Parallel regulation of cyclic amp‐dependent protein kinase and phosphoprotein phosphatase in rat thyroid

Huprikar, Shankar; Lang, Michael; Friedman, Yochanan; Burke, Gerald

doi:10.1016/0014-5793(79)80271-9

Cited by 12 publications

(2 citation statements)

References 21 publications

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“…32Pi radioactivity was counted following extraction with ammonium molybdate and isobutanol [30]. Activity is expressed as pmol 32Pi released/lO min.…”

Section: Phosphoprotein Phosphatase Assaysmentioning

confidence: 99%

“…The [32P]histone phosphatase assay [29] was carried out in a total volume of 200 pl containing a 50-pl aliquot of a DEAE-cellulose column fraction, [ 32P]histone f2b (30 pg), 50 mM Tris (pH 7.9, 1 mM dithiothreitol and 2.5 mM MgClz at 30°C. 32Pi radioactivity was counted following extraction with ammonium molybdate and isobutanol [30]. Activity is expressed as pmol 32Pi released/lO min.…”

Section: Phosphoprotein Phosphatase Assaysmentioning

confidence: 99%

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Insulin-induced increases in the activity of the spontaneously active and ATP . Mg-dependent forms of phosphatase-1 in alloxan-diabetic rat liver

Dragland-Meserve¹,

Webster²,

Botelho³

1985

Eur J Biochem

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Liver supernatant from normal and alloxan-diabetic rats was fractionated by DEAE-cellulose chromatography and the separated phosphoprotein phosphatase fractions were assayed with [32P]histone fzb, [32P]phosphorylase a and [32P]phosphorylase kinase as substrates. In diabetic rat liver, one of the phosphatase fractions found in the normal liver was significantly reduced. This fraction was identified as a mixture of the spontaneously active form and the ATP . Mg-dependent form of phosphoprotein phosphatase-I (F,) based on sensitivity to inhibitor-2, substrate specificity, and the fact that it could be activated 42 -70% by glycogen synthase kinase-3 in the presence of ATP . Mg. Further analysis of this fraction showed that liver cytosol from diabetic rats contained 62-79% lower spontaneously active phosphatase-I activity and 40 -51 % lower combined spontaneously active and ATP . Mg-dependent protein phosphatase-1 (F,) activity. Insulin administration increased the spontaneously active and the ATP . Mg-dependent protein phosphatase-I activities approximately 45% and 36%, respectively, in alloxan-diabetic rats. These data imply that the lower levels of spontaneously active phosphatase-1 activity in diabetic rat liver cannot be explained by presuming phosphatase-1 to have been present as Fc, the inactive form. Moreover, insulin restored the total activity of the spontaneously active and activatable forms of phosphatase-I to those present in normal liver implying that both forms of phosphatase-I activity are under hormonal control.

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“…32Pi radioactivity was counted following extraction with ammonium molybdate and isobutanol [30]. Activity is expressed as pmol 32Pi released/lO min.…”

Section: Phosphoprotein Phosphatase Assaysmentioning

confidence: 99%

Section: Phosphoprotein Phosphatase Assaysmentioning

confidence: 99%

Insulin-induced increases in the activity of the spontaneously active and ATP . Mg-dependent forms of phosphatase-1 in alloxan-diabetic rat liver

Dragland-Meserve¹,

Webster²,

Botelho³

1985

Eur J Biochem

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Differential effects of polyamines on rat thyroid protein kinase activities

Levasseur

Henricks

Poleck

et al. 1985

J of Cellular Biochemistry

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Ornithine decarboxylase, the rate-limiting enzyme in polyamine biosynthesis, has been shown to be regulated in thyroid by thyrotropin both in vivo and in vitro. Little, however, is known of the role of polyamines in thyroid cell function. Since studies in other tissues suggest that polyamines may influence protein phosphorylation, we studied the effect of the polyamines on various protein kinase activities in rat thyroid. Putrescine, spermidine, and spermine inhibit cyclic-AMP-dependent histone H1 kinase activity when measured in the cytosol fraction of rat thyroid; this effect is largely reproduced by NaCl concentrations of equivalent ionic strength. Both spermidine and spermine effect a 1.6-2.4-fold increase in cytosolic cyclic-AMP-independent (messenger-independent) casein kinase activity; stimulation by both polyamines is maximal at 5mM. A similar profile of stimulation is observed for messenger-independent casein kinase activity in crude nuclear preparations. Sodium chloride fails to stimulate both cytosolic and nuclear messenger-independent casein kinase activities at ionic strength equivalent to the spermine concentrations used. Spermine, but not putrescine, spermidine, or sodium chloride, inhibits calcium/phospholipid-dependent protein kinase C activity in cytosol extracts partially purified by DEAE chromatography. These findings suggest that regulation of protein kinase(s) by polyamines may represent a proximal locus (i) of action of thyrotropin-regulated ornithine decarboxylase activity in thyroid.

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The Role of Cyclic Nucleotides in the Thyroid Gland

Holmes¹,

Field²

1982

Handbook of Experimental Pharmacology

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Parallel regulation of cyclic amp‐dependent protein kinase and phosphoprotein phosphatase in rat thyroid

Cited by 12 publications

References 21 publications

Insulin-induced increases in the activity of the spontaneously active and ATP . Mg-dependent forms of phosphatase-1 in alloxan-diabetic rat liver

Insulin-induced increases in the activity of the spontaneously active and ATP . Mg-dependent forms of phosphatase-1 in alloxan-diabetic rat liver

Differential effects of polyamines on rat thyroid protein kinase activities

The Role of Cyclic Nucleotides in the Thyroid Gland

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