Kinase

Cell biology

Diacylglycerol kinase

Molecular biology

Biology

Calcium

Cytosol

Calcium in biology

Literature

Receptor

Biochemistry

Intracellular

Combinatorial chemistry

Organic chemistry

Membrane

Ionophore

Concanavalin A

Protein kinase C

In vitro

Tetradecanoylphorbol Acetate

Macrophage

Enzyme

Phorbol

Activator (genetics)

Chemistry

Dual (grammatical number)

Dual role

Superoxide

Biochimica et Biophysica Acta (BBA) - Molecular Cell Research

Superoxide production in alveolar macrophages is stimulated by agonists which act through Ca2+-mediated (concanavalin A) and/or protein kinase C (phorbol ester or diacylglycerol analogues) -mediated events. Simultaneous addition of saturating concentrations of concanavalin A and a protein kinase C activator (either phorbol 12-myristate-13-acetate or 1-oleoyl-2-acetyl-sn-glycerol) caused a supra-additive enhancement of the initial rate of O⨪2 production. This synergism closely correlated with the known time-course of Ca2+ mobilization induced by concanavalin A; however, it occurred under conditions in which protein kinase C activation is reportedly not Ca2+ dependent. Phorbol ester-induced O⨪2 production was partially inhibited by the Ca2+ ionophore, A23187. Although phorbol ester-stimulated O⨪2 production initially was enhanced by concanavalin A, the duration of this O⨪2 production was reduced in comparison to that induced by phorbol ester alone. These results suggest a dual role for intracellular Ca2+ in both stimulatory and inhibitory regulation of O⨪2 production.

A dual role for calcium in regulation of superoxide generation by stimulated rat alveolar macrophages