availability of rapidly metabolizable carbon sources. Discovered in the early 1940s in Bacillus subtilis and termed the ''diauxic phenomenon'' (1), one type of molecular mechanism was deciphered in the 1960s in Escherichia coli; in enteric bacteria, changes in the level of cAMP were thought to provide the signal for CCR (2). However, recent results on lacZ expression in E. coli suggest that an increase in the cAMP level reduces only the lag phase of diauxic growth but that the major CCR mechanism is based on inducer exclusion mediated by EIIA Glc of the phosphoenolpyruvate:sugar phosphotransferase system (PTS) (3). It was only in the last decade that the molecular mechanisms underlying CCR in bacilli and other Gram-positive bacteria were partly elucidated (refs. 4-7; for a review, see ref. 8). In these organisms, the complex regulatory cascade is triggered by the ATP-dependent, fructose-1,6-bisphosphate (FBP)-stimulated phosphorylation of Ser-46 in histidine-containing protein (HPr) (9-11), a phosphocarrier protein implicated in carbohydrate transport effected via PTS (12). Signal transduction in CCR continues with a phosphorylation-controlled proteinprotein interaction between HPr and the transcriptional repressor͞activator catabolite control protein A (CcpA) (13,14). ATP-dependent phosphorylation at Ser-46 is a prerequisite for the interaction of HPr with CcpA whereas phosphoenolpyruvate-dependent phosphorylation of HPr at His-15 prevents the complex formation, thus linking PTS-mediated sugar transport to CCR (13). The protein complex formed between CcpA and P-Ser-HPr interacts specifically with an operator site called catabolite responsive element (cre) (15,16). A recent...

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Section: Resultsmentioning

confidence: 99%

New protein kinase and protein phosphatase families mediate signal transduction in bacterial catabolite repression

Galinier

Kravanja

Engelmann

et al. 1998

Proc. Natl. Acad. Sci. U.S.A.

178

206

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“…It apparently induces a cascade of pleiotypic responses which may underlie the process of tumor promotion (4,5). TPA also has a variety of effects on cells in culture and, specifically in hematopoietic cells, can induce or inhibit cellular differentiation (9,17,19,20). In addition, tumor promotion triggered by TPA in some cells is preceded by hyperplasia (15), which may be akin to the mitogenic response of lymphocytes induced by phytohemagglutinin (PHA) or other mitogens.…”

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confidence: 99%

Transcriptional regulation of a tumor promoter and mitogen-inducible gene in human lymphocytes.

Arya¹,

Wong‐Staal²,

Gallo³

1984

Mol. Cell. Biol.

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Tumor-promoting phorbol esters affect a variety of cellular functions which may underlie tumor promotion. We isolated from human lymphocytes a cDNA clone whose gene is inducible by the phorbol ester 12-O-tetradecanoyl-phorbol-13-acetate as well as by the T-cell mitogen phytohemagglutinin. Nuclear transcription experiments suggested that this induction is primarily caused by the increased transcription of the gene. It is interesting that this gene is expressed constitutively in human T-cell leukemia virus-infected mature T cells. The results support the notion that 12-O-tetradecanoyl-phorbol-13-acetate can affect cellular functions by causing transcriptional activation of specific genes.

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“…Trichostatin C also induced another kind of mouse erythroleukemic cells (RVI33) transformed by Rausher virus 7) into benzidine positive cells at a concentration almost the same as that for Friend cells.…”

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confidence: 99%