Characterization of a protein kinase-phosphoprotein system in free cytoplasmic ribonucleoprotein particles of plasma cell tumours

Egly, Jean‐Marc; Schmitt, Michèle; Kempf, J.

doi:10.1016/0005-2787(76)90280-x

Cited by 15 publications

(4 citation statements)

References 19 publications

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“…The pmRNP-associated kinase examined in this work also has properties similar to those described for the HeLa cell nuclear and plasma cell tumor cytoplasmic mRNP-associated kinases (Egly et al, 1976;Blanchard et a!., 1977). All three kinase activities are Mg2+ dependent and cAMP independent.…”

Section: Discussionsupporting

confidence: 59%

“…Previous work with a combination of sucrose and CsCl gradient approaches has essentially ruled out any contamination of such polysomes with nuclear or cytoplasmic mRNP (Cardelli & Pitot, 1977). This point is important because, as will be discussed below, both nuclear and cytoplasmic mRNP from other systems have been found to contain kinase activity (Egly et al, 1976; Blanchard et al, 1977;Bag & Sells, (979). Our data also suggest that the kinase activity is associated with the pmRNP and not just copurifying with the particles.…”

Section: Discussionmentioning

confidence: 99%

“…Investigators have recently reported that nuclear and cytoplasmic mRNP isolated from a number of different systems contain cAMP-independent protein kinase activity (Egly et al, 1976;Blanchard et al, 1977;Bag & Sells, 1979). We report here that purified rat liver polysomal mRNP also contain associated protein kinase activity with properties similar to those reported for the nuclear and cytoplasmic mRNP-associated kinase(s).…”

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confidence: 99%

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Characterization of protein kinase activity associated with rat liver polysomal messenger ribonucleoprotein particles

Cardelli¹,

Pitot²

1980

Biochemistry

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Poly(adenylic acid)-containing rat liver polysomal messenger ribonucleoprotein particles (pmRNP) were isolated and found to contain protein kinase activity. The association of the enzyme(s) with the particles was confirmed by experiments showing that the protein kinase activity comigrated with the pmRNP on metrizamide gradients and bound to oligo-(dT)-cellulose columns only under conditions where the pmRNP bound. The following properties were determined for the pmRNP-associated kinase(s). Casein and phosvitin were preferred substrates over histone and protamine. The optimal MgCl2 and KCl concentrations were found to be 12.5 and 50 mM, respectively. MnCl2 and CaCl2 could not replace MgCl2 and were inhibitory at low concentrations. The optimum pH range was 7.7--9.0, and the enzyme activity was cAMP independent. A molecular weight of 55 000--60 000 was determined for the kinase(s) by sucrose gradient analysis. The enzyme(s) was capable of phosphorylating proteins endogenous to the pmRNP. Membrane-bound pmRNP contained much less kinase activity than free pmRNP while pmRNP from hepatoma 7777 contained an elevated level of the enzyme(s). The relationship between the protein kinase activity and one of the pmRNP proteins of molecular weight 66 000 is discussed.

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Section: Discussionsupporting

confidence: 59%

Section: Discussionmentioning

confidence: 99%

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confidence: 99%

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Characterization of protein kinase activity associated with rat liver polysomal messenger ribonucleoprotein particles

Cardelli¹,

Pitot²

1980

Biochemistry

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“…50 000 cpm/nmol), 60 pg casein and 30 ~1 column fractions. Samples were incubated for 30 min at 35°C and adsorbed onto Whatman 3 MM filters which were immerged into cold 1% trichloracetic acid then treated as in [8]. 50 100…”

Section: Protein Kinase Assaymentioning

confidence: 99%