The inhibitor protein of the cyclic AMP-dependent protein kinase-catalytic subunit interaction. Composition of multiple complexes

It has been previously demonstrated that the combination of pure preparations of the inhibitor protein of the cyclic AMP-dependent protein kinase and the catalytic subunit of this enzyme resulted in the formation of multiple complexes [Van Patten, Fletcher & Walsh (1986) J. Biol. Chem. 261, 5514-5523]. In the present study it is demonstrated that these multiple species occur because the bovine heart protein kinase preparation contains multiple forms of catalytic subunit [Kinzel, Hotz, König, Gagelmann, Pyerin, Reed, Köbler, Hofmann, Obst, Gensheimer, Goldblatt & Shaltiel (1987) Arch. Biochem. Biophys. 253, 341-349].

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Antiserum against the catalytic subunit of adenosine 3′:5′-cyclic monophosphate-dependent protein kinase. Reactivity towards various protein kinases

Biochemical Journal ◽

10.1042/bj1920223 ◽

1980 ◽

Vol 192 (1) ◽

pp. 223-230 ◽

Cited By ~ 31

Author(s):

G Schwoch ◽

A Hamann ◽

H Hilz

Keyword(s):

Protein Kinase ◽

Cyclic Amp ◽

Protein Kinases ◽

Rat Liver ◽

Catalytic Subunit ◽

Type Ii ◽

Dependent Protein Kinase ◽

Subunit C ◽

Bovine Heart ◽

Dependent Protein

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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Association of cyclic-AMP-dependent protein kinase with neurofilaments

Biochemical Journal ◽

10.1042/bj2820477 ◽

1992 ◽

Vol 282 (2) ◽

pp. 477-481 ◽

Cited By ~ 24

Author(s):

A Dosemeci ◽

H C Pant

Keyword(s):

Protein Kinase ◽

Cyclic Amp ◽

Kinase Activity ◽

Inhibitory Effect ◽

Catalytic Subunit ◽

Regulatory Subunit ◽

Dependent Manner ◽

Dependent Protein Kinase ◽

Bovine Heart ◽

Dependent Protein

Neurofilament preparations isolated from bovine spinal cord contain cyclic-AMP-dependent protein kinase (PKA) activity. Treatment of this preparation with cyclic AMP, to dissociate the regulatory subunit of the kinase from the catalytic subunit, resulted in retention of the kinase activity but loss of cyclic AMP regulation. This suggests that PKA is associated via its catalytic subunit with the neurofilament preparation. The association of exogenous PKA from bovine heart with the neurofilament preparation and with neurofilaments reconstituted from purified neurofilament proteins was also investigated. Either the free catalytic subunit or combinations of the catalytic and regulatory subunits of PKA were incubated with the preparations, and the degree of association was determined as the level of kinase activity that co-sediments with neurofilaments. The results indicate that the free catalytic subunit of PKA co-sediments with neurofilaments reconstituted from purified proteins. The regulatory subunit of PKA from bovine heart, when pre-mixed with the catalytic subunit, decreased the level of kinase that co-sediments with the neurofilament fraction in a dose-dependent manner. This effect of the regulatory subunit was reversed by inclusion of cyclic AMP in the incubation medium before centrifugation. The above findings suggest that the regulatory subunit, when attached to the catalytic subunit, has an inhibitory effect on its association with neurofilaments, with the implication that the association may be a cyclic-AMP-regulated event.

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