Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.1.3 (ATPase)
 65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In a previous report on the ontogeny of the ovarian adenosine 3',5'-monophosphate (cAMP)-dependent protein kinase activity during prepubertal development of the rat, we concluded that the 4-fold decline in cAMP-dependent protein kinase activity observed in ovaries of 21- to 23-day-old rats was due to the presence of a heat-labile inhibitor in the ovarian extracts (Hunzicker-Dunn et al., 1984). We developed an assay for this ovarian kinase inhibitor activity that was based on the observation that ovarian cytosol added to an exogenous catalytic subunit of cAMP-dependent protein kinase caused a time-dependent and ovarian cytosol protein concentration-dependent inhibition of exogenous catalytic subunit phosphotransferase activity. The present studies were conducted to evaluate the basis for this catalytic subunit inhibitor present in soluble rat ovarian extracts of prepubertal-aged rats. This inhibitor activity was absent from cytosol extracts of rat corpora lutea, rat liver, rabbit follicles, and rabbit corpora lutea. Inhibitor activity present in rat ovarian cytosol was not attributable to insufficient levels of the phosphorylation substrate Kemptide. Inhibitor activity was also not related to the presence of the large amount of catalytic subunit-free regulatory subunit of the cAMP-dependent protein kinase present in ovarian extracts of late juvenile-aged rats. Inhibitor activity, however, did correlate with an endogenous adenosine triphosphatase (ATPase) activity that reduced assay ATP concentrations below levels needed to accurately measure phosphotransferase activity, despite the presence of sodium fluoride (an ATPase inhibitor) and ATP concentrations 5- to 15-fold greater than the Km of the kinase for ATP.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Modulation of soluble ovarian adenosine 3',5'-monophosphate-dependent protein kinase activity during prepubertal development in the rat. II. Evaluation of the catalytic subunit inhibitor activity. 252 67

Tyrosine protein kinases (TPKs) have been implicated in mitotic signalling in a wide range of cells including lymphocytes. We describe here the partial characterization of a heat stable TPK inhibitor from both normal and malignant human lymphoid cells. Inhibitory activity was not attributable to contaminating ATPase, protease or phosphatase activities or to the Ca2+-binding protein S100. Preparations of the TPK inhibitor did not reduce the activity of cAMP-dependent protein kinase. While the inhibitor decreased the activity of TPKs towards an exogenous peptide substrate, it did not affect the autophosphorylation of microsomal TPKs. These results raise the possibility that the activity of TPKs in lymphoid cells may be regulated by an inhibitor protein.
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PMID:An endogenous inhibitor of the protein tyrosine kinase activity of normal and malignant human lymphoid cells. 252 67

1. Myofibrils isolated from Mercenaria mercenaria were phosphorylated by endogenous kinase. Over a range of ionic strengths only paramyosin was phosphorylated. 2. Thiophosphorylation of paramyosin caused an inhibition of steady-state actin-activated ATPase activity of the myofibrils. 3. It is proposed that the endogenous kinase is the catalytic subunit of the cAMP-dependent protein kinase. 4. The sequence around the phosphorylation site was determined. 5. The phosphorylation site probably is close to the C-terminus of the paramyosin molecule.
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PMID:Phosphorylation of paramyosin. 253 91

Highly purified sarcoplasmic reticulum (SR) has been prepared from dog hearts and has been incubated with the triplet probe erythrosinyl isothiocyanate to specifically label the Ca2+-stimulated ATPase (Ca2+-ATPase) of the SR. The rotational mobility of the Ca2+-ATPase has been studied in this erythrosin-labelled SR using time-resolved phosphorescence polarization. Qualitatively, the mobility of the cardiac Ca2+-ATPase resembles that of skeletal muscle SR Ca2+-ATPase. Addition of Ca2+ to SR affects the mobility of the Ca2+-ATPase in a way consistent with a segment of the ATPase altering its orientation relative to the plane of the membrane. Phosphorylation of phospholamban in cardiac SR by the purified catalytic subunit of cAMP-dependent protein kinase, which is known to increase the activity of the Ca2+-ATPase by deinhibition, also alters measured anisotropy. The changes observed are not compatible with dissociation of the Ca2+-ATPase from phospholamban after the latter is phosphorylated. The data are more consistent with phospholamban associating with the Ca2+-ATPase following phosphorylation, or more complex models in which only the hydrophilic domain of phospholamban binds with and dissociates from the Ca2+-ATPase.
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PMID:The effects of calcium, temperature and phospholamban phosphorylation on the dynamics of the calcium-stimulated ATPase of canine cardiac sarcoplasmic reticulum. 254 Aug 39

The primary structure of a region of the erythrocyte plasma membrane calcium pump which is phosphorylated by the cAMP-dependent protein kinase has been determined. The sequence is A-P-T-K-R-N-S-S(P)-P-P-P-S-P-D. The site is located between the calmodulin binding domain and the C-terminus of the ATPase. The ATPase is phosphorylated only at this site by the cAMP-dependent protein kinase, and the phosphorylation is inhibited by calmodulin. The effect of the phosphorylation is to decrease the Km for Ca2+ of the purified ATPase from about 10 microM to about 1.4 microM and to increase the Vmax of ATP hydrolysis about 2-fold.
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PMID:Primary structure of the cAMP-dependent phosphorylation site of the plasma membrane calcium pump. 254 72

The plasma-membrane ATPase of Saccharomyces cerevisiae is a proton pump whose activity, essential fro proliferation, is subject to regulation by nutritional signals. The previous finding that the CDC25 gene product is required for the glucose-induced H+-ATPase activation suggested that H+-ATPase activity is regulated by cAMP. Analysis of starvation-induced inactivation and glucose-induced activation of the H+-ATPase in mutants affected in activity of the RAS proteins, adenylyl cyclase or cAMP-dependent protein kinase showed that nutritional regulation of H+-ATPase activity does not depend directly on any of these factors. We conclude that adenlyl cyclase does not mediate all nutritional responses. This also indicates that the specific CDC25 requirement for the glucose-induced activation of the H+-ATPase identifies a new function for the CDC25 gene product, a function that appears to be independent of CDC25-mediated modulation of the RAS/adenylyl cyclase/cAMP pathway.
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PMID:cAMP- and RAS-independent nutritional regulation of plasma-membrane H+-ATPase activity in Saccharomyces cerevisiae. 255 50

The calmodulin content in cardiomyocyte cytosol of hypoxic myocardium is increased compared to normal level. This is unaccompanied by differences in the stimulating effect of calmodulin on Ca2+ transport in sarcoplasmic reticulum (SR) of ischemic heart. The decrease of the endogenous cAMP-dependent protein kinase activity in ischemia is associated with the lowered resistance to trypsinolysis of Ca2+ transport in SR (trypsin/microsomal protein ratio is 1:10) with simultaneous Ca-ATPase activation. In the presence of exogenous protein kinase and cAMP the protective effect of phosphorylation on Ca2+ transport in SR vesicles of hypoxic cardiomyocytes treated with trypsin for 10 min reaches the same level as in intact heart.
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PMID:[cAMP, calmodulin-dependent stimulation and stability to proteolysis of Ca 2+ transport in the heart sarcoplasmic reticulum]. 256 Dec 65

The cellular localization of DARPP-32, a dopamine- and cAMP-regulated phosphoprotein of Mr 32,000 that appears to mediate certain actions of dopamine in the mammalian brain by acting as an inhibitor of protein phosphatase 1, was studied in the kidney of several species. DARPP-32 mRNA and DARPP-32-like immunoreactivity were found in the cytoplasm of cells in the thick ascending limb of the loop of Henle. The specific dopamine DA1 agonist SKF 82526 caused a dose-dependent inhibition of Na+,K+-ATPase activity, which could be blocked by SCH 23390, a specific DA1 antagonist, and by PKI-(5-24) amide, a specific inhibitor of cAMP-dependent protein kinase. The results indicate that DA1 dopamine receptors and DARPP-32, an intracellular third messenger for dopamine, are part of the signal-transduction process for dopamine acting on renal tubule cells.
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PMID:Dopamine- and cAMP-regulated phosphoprotein (DARPP-32) and dopamine DA1 agonist-sensitive Na+,K+-ATPase in renal tubule cells. 257 60

The mechanisms of cell proliferative activity regulation under the effect of growth factors, mitogens, virus transformation, etc. were analyzed. Changes in the location of cAMP-dependent protein kinase caused by these factors, the effect of the nerve growth factor on the activities of protein kinase and high-affinity ATPase, and the mechanism of antiproliferative action of staphylococcal enterotoxin A were specified. Data on receptor-independent intracellular penetration of protein factors hydrophobized by fatty acid residues are overviewed.
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PMID:[The main pathogenetic mechanisms of disorders of the detoxication function of the liver in endogenous toxemia of various etiologies]. 262 79

We investigated the action of vanadate on protein phosphorylation in microvessels isolated from rat brain. We found that a stimulation of protein phosphorylation from 32P-ATP occurs, in the presence of different concentrations of vanadate, 10(-3) M being the most effective dose. This action was time-dependent, and it was more evident after 60 s of treatment. The contribution of ATPase inhibition caused by vanadate appears to be negligible. In addition a stimulation of cAMP-dependent protein kinase activity was observed. The pattern of protein phosphorylation showed that exposure to 10(-3) M vanadate resulted in a nonspecific stimulation of protein phosphorylation concomitantly with a selective inhibition of the 55 KDa protein phosphorylation. The nature of this protein is also discussed.
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PMID:Evidence for a regulatory action of vanadate on protein phosphorylation in brain microvessels. 278 20


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