Identification of an endogenous protein kinase C activity and its intrinsic 15-kilodalton substrate in purified canine cardiac sarcolemmal vesicles

C. F. Presti, B. T. Scott, Larry Jones

Research output: Contribution to journalArticle

68 Citations (Scopus)

Abstract

The cardiac sarcolemmal 15-kDa protein, previously shown to be the principal sarcolemmal substrate phosphorylated in intact heart in response to β-adrenergic stimulation, was demonstrated to be the major substrate phosphorylated in purified canine cardiac sarcolemmal vesicles by an intrinsic protein kinase C activity. The intrinsic protein kinase C, detected by its ability to phosphorylate H1 histones, was most concentrated in cardiac sarcolemmal vesicles and absent from sarcoplasmic reticulum membranes. Unmasking techniques localized the intrinsic protein kinase activity and its principal endogenous substrate, the 15-kDa protein, to the cytoplasmic surfaces of sarcolemmal vesicles; phospholamban contaminating the sarcolemmal preparation was not significantly phosphorylated. The intrinsic protein kinase C required micromolar Ca2+ for activity, but not calmodulin. Half-maximal phosphorylation of the 15-kDa protein occurred at 10 μM Ca2+; optimal phosphorylation of the 15-kDa protein by protein kinase C and Ca2+ was additive to that produced by cAMP-dependent protein kinase. Exogenous phospholipids were not required to activate endogenous protein kinase C. However, heat-treated sarcolemmal vesicles, in which intrinsic protein kinase activities were inactivated, were sufficient to maximally activate soluble protein kinase C prepared from rat brain, suggesting that all the necessary phospholipid cofactors were already present in sarcolemmal vesicles. Of the many proteins present in sarcolemmal vesicles, only the 15-kDa protein was phosphorylated significantly in heat-inactivated sarcolemmal vesicles by soluble protein kinase C, confirming that the 15-kDa protein was a preferential substrate for this enzyme. Consistent with a protein kinase C activity in sarcolemmal vesicles, the tumor-promoting phorbol ester 12-O-tetradecanoylphorbol 13-acetate stimulated 15-kDa protein phosphorylation severalfold, producing approximately 70% of the maximal phosphorylation even in the absence of significant ionized Ca2+. The results are compatible with an intrinsic protein kinase C activity in sarcolemmal vesicles whose major substrate is the 15-kDa protein.

Original languageEnglish
Pages (from-to)13879-13889
Number of pages11
JournalJournal of Biological Chemistry
Volume260
Issue number25
StatePublished - 1985

Fingerprint

Protein Kinase C
Canidae
Phosphorylation
Substrates
Proteins
Protein Kinases
Phospholipids
Hot Temperature
Sarcoplasmic Reticulum
Phorbol Esters
Tetradecanoylphorbol Acetate
Calmodulin
Cyclic AMP-Dependent Protein Kinases
Adrenergic Agents
Histones
Rats
Tumors
Brain
Acetates
Membranes

ASJC Scopus subject areas

  • Biochemistry

Cite this

Identification of an endogenous protein kinase C activity and its intrinsic 15-kilodalton substrate in purified canine cardiac sarcolemmal vesicles. / Presti, C. F.; Scott, B. T.; Jones, Larry.

In: Journal of Biological Chemistry, Vol. 260, No. 25, 1985, p. 13879-13889.

Research output: Contribution to journalArticle

@article{975b2be83e0e40398282489fe5e0f7e8,
title = "Identification of an endogenous protein kinase C activity and its intrinsic 15-kilodalton substrate in purified canine cardiac sarcolemmal vesicles",
abstract = "The cardiac sarcolemmal 15-kDa protein, previously shown to be the principal sarcolemmal substrate phosphorylated in intact heart in response to β-adrenergic stimulation, was demonstrated to be the major substrate phosphorylated in purified canine cardiac sarcolemmal vesicles by an intrinsic protein kinase C activity. The intrinsic protein kinase C, detected by its ability to phosphorylate H1 histones, was most concentrated in cardiac sarcolemmal vesicles and absent from sarcoplasmic reticulum membranes. Unmasking techniques localized the intrinsic protein kinase activity and its principal endogenous substrate, the 15-kDa protein, to the cytoplasmic surfaces of sarcolemmal vesicles; phospholamban contaminating the sarcolemmal preparation was not significantly phosphorylated. The intrinsic protein kinase C required micromolar Ca2+ for activity, but not calmodulin. Half-maximal phosphorylation of the 15-kDa protein occurred at 10 μM Ca2+; optimal phosphorylation of the 15-kDa protein by protein kinase C and Ca2+ was additive to that produced by cAMP-dependent protein kinase. Exogenous phospholipids were not required to activate endogenous protein kinase C. However, heat-treated sarcolemmal vesicles, in which intrinsic protein kinase activities were inactivated, were sufficient to maximally activate soluble protein kinase C prepared from rat brain, suggesting that all the necessary phospholipid cofactors were already present in sarcolemmal vesicles. Of the many proteins present in sarcolemmal vesicles, only the 15-kDa protein was phosphorylated significantly in heat-inactivated sarcolemmal vesicles by soluble protein kinase C, confirming that the 15-kDa protein was a preferential substrate for this enzyme. Consistent with a protein kinase C activity in sarcolemmal vesicles, the tumor-promoting phorbol ester 12-O-tetradecanoylphorbol 13-acetate stimulated 15-kDa protein phosphorylation severalfold, producing approximately 70{\%} of the maximal phosphorylation even in the absence of significant ionized Ca2+. The results are compatible with an intrinsic protein kinase C activity in sarcolemmal vesicles whose major substrate is the 15-kDa protein.",
author = "Presti, {C. F.} and Scott, {B. T.} and Larry Jones",
year = "1985",
language = "English",
volume = "260",
pages = "13879--13889",
journal = "Journal of Biological Chemistry",
issn = "0021-9258",
publisher = "American Society for Biochemistry and Molecular Biology Inc.",
number = "25",

}

TY - JOUR

T1 - Identification of an endogenous protein kinase C activity and its intrinsic 15-kilodalton substrate in purified canine cardiac sarcolemmal vesicles

AU - Presti, C. F.

AU - Scott, B. T.

AU - Jones, Larry

PY - 1985

Y1 - 1985

N2 - The cardiac sarcolemmal 15-kDa protein, previously shown to be the principal sarcolemmal substrate phosphorylated in intact heart in response to β-adrenergic stimulation, was demonstrated to be the major substrate phosphorylated in purified canine cardiac sarcolemmal vesicles by an intrinsic protein kinase C activity. The intrinsic protein kinase C, detected by its ability to phosphorylate H1 histones, was most concentrated in cardiac sarcolemmal vesicles and absent from sarcoplasmic reticulum membranes. Unmasking techniques localized the intrinsic protein kinase activity and its principal endogenous substrate, the 15-kDa protein, to the cytoplasmic surfaces of sarcolemmal vesicles; phospholamban contaminating the sarcolemmal preparation was not significantly phosphorylated. The intrinsic protein kinase C required micromolar Ca2+ for activity, but not calmodulin. Half-maximal phosphorylation of the 15-kDa protein occurred at 10 μM Ca2+; optimal phosphorylation of the 15-kDa protein by protein kinase C and Ca2+ was additive to that produced by cAMP-dependent protein kinase. Exogenous phospholipids were not required to activate endogenous protein kinase C. However, heat-treated sarcolemmal vesicles, in which intrinsic protein kinase activities were inactivated, were sufficient to maximally activate soluble protein kinase C prepared from rat brain, suggesting that all the necessary phospholipid cofactors were already present in sarcolemmal vesicles. Of the many proteins present in sarcolemmal vesicles, only the 15-kDa protein was phosphorylated significantly in heat-inactivated sarcolemmal vesicles by soluble protein kinase C, confirming that the 15-kDa protein was a preferential substrate for this enzyme. Consistent with a protein kinase C activity in sarcolemmal vesicles, the tumor-promoting phorbol ester 12-O-tetradecanoylphorbol 13-acetate stimulated 15-kDa protein phosphorylation severalfold, producing approximately 70% of the maximal phosphorylation even in the absence of significant ionized Ca2+. The results are compatible with an intrinsic protein kinase C activity in sarcolemmal vesicles whose major substrate is the 15-kDa protein.

AB - The cardiac sarcolemmal 15-kDa protein, previously shown to be the principal sarcolemmal substrate phosphorylated in intact heart in response to β-adrenergic stimulation, was demonstrated to be the major substrate phosphorylated in purified canine cardiac sarcolemmal vesicles by an intrinsic protein kinase C activity. The intrinsic protein kinase C, detected by its ability to phosphorylate H1 histones, was most concentrated in cardiac sarcolemmal vesicles and absent from sarcoplasmic reticulum membranes. Unmasking techniques localized the intrinsic protein kinase activity and its principal endogenous substrate, the 15-kDa protein, to the cytoplasmic surfaces of sarcolemmal vesicles; phospholamban contaminating the sarcolemmal preparation was not significantly phosphorylated. The intrinsic protein kinase C required micromolar Ca2+ for activity, but not calmodulin. Half-maximal phosphorylation of the 15-kDa protein occurred at 10 μM Ca2+; optimal phosphorylation of the 15-kDa protein by protein kinase C and Ca2+ was additive to that produced by cAMP-dependent protein kinase. Exogenous phospholipids were not required to activate endogenous protein kinase C. However, heat-treated sarcolemmal vesicles, in which intrinsic protein kinase activities were inactivated, were sufficient to maximally activate soluble protein kinase C prepared from rat brain, suggesting that all the necessary phospholipid cofactors were already present in sarcolemmal vesicles. Of the many proteins present in sarcolemmal vesicles, only the 15-kDa protein was phosphorylated significantly in heat-inactivated sarcolemmal vesicles by soluble protein kinase C, confirming that the 15-kDa protein was a preferential substrate for this enzyme. Consistent with a protein kinase C activity in sarcolemmal vesicles, the tumor-promoting phorbol ester 12-O-tetradecanoylphorbol 13-acetate stimulated 15-kDa protein phosphorylation severalfold, producing approximately 70% of the maximal phosphorylation even in the absence of significant ionized Ca2+. The results are compatible with an intrinsic protein kinase C activity in sarcolemmal vesicles whose major substrate is the 15-kDa protein.

UR - http://www.scopus.com/inward/record.url?scp=0022402480&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0022402480&partnerID=8YFLogxK

M3 - Article

VL - 260

SP - 13879

EP - 13889

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 25

ER -