Protein Kinases in Rat Testes: Evidence for Different Fractions of the Enzyme

1975 ◽  
Vol 53 (2) ◽  
pp. 207-214 ◽  
Author(s):  
Elena A. Bernard ◽  
G. F. Wassermann
Keyword(s):  
Protein Kinase ◽  
Protein Kinases ◽  
Kinase Activity ◽  
Deae Cellulose ◽  
Affinity Column ◽  
Substrate Affinity ◽  
Protein Kinase Activity ◽  
Rat Testis ◽  
Peak Number ◽  
Histone Lysine

Protein kinase activity of rat testis homogenate was separated into five fractions by means of pH 4.8 acidification and DEAE-cellulose chromatography. The five fractions showed a peculiar pattern of activity and cAMP dependency with the substrates used: casein, protamine, histone mixture, arginine-rich histone, lysine-rich histone, and phosvitin. The casein–sepharose substrate affinity column separated two fractions from the pH 4.8 precipitate. Peak number one phosphorylates histone preferently and is cAMP-dependent, while peak number two has a strong affinity toward casein as substrate and is not cAMP-dependent.

scholarly journals Phosphorylation of microtubule-associated proteins by a Ca2+/calmodulin-dependent protein kinase.

1984 ◽  
Vol 99 (1) ◽  
pp. 11-19 ◽  
Author(s):  
H Schulman
Keyword(s):  
Protein Kinase ◽  
Kinase Activity ◽  
Deae Cellulose ◽  
Affinity Column ◽  
Protein Kinase Activity ◽  
Dependent Protein Kinase ◽  
Apparent Homogeneity ◽  
Associated Proteins ◽  
Dependent Protein ◽  
Considerable Homology

In an earlier study I demonstrated that rat brain cytosol contains a Ca2+/calmodulin-dependent protein kinase activity that phosphorylates microtubule-associated protein 2 (MAP-2) but not MAP-1. Comparison of sites of phosphate incorporated in MAP-2 catalyzed by the Ca2+/calmodulin-dependent kinase activity and the cyclic AMP-dependent protein kinase activity in cytosolic extracts revealed distinct sites of phosphorylation (Schulman, H., 1984, Mol. Cell. Biol., 4:1175-1178; abstract by me and J.A. Kuret and K.H. Spitzer [1983, Fed. Proc., 42:2250]. I have now used MAP-2 as a substrate to purify the Ca2+/calmodulin-dependent protein kinase responsible for MAP-2 phosphorylation. The brain appears to contain a single predominant Ca2+/calmodulin-dependent protein kinase that phosphorylates MAP-2. The enzyme was purified to apparent homogeneity by column chromatography using DEAE-cellulose, phosphocellulose, hydroxylapatite, Sepharose 6B, and a calmodulin-Sepharose affinity column. The 580,000-dalton holoenzyme consists of 51,000- and 60,000-dalton subunits. The purified enzyme phosphorylates MAP-2 at the same "sites" that are phosphorylated in cytosolic extracts and thus has the same specificity as the activity present in cytosol. Analysis of phosphorylated MAP-2.1 and MAP-2.2, the two components of MAP-2, suggests considerable homology in their phosphorylated domains.

scholarly journals S183. ABNORMALITIES IN SERINE/THREONINE SIGNALING NETWORKS IN SEVERE NEUROPSYCHIATRIC ILLNESS: DEVELOPMENT OF A PIPELINE TO EXPLORE ABNORMALITIES OF KINASE ACTIVITY AND IDENTIFY NOVEL TREATMENT STRATEGIES FOR SCHIZOPHRENIA

2020 ◽  
Vol 46 (Supplement_1) ◽  
pp. S107-S108
Author(s):  
Robert McCullumsmith ◽  
Khaled Alganem ◽  
Nicholas Henkel ◽  
Abdul Hammoud ◽  
Rammohan Shukla ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Kinases ◽  
Kinase Activity ◽  
Biological Pathways ◽  
Signaling Networks ◽  
Protein Kinase Activity ◽  
Drug Candidates ◽  
Group 10 ◽  
Disease Signatures ◽  
Neuropsychiatric Illness

Abstract Background Abnormalities of cellular signaling are well characterized in neuropsychiatric illnesses, including schizophrenia. Changes in signaling pathways reflect the underlying genetic, environmental, and epigenetic perturbations driving disease phenotypes. A shortcoming of most signaling studies is a focus on one or a few protein kinases at a time, a limitation since protein kinases work in networks with other kinases, phosphatases, and regulatory molecules to effect signaling events. We addressed this challenge by employing a kinome array platform that simultaneously measures protein kinase activity at hundreds of reporter peptide substrates. We then developed a novel bioinformatics pipeline to identify protein kinase nodes, signaling networks, upstream biological pathways, and drug candidates that “reverse” kinomic disease signatures. Methods Postmortem DLPFC brain samples from subjects with schizophrenia (n = 20 per group, 10 males and 10 females per group), were compared to age, PMI and pH matched control subjects (n = 20 per group, 10 males and 10 females per group) using the Pamgene12 serine/threonine kinome array chip. Samples were pooled by diagnosis and gender, and run in triplicate. The R-shiny app KRSA was created to automate assignment of kinases, perform permutation analyses, identify biological pathways, and connect to iLINCs for identification of drugs that reverse kinomic disease signatures. We also performed targeted confirmation studies using specific kinase activity assays, QPCR, and western blot analyses. Results We identified unique and common kinase nodes for each diagnostic group. Several of the nodes (for example AKT) are well characterized in schizophrenia, while others have not previously been identified (such as AMPK). We used AMPK KD cultures and AMPK KO brain tissues to demonstrate the validity if the kinome array for this protein kinase. We used standard kinase activity assays for AMPK and found decreased activity for AMPK (P < 0.05). We also found decreased expression of transcripts for the regulatory subunits of AMPK (P < 0.05). We identified several unique biological pathways, as well as candidate drugs, associated with the disease signature in schizophrenia. Discussion Our results confirm well characterized signaling defects in severe neuropsychiatric illness, and identify novel signaling nodes for further study. Confirmation studies for AMPK kinase show significant changes in expression and activity of this kinase, suggesting perturbation of energy sensing and production pathways in schizophrenia. Bioenergetic pathways may be targeted by myriad mechanisms, and we identified several drug candidates that might help restore this pathway in afflicted persons. Overall our novel workflow and pipeline provides a promising new avenue for understanding the complex signaling perturbations found in brain diseases and may provide new leads for developing treatments for schizophrenia and other cognitive disorders.

Biochemical changes accompanying enhanced cardiac contractility by ionophore A23187

1985 ◽  
Vol 249 (6) ◽  
pp. H1204-H1210 ◽  
Author(s):  
J. J. Murray ◽  
P. W. Reed ◽  
J. G. Dobson
Keyword(s):  
Protein Kinase ◽  
Protein Kinases ◽  
Kinase Activity ◽  
Protein Kinase Activity ◽  
Ionophore A23187 ◽  
Phosphorylase Activity ◽  
Dependent Protein Kinase ◽  
Camp Content ◽  
Camp Dependent Protein Kinase ◽  
Dependent Protein

We have reported that the divalent cation ionophore A23187, like the beta-adrenergic agonist isoproterenol, increased the force of contraction and rate of relaxation and shortened the duration of contraction of papillary muscles isolated from guinea pigs. A23187 produced a fall in resting tension and decreased the contracture tension of K +/- depolarized muscles, as did isoproterenol. In the present studies, isoproterenol produced a concentration-dependent, rapid, and sustained increase in the cyclic AMP (cAMP) content of papillary muscle. In contrast, A23187 had no detectable effect on cAMP levels, even in the presence of the phosphodiesterase inhibitor, papaverine. Neither drug, at concentrations maximal for contractile effects, altered cyclic GMP (cGMP). Isoproterenol increased the cAMP-dependent protein kinase activity ratio, whereas A23187 did not change the activity of this enzyme. However, both A23187 and isoproterenol produced a concentration-dependent increase in phosphorylase activity. Concentrations of A23187 or isoproterenol that enhanced contractility maximally increased the alkali-labile phosphate (by ca. 35%) but were without effect on the acid-labile, alkali-stable phosphate in the total acid precipitable protein. Contractile effects of isoproterenol, which reflect activated Ca2+ uptake, and the increase in phosphorylase activity produced by this agent are believed to be due to an increase in cAMP with subsequent activation of cAMP-dependent protein kinases and phosphorylation of proteins. A23187 may produce similar contractile effects without an increase in cAMP or cAMP-dependent protein kinase activity by activating other protein kinases and/or inhibiting phosphoprotein phosphatases, most likely by its effects on intracellular calcium.

Introduction to the Kinases in Diabetes Biochemical Society focused meeting: are protein kinases good targets for antidiabetic drugs?

2005 ◽  
Vol 33 (2) ◽  
pp. 339-342 ◽  
Author(s):  
M.P. Coghlan ◽  
D.M. Smith
Keyword(s):  
Insulin Resistance ◽  
Protein Kinase ◽  
Protein Kinases ◽  
Kinase Activity ◽  
Whole Body ◽  
Protein Kinase Activity ◽  
Pharmacological Agents ◽  
Insulin Resistant ◽  
Insulin Mimetic ◽  
Glucose Homoeostasis

Insulin regulates whole-body glucose homoeostasis by modulating the activities of protein kinases in its target tissues: muscle, liver and fat. Defects in insulin's ability to modulate protein kinase activity lead to ‘insulin resistance’ or impaired insulin action. Insulin resistance in combination with defective insulin secretion from the pancreas results in the elevated blood glucose levels that are characteristic of diabetes mellitus. Pharmacological agents that selectively modulate protein kinase activities in insulin-resistant tissues may act either as insulin-sensitizing or insulin-mimetic drugs. Consistent with this, small molecule modulators of a number of protein kinases have demonstrated efficacy in animal models of insulin resistance and diabetes. Moreover, emerging data in humans suggest that marketed anti-diabetic agents may also act in part through modulating protein kinase activities. This meeting was convened to consider the potential to treat insulin resistance and Type II diabetes by modulating protein kinase activity.

scholarly journals Toxoplasma gondiiAttachment to Host Cells Is Regulated by a Calmodulin-like Domain Protein Kinase

2001 ◽  
Vol 276 (15) ◽  
pp. 12369-12377 ◽  
Author(s):  
Heidi Kieschnick ◽  
Therese Wakefield ◽  
Carl Anthony Narducci ◽  
Con Beckers
Keyword(s):  
Protein Kinase ◽  
Protein Kinases ◽  
Kinase Activity ◽  
Host Cells ◽  
Protein Kinase Activity ◽  
Calcium Dependent ◽  
Dependent Protein ◽  
Calcium Dependent Protein Kinases ◽  
Domain Protein

The role of calcium-dependent protein kinases in the invasion ofToxoplasma gondiiinto its animal host cells was analyzed. KT5926, an inhibitor of calcium-dependent protein kinases in other systems, is known to block the motility ofToxoplasmatachyzoites and their attachment to host cells.In vivo, KT5926 blocks the phosphorylation of only three parasite proteins, and in parasite extracts only a single KT5926-sensitive protein kinase activity was detected. This activity was calcium-dependent but did not require calmodulin. In a search for calcium-dependent protein kinases inToxoplasma, two members of the class of calmodulin-like domain protein kinases (CDPKs) were detected. TgCDPK2 was only expressed at the mRNA level in tachyzoites, but no protein was detected. TgCDPK1 protein was expressed inToxoplasmatachyzoites and cofractionated precisely with the peak of KT5926-sensitive protein kinase activity. TgCDPK1 kinase activity was calcium-dependent but did not require calmodulin or phospholipids. TgCDPK1 was found to be inhibited effectively by KT5926 at concentrations that block parasite attachment to host cells.In vitro, TgCDPK1 phosphorylated three parasite proteins that migrated identical to the three KT5926-sensitive phosphoproteins detectedin vivo. Based on these observations, a central role is suggested for TgCDPK1 in regulatingToxoplasmamotility and host cell invasion.

scholarly journals A phospholipid-stimulated protein kinase from Dictyostelium discoideum

1989 ◽  
Vol 260 (2) ◽  
pp. 557-561 ◽  
Author(s):  
B Jiménez ◽  
A Pestaña ◽  
M Fernandez-Renart
Keyword(s):  
Protein Kinase ◽  
Protease Inhibitors ◽  
Dictyostelium Discoideum ◽  
Kinase Activity ◽  
Deae Cellulose ◽  
Protein Kinase Activity ◽  
Endogenous Protein ◽  
Exogenous Substrate ◽  
Intermolecular Reactions

A protein kinase with unusual characteristics has been found in Dictyostelium discoideum. This kinase can use histone H1 as exogenous substrate, and the activity is stimulated by phospholipids, but not by Ca2+. This enzyme has been partially purified by using chromatography on DEAE-cellulose DE-52, spermine-agarose and phosphatidylserine-polyacrylamide. The protein kinase activity is very labile, even in the presence of protease inhibitors, making further purification difficult. In the activity-containing fractions, an endogenous protein of 140 kDa is labelled in vitro with [gamma-32P]ATP under conditions in which intramolecular rather than intermolecular reactions are favoured. This protein is labelled only in the presence of phospholipids, but not of Ca2+. We propose that the 140 kDa phosphoprotein might be the autophosphorylated enzyme.

Protein Kinases in Testes of Adult and Prepuberal Rats

1974 ◽  
Vol 52 (7) ◽  
pp. 563-569 ◽  
Author(s):  
E. A. Bernard ◽  
G. F. Wassermann
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Enzymatic Activity ◽  
Protein Kinases ◽  
Kinase Activity ◽  
Seminiferous Tubules ◽  
Interstitial Tissue ◽  
Protein Kinase Activity

Cyclic AMP dependence of protein kinase activity (PrK) in testicular homogenates varies according to the substrate used (histone > casein). The enzymatic activity increased during maturation, notably between 35 and 45 days of age. The increment is higher in isolated seminiferous tubules than in interstitial tissue. Upon centrifugation at pH 4.8, two dissimilar PrK preparations can be obtained. The enzymatic activity of both fractions increased with maturation.

Type I and II cAMP-dependent ecto-protein kinases in goat epididymal spermatozoa and their enriched activities in forward-motile spermatozoa

1990 ◽  
Vol 68 (2) ◽  
pp. 459-470 ◽  
Author(s):  
Chinmoy S. Dey ◽  
Gopal C. Majumder
Keyword(s):  
Plasma Membrane ◽  
Protein Kinase ◽  
Protein Kinases ◽  
Kinase Activity ◽  
Specific Activity ◽  
Diazonium Salt ◽  
Intact Cell ◽  
Deae Cellulose ◽  
Type I ◽  
Sperm Plasma Membrane

Several lines of evidence have demonstrated conclusively the presence of cAMP-dependent protein kinase (ecto-RC) activity on the external surface of goat cauda-epididymal intact spermatozoa. The intact-cell ecto-kinase that caused transfer of the terminal phosphate of exogenous ATP to the serine and threonine residues of exogenous histone was specifically activated by cAMP. As well, the ecto-kinase caused phosphorylation of the synthetic peptide Kemptide. The isolated spermatozoa, before or after incubation with reaction mixture for ecto-kinase assays, were ~ 99.5% viable, as shown by the analyses of ethidium bromide fluorescence and the cytosolic marker enzymes lactic dehydrogenase and 3-phosphoglycerate kinase. The ecto-kinase activity was not due to contamination of epididymal plasma and damaged cells or to protein kinase that may have leaked from the cells. There was little uptake of ATP and histone by the cells. The intact-cell kinase activity was strongly (80–90%) inhibited by treatment with membrane nonpenetrating surface probes: p-chloromercuriphenylsulfonic acid (2 μM), diazonium salt of sulfanilic acid (DSS, 0.5 mM), and proteases such as trypsin, chymotrypsin, and pronase (each 125 μg/mL). Disruption of sperm plasma membrane by sonication or Triton X-100 (0.2%) caused about a fivefold increase of the intact sperm kinase activity. Highly purified sperm plasma membrane (PM) possessed ecto-kinase activity that was resolved into type I and II kinases by DEAE-cellulose chromatography, the type I isoenzyme being the major (~ 70%) enzymic species. Treatment of the intact spermatozoa with DSS prior to isolation of PM caused a marked loss of the activities of both the isoenzymes, indicating thereby the "ecto" nature of the PM-bound type I and II kinases. Preparations of vigorously forward-motile spermatozoa with 100% intactness had approximately fourfold higher specific activity of the ecto-kinase than the "composite" cells from which the former cells were isolated. However, the profiles of the type I and II ecto-kinases of the composite, as well as forward-motile spermatozoa, were nearly identical. The data are consistent with the view that ecto-kinases may have role in the regulation of flagellar motility.Key words: spermatozoa, ecto-protein kinases, cAMP, plasma membrane, cell intactness.

Sign in / Sign up

Export Citation Format

Share Document