Partial Characterization of Protein Kinase C and Inhibitor Activity of Protein Kinase C in Rabbit Peritoneal Neutrophils

Huang, Chi‐Kuang; Oshana, Scott

doi:10.1002/jlb.39.6.671

Cited by 17 publications

(3 citation statements)

References 19 publications

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“…It is not known if PKC-I binds to phosphatidylserine-containing vesicles, but preliminary results (not shown) from our laboratory suggest that PKC-I binding to PKC prevents its association with phosphatidylserine. Second, a soluble PKC inhibitor from rabbit peritoneal neutrophils has a reported molecular mass of 67 kDa [31]. Finally, the low-molecular-mass antibiotic peptides known as defensins HNP-1, HNP-2 and HNP-3 (< 3.5 kDa) all inhibited PKC non-competitively with respect to cofactors, ATP and substrate [21].…”

Section: Discussionmentioning

confidence: 99%

“…We [29] and others [30][31][32] have previously described endogenous inhibitors of PKC which may modulate PKC activity and thereby certain cellular functional events in vivo. The neutrophil PKC inhibitor, PKC-I, is heat-and proteinasesensitive, is not itself a proteinase, and appears to be present primarily in the membrane fraction of specific granules and in the plasma-membrane fraction [29].…”

Section: Introductionmentioning

confidence: 99%

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Purification of PKC-I, an endogenous protein kinase C inhibitor, and types II and III protein kinase C isoenzymes from human neutrophils

Balazovich

McEwen

Lutzke

et al. 1992

Biochemical Journal

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Human neutrophil protein kinase C (PKC) activity is inhibited by an endogenous protein found primarily in the pellet fraction from homogenized specific granules, which was both heat- and proteinase-sensitive [Balazovich, Smolen & Boxer (1986) J. Immunol. 137, 1665-1673]. We now report that two PKC isoenzymes and the endogenous PKC inhibitor, which we named PKC-I, were purified from human neutrophils. A neutrophil soluble fraction that was subjected to DEAE-Sephacel chromatography yielded highly enriched PKC because, by definition, enzymic activity was strictly dependent on Ca2+ and phosphatidylserine. Hydroxyapatite chromatography resolved two peaks of PKC activity. Type II and Type III PKC isoenzymes were each identified on Western blots by using isoenzyme-specific monoclonal antibodies. Unlike rat brain, from which PKC isoenzymes were also purified, Type I PKC was not detected in human neutrophils. Western blots indicated that both Type II and Type III PKC isoenzymes had molecular masses near 80 kDa. In agreement with other reports, PKC was autophosphorylated in vitro. PKC-I, an endogenous neutrophil inhibitor of PKC, was purified to apparent homogeneity by DEAE-Sephacel and S-400 Sephacel chromatography. PKC-I had a molecular mass of 41 kDa. PKC-I inhibited purified PKC activity stimulated by 1,2-diacylglycerols in a concentration-dependent manner, and inhibited PKC-dependent phosphorylation of proteins present in neutrophil cytosol.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Purification of PKC-I, an endogenous protein kinase C inhibitor, and types II and III protein kinase C isoenzymes from human neutrophils

Balazovich

McEwen

Lutzke

et al. 1992

Biochemical Journal

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“…We have shown that PKC activity in cytosolic preparations of the ovary of the pseudopregnant and pregnant rat is masked by an endogenous inhibitor of PKC [6][7][8], and we have recently demonstrated that this PKC-inhibitory factor in the rat ovary is a protein phosphatase [9]. Endogenous inhibitors have been identified in other tissues [10][11][12][13][14][15][16]. To date, only one of these has been shown to be a protein phosphatase [16].…”

Section: Introductionmentioning

confidence: 98%

Endogenous Modulation of Protein Kinase C in the Rhesus Monkey Corpus Luteum1

Eyster

1994

Biology of Reproduction

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The activity of protein kinase C (PKC) and the presence of endogenous PKC-modulatory factors in monkey CL have not been previously reported. The specific activity of Ca(2+)- and lipid-dependent PKC activity in cytosols prepared from CL obtained from rhesus monkeys at midluteal phase was 515.1 +/- 79 pmol/min x mg; Ca(2+)-independent PKC activity was 233.2 +/- 31 pmol/min x mg. No PKC-inhibitory activity was seen when luteal cytosol was mixed with a control preparation of PKC (control PKC 10.2 +/- 2.0 pmol/min; luteal cytosol plus control PKC 26.0 +/- 2.1 pmol/min). However, the monkey CL contained PKC-phosphatase activity (the endogenous inhibitor of PKC in the rat ovary is a protein phosphatase). Specific activity of luteal PKC phosphatase activity was 609.0 +/- 94 pmol/min x mg. Kinetic studies suggested that the monkey CL contained a competitive inhibitor of the phosphatase. Heat-treated cytosol mixed with control PKC (9.0 +/- 0.7 pmol/min) resulted in enzyme activity that was significantly greater than that of the control (13.7 +/- 1.2 pmol/min). Luteal cytosol that had been heat-treated and extracted with petroleum ether substituted for lipids in the activation of PKC. In summary, the activity of PKC in the monkey CL was readily measurable; it was not masked by an endogenous PKC-inhibitory factor. The monkey CL did contain a heat-stable PKC-stimulatory activity.

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Presence of an Endogenous Inhibitor of Protein Kinase C Throughout Pseudopregnancy in the Rat Ovary

Eyster¹

1991

Signaling Mechanisms and Gene Expression in the Ovary

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Partial Characterization of Protein Kinase C and Inhibitor Activity of Protein Kinase C in Rabbit Peritoneal Neutrophils

Cited by 17 publications

References 19 publications

Purification of PKC-I, an endogenous protein kinase C inhibitor, and types II and III protein kinase C isoenzymes from human neutrophils

Purification of PKC-I, an endogenous protein kinase C inhibitor, and types II and III protein kinase C isoenzymes from human neutrophils

Endogenous Modulation of Protein Kinase C in the Rhesus Monkey Corpus Luteum1

Presence of an Endogenous Inhibitor of Protein Kinase C Throughout Pseudopregnancy in the Rat Ovary

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