scholarly journals Immunofluorescent localization of cyclic nucleotide-dependent protein kinases on the mitotic apparatus of cultured cells.

1980 ◽  
Vol 87 (2) ◽  
pp. 336-345 ◽  
Author(s):  
C L Browne ◽  
A H Lockwood ◽  
J L Su ◽  
J A Beavo ◽  
A L Steiner

Cyclic nucleotides and cyclic nucleotide-dependent protein kinases have been implicated in the regulation of cell motility and division, processes that depend on the cell cytoskeleton. To determine whether cyclic nucleotides or their kinases are physically associated with the cytoskeleton during cell division, fluorescently labeled antibodies directed against cyclic AMP, cyclic GMP, and the cyclic nucleotide-dpendent protein kinases were used to localize these molecules in mitotic PtK1 cells. Both the cyclic GMP-dependent protein kinase and the type II regulatory subunit of the cyclic AMP-dependent protein kinase were localized on the mitotic spindle. Throughout mitosis, their distribution closely resembled that of tubulin. Antibodies to cyclic AMP, cyclic GMP, and the type I regulatory and catalytic subunits of the cyclic AMP-dependent protein kinase did not label the mitotic apparatus. The association between specific components of the cyclic neucleotide system and the mitotic spindle suggests that cyclic nucleotide-dependent phosphorylation of spindle proteins, such as those of microtubules, may play a fundamental role in the regulation of spindle assembly and chromosome motion.

1990 ◽  
Vol 95 (2) ◽  
pp. 219-230
Author(s):  
N.M. Bonini ◽  
D.L. Nelson

Permeabilized, MgATP-reactivated cells of Paramecium (models) respond to cyclic AMP and cyclic GMP by increasing forward swimming speed. In association with the motile response, cyclic AMP and 8-bromo-cyclic GMP (8-Br-cyclic GMP) stimulated protein phosphorylation. Cyclic AMP addition to permeabilized cells reproducibly stimulated the phosphorylation of 10 proteins, ranging in molecular weight from 15 to 110K (K = 10(3) Mr). 8-Br-cyclic GMP, which selectively activates the cyclic GMP-dependent protein kinase of Paramecium, stimulated the phosphorylation of a subset of the proteins phosphorylated by cyclic AMP. Ca2+ addition caused backward swimming and stimulated the phosphorylation of four substrates, including a 25K target that may also be phosphorylated in response to cyclic nucleotide addition. Ba2+ and Sr2+ also induced backward swimming, but did not cause detectable phosphorylation. To identify ciliary targets of cyclic nucleotide-dependent protein kinase activity, permeabilized cells were deciliated following reactivation of motility with Mg-[gamma-32P]ATP in the presence or absence of cyclic nucleotide. Soluble proteins of the deciliation supernatant were enriched in 15 cyclic AMP-stimulated phosphoproteins, ranging in molecular weight from 15 to 95K. Most of the ciliary substrates were axonemal and could be released by high salt solution. A 29K protein that copurified in sucrose gradients with the 22S dynein, and a high molecular weight protein (greater than 300K) in the 19 S region were phosphorylated when cyclic AMP was added to permeabilized, motile cells. These data suggest that regulation of ciliary motility by cyclic AMP may include phosphorylation of dynein-associated proteins.


1983 ◽  
Vol 213 (1) ◽  
pp. 159-164 ◽  
Author(s):  
D B Glass

The peptide Arg-Lys-Arg-Ala-Arg-Lys-Glu was synthesized and tested as an inhibitor of cyclic GMP-dependent protein kinase. This synthetic peptide is a non-phosphorylatable analogue of a substrate peptide corresponding to a phosphorylation site (serine-32) in histone H2B. The peptide was a competitive inhibitor of cyclic GMP-dependent protein kinase with respect to synthetic peptide substrates, with a Ki value of 86 microM. However, it did not inhibit phosphorylation of intact histones by cyclic GMP-dependent protein kinase under any conditions tested. Arg-Lys-Arg-Ala-Arg-Lys-Glu competitively inhibited the phosphorylation of either peptides or histones by the catalytic subunit of cyclic AMP-dependent protein kinase, with similar Ki values (550 microM) for both of these substrates. The peptide Leu-Arg-Arg-Ala-Ala-Leu-Gly, which was previously reported to be a selective inhibitor of both peptide and histone phosphorylation by cyclic AMP-dependent protein kinase, was a poor inhibitor of cyclic GMP-dependent protein kinase acting on peptide substrates (Ki = 800 microM), but did not inhibit phosphorylation of histones by cyclic GMP-dependent protein kinase. The selectivity of these synthetic peptide inhibitors toward either cyclic GMP-dependent or cyclic AMP-dependent protein kinases is probably based on differences in the determinants of substrate specificity recognized by these two enzymes. It is concluded that histones interact differently with cyclic GMP-dependent protein kinase from the way they do with the catalytic subunit of cyclic AMP-dependent protein kinase.


1990 ◽  
Vol 10 (12) ◽  
pp. 6775-6780 ◽  
Author(s):  
S Beushausen ◽  
H Bayley

Transcripts encoding CAPL-B, an apparent member of the cyclic-nucleotide-regulated kinase subfamily in Aplysia californica, are found exclusively in the ovotestis and are concentrated in meiotic and postmeiotic spermatogenic cells. The CAPL-B polypeptide is present in mature spermatozoa, suggesting that the kinase plays a part in regulating events associated with fertilization.


1999 ◽  
Vol 82 (3) ◽  
pp. 1577-1589 ◽  
Author(s):  
Linda Santschi ◽  
Magali Reyes-Harde ◽  
Patric K. Stanton

Although it is widely agreed that cyclic AMP is necessary for the full expression of long-term potentiation of synaptic strength, it is unclear whether cyclic AMP or cyclic AMP-dependent protein kinase (PKA) play roles in the induction of long-term depression (LTD). We show here that two PKA inhibitors, H-89 (10 μM) and KT5720 (1 μM), are unable to block induction of LTD at Schaffer collateral-CA1 synapses in hippocampal slices in vitro. Rather, H-89 enhanced the magnitude of LTD induced by submaximal low-frequency stimulation. Raising [cGMP] with zaprinast (20 μM), a selective type V phosphodiesterase inhibitor, reversibly depressed synaptic potentials. However, coapplication of H-89 plus zaprinast converted this to a robust LTD that depended critically on activation of cyclic GMP-dependent protein kinase (PKG). Chemically induced LTD is activity-independent because it could be induced without stimulation and in tetrodotoxin (0.5 μM). Additionally, chemical LTD did not require activation of N-methyl-d-aspartate or GABA receptors and could be reversed by LTP. Stimulus-induced LTD occluded chemical LTD, suggesting a common expression mechanism. In contrast to bath application, postsynaptic infusion of H-89 into CA1 pyramidal neurons did not enhance LTD, suggesting a presynaptic site of action. Further evidence for a presynaptic locus was supplied by experiments where H-89 applied postsynaptically along with bath application of zaprinast was unable to produce chemical LTD. Thus simultaneous presynaptic generation of cyclic GMP and inhibition of PKA is sufficient to induce LTD of synaptic transmission at Schaffer collateral-CA1 synapses.


2014 ◽  
Vol 106 (2) ◽  
pp. 658a
Author(s):  
James Campbell ◽  
Gilbert Huang ◽  
Albert Reger ◽  
Todd Link ◽  
John Ladbury ◽  
...  

1980 ◽  
Vol 192 (1) ◽  
pp. 223-230 ◽  
Author(s):  
G Schwoch ◽  
A Hamann ◽  
H Hilz

An antiserum against the catalytic subunit C of cyclic AMP-dependent protein kinase, isolated from bovine heart type II protein kinase, was produced in rabbits. Reaction of the catalytic subunit with antiserum and separation of the immunoglobulin G fraction by Protein A-Sepharose quantitatively removed the enzyme from solutions. Comparative immunotitration of protein kinases showed that the amount of antiserum required to eliminate 50% of the enzymic activity was identical for pure catalytic subunit, and for holoenzymes type I and type II. The reactivity of the holoenzymes with the antiserum was identical in the absence or the presence of dissociating concentrations of cyclic AMP. Most of the holoenzyme (type II) remains intact when bound to the antibodies as shown by quantification of the regulatory subunit in the supernatant of the immunoprecipitate. Titration with the antibodies also revealed the presence of a cyclic AMP-independent histone kinase in bovine heart protein kinase I preparations obtained by DEAE-cellulose chromatography. Cyclic AMP-dependent protein kinase purified from the particulate fraction of bovine heart reacted with the antiserum to the same degree as the soluble enzyme, whereas two cyclic AMP-independent kinases separated from the particle fraction neither reacted with the antiserum nor influenced the reaction of the antibodies with the cyclic AMP-dependent protein kinase. Immunotitration of the protein kinase catalytic subunit C from rat liver revealed that the antibodies had rather similar reactivities towards the rat liver and the bovine heart enzyme. This points to a relatively high degree of homology of the catalytic subunit in mammalian tissues and species. Broad applicability of the antiserum to problems related to cyclic AMP-dependent protein kinases is thus indicated.


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