scholarly journals Nuclear envelope of the seminal-vesicle epithelium

1981 ◽  
Vol 198 (2) ◽  
pp. 259-264 ◽  
Author(s):  
C M Veneziale ◽  
M E Utz ◽  
R C Steer ◽  
M J Wilson ◽  
K Ahmed
Keyword(s):  
Protein Kinase ◽  
Nuclear Envelope ◽  
Seminal Vesicle ◽  
Envelope Protein ◽  
Sodium Citrate ◽  
Kinase Activity ◽  
Specific Activity ◽  
Protein Kinase Activity ◽  
Deoxyribonuclease I ◽  
Transmission Electron

The nuclear envelope of seminal-vesicle epithelium was isolated by a procedure involving enzymic digestion with deoxyribonuclease I, sonication in the presence of 0.34 M-sodium citrate, and centrifugation through sucrose density gradients. The mass of envelope DNA was only 0.8% of that of envelope protein, and by transmission electron microscopy the envelope was 98-99% pure. We showed that the envelope possess a protein kinase activity which is uninfluenced by cyclic nucleotides. Both lysine-rich histone and dephosphophosvitin as substrates gave a greater specific activity than did envelope protein itself. Optimum requirements with respect to Na+, Mg2+, pH and ATP were established for each substrate, and the influence of other factors on enzyme activity was investigated. Data, obtained mainly with the use of lysine-rich histone, are presented which indicate that nuclear envelope from intact and 96 h-castrated guinea pigs may have equal protein kinase activities and, in separate experiments, equal phosphoprotein phosphatase activities. Clarification of these initial observations must await identification of the natural substrates or the envelope's phosphorylation-dephosphorylation reactions.

scholarly journals The Saccharomyces cerevisiae YAK1 gene encodes a protein kinase that is induced by arrest early in the cell cycle.

1991 ◽  
Vol 11 (8) ◽  
pp. 4045-4052 ◽  
Author(s):  
S Garrett ◽  
M M Menold ◽  
J R Broach
Keyword(s):  
Cell Cycle ◽  
Protein Kinase ◽  
Kinase Activity ◽  
Specific Activity ◽  
S Phase ◽  
Protein Kinase Activity ◽  
Dependent Protein Kinase ◽  
Protein Levels ◽  
Cycle Arrest ◽  
Dependent Protein

Null mutations in the gene YAK1, which encodes a protein with sequence homology to known protein kinases, suppress the cell cycle arrest phenotype of mutants lacking the cyclic AMP-dependent protein kinase (A kinase). That is, loss of the YAK1 protein specifically compensates for loss of the A kinase. Here, we show that the protein encoded by YAK1 has protein kinase activity. Yak1 kinase activity is low during exponential growth but is induced at least 50-fold by arrest of cells prior to the completion of S phase. Induction is not observed by arrest at stages later in the cell cycle. Depending on the arrest regimen, induction can occur either by an increase in Yak1 protein levels or by an increase in Yak1 specific activity. Finally, an increase in Yak1 protein levels causes growth arrest of cells with attenuated A kinase activity. These results suggest that Yak1 acts in a pathway parallel to that of the A kinase to negatively regulate cell proliferation.

scholarly journals Changes in protein kinase activity in rat testes during development

1977 ◽  
Vol 162 (2) ◽  
pp. 465-467 ◽  
Author(s):  
E A Bernard ◽  
G F Wassermann
Keyword(s):  
Protein Kinase ◽  
Kinase Activity ◽  
Specific Activity ◽  
Protein Kinase Activity ◽  
Embryonic Life ◽  
Old Rats

Protein kinase activity in rat testes remained fairly constant from day 16 1/2 of embryonic life up to 10 days after birth. At the 21st postnatal day a nadir of activity was observed, and after an increase at 35 days of age a decrease in activity at 60 days was seen. The enzyme reached maximal specific activity in the testes of 90-day-old rats.

Protein kinases in brown adipose tissue of developing rats: substrate specificities, separation, and changes in activity during development

1978 ◽  
Vol 56 (9) ◽  
pp. 869-874 ◽  
Author(s):  
Josef P. Skala ◽  
Brian L. Knight
Keyword(s):  
Adipose Tissue ◽  
Protein Kinase ◽  
Brown Adipose Tissue ◽  
Kinase Activity ◽  
Specific Activity ◽  
Brown Fat ◽  
Supernatant Fraction ◽  
Protein Kinase Activity ◽  
Nonhistone Proteins ◽  
Brown Adipose

Protein kinase activity in the 100 000 × g supernatant fraction of brown adipose tissue was assayed with various proteins as substrates. Greatest activity was obtained with histone subfraction f2b and the lowest activity with protamine. cAMP stimulated the phosphorylation of histones but not that of the other proteins. The specific activity of protein kinase in brown fat of rats changed during infancy, and the pattern of changes was different with different protein substrates.Electrophoresis of the tissue-soluble extract gave nine major bands of protein kinase activity. These were assayed on the gels under the optimal conditions for each substrate. Five of the bands were histone kinases and gave little activity with nonhistone proteins. Two bands gave their greatest activity with phosvitin or casein. Protamine and arginine-rich histone were particularly good substrates for the two remaining bands. The activity in each band exhibited a different and distinct pattern of ontogenic development, which was not affected by the nature of the protein used for the assay. There was a reasonable similarity between the overall developmental profile for the rate of phosphorylation of each substrate calculated from the sum of activities determined on the individual bands and the profile directly determined in the whole soluble fraction.Both the direct assay and the electrophoretic results indicate that brown fat contains a number of protein kinase activities that can be distinguished by their specificities for protein substrate and by the pattern of changes in their activities during development. There were three main patterns of ontogenic changes in activity: one decreased progressively from high values in late foetuses; the second showed a marked fall in activity during the 3rd week after birth; and in the third, the activity rose after birth and then remained constant. The greatest changes in kinase activity thus occur during the periods when there are pronounced changes in the rates of proliferation and differentiation in brown fat, in its capacity to produce heat, and in the diet of the animal. It seems possible that the different types of protein kinase carry out phosphorylations involved in the regulation of different processes in brown fat.

The Saccharomyces cerevisiae YAK1 gene encodes a protein kinase that is induced by arrest early in the cell cycle

1991 ◽  
Vol 11 (8) ◽  
pp. 4045-4052
Author(s):  
S Garrett ◽  
M M Menold ◽  
J R Broach
Keyword(s):  
Cell Cycle ◽  
Protein Kinase ◽  
Kinase Activity ◽  
Specific Activity ◽  
S Phase ◽  
Protein Kinase Activity ◽  
Dependent Protein Kinase ◽  
Protein Levels ◽  
Cycle Arrest ◽  
Dependent Protein

Null mutations in the gene YAK1, which encodes a protein with sequence homology to known protein kinases, suppress the cell cycle arrest phenotype of mutants lacking the cyclic AMP-dependent protein kinase (A kinase). That is, loss of the YAK1 protein specifically compensates for loss of the A kinase. Here, we show that the protein encoded by YAK1 has protein kinase activity. Yak1 kinase activity is low during exponential growth but is induced at least 50-fold by arrest of cells prior to the completion of S phase. Induction is not observed by arrest at stages later in the cell cycle. Depending on the arrest regimen, induction can occur either by an increase in Yak1 protein levels or by an increase in Yak1 specific activity. Finally, an increase in Yak1 protein levels causes growth arrest of cells with attenuated A kinase activity. These results suggest that Yak1 acts in a pathway parallel to that of the A kinase to negatively regulate cell proliferation.

Effect of Thrombin on Phosphorylation of Platelet Membrane Proteins

1976 ◽  
Vol 35 (03) ◽  
pp. 635-642 ◽  
Author(s):  
M Steiner
Keyword(s):  
Protein Kinase ◽  
Kinase Activity ◽  
Qualitative Change ◽  
Protein Kinase Activity ◽  
Protein Substrates ◽  
Phosphoprotein Phosphatase ◽  
Progressive Loss ◽  
Platelet Membranes ◽  
Endogenous Protein ◽  
Considerable Loss

SummaryThe effect of thrombin on the phosphorylating activity of platelet membranes was compared to that of trypsin. Preincubation of non-32P phosphorylated platelet membranes with or without either of these two enzymes resulted in a considerable loss of membrane protein kinase activity which was most severe when trypsin was used. Protein kinase activity and endogenous protein acceptors decreased in parallel. 32P-phosphorylated membranes showed a slow but progressive loss of label which was accelerated by trypsin. Thrombin under these conditions prevented the loss of 32P-phosphate. These results are interpreted to indicate a thrombin-induced destruction of a phosphoprotein phosphatase. The protein kinase activity of phosphorylated platelet membranes using endogenous or exogenous protein substrates showed a significant reduction compared to non-phosphorylated membranes suggesting a deactivation of protein kinase by phosphorylation of platelet membranes. Neither thrombin nor trypsin caused a qualitative change in the membrane polypeptides accepting 32P-phosphate but resulted in quantitative alterations of their ability to become phosphorylated.

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