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Protein kinase C subtypes in human neutrophils
D Obel1, L H Rasmussen, N O Christiansen
1Department of Medicine and Infectious Diseases, Marselisborg Hospital, University of Aarhus, Denmark.
Summary
Researchers isolated protein kinase C (PKC) from rat brain and human neutrophils using HPLC. Human neutrophils primarily express types II and III PKC, with type II translocating to membranes upon stimulation.
Area of Science:
- Biochemistry
- Cell Biology
- Molecular Biology
Background:
- Protein kinase C (PKC) is a family of enzymes involved in cellular signaling.
- Different isoforms of PKC exist with varying tissue distribution and functions.
- Understanding PKC isoform expression and regulation is crucial for comprehending cellular responses.
Purpose of the Study:
- To chromatographically separate and identify protein kinase C (PKC) isoforms in rat brain and human neutrophils.
- To investigate the distribution and translocation of PKC isoforms in human neutrophils upon stimulation.
Main Methods:
- High-performance liquid chromatography (HPLC) with hydroxylapatite column chromatography was used for protein separation.
- Rat brain and human neutrophil lysates were analyzed.
- Stimulation of human neutrophils was induced using phorbolmyristatacetate (PMA).
Main Results:
- Rat brain yielded three PKC types (I, II, and III).
- Human neutrophils exhibited two PKC types, corresponding to types II and III found in the brain.
- Type III was predominant in unstimulated neutrophils, while type II translocated to membranes upon PMA stimulation.
- Both identified neutrophil PKC types showed equivalent activation by phosphatidylserine, diolein, and magnesium, with identical Km for ATP.
Conclusions:
- Human neutrophils express at least two major PKC isoforms (II and III).
- PKC isoform distribution and translocation are regulated by cellular stimulation.
- The characterized PKC isoforms in neutrophils share similar activation kinetics and cofactor requirements.