Modulation of the Respiratory Burst

Protein kinase C represents a family of more than 11 phospholipid-dependent serine/threonine kinases that are involved in a variety of pathways that regulate cell growth, death, and stress responsiveness. 

Protein kinases C transduce the of signals mediated by phospholipid hydrolysis. Activation of G protein coupled receptors, tyrosine kinase receptors, and nonreceptor tyrosine kinases can activate protein kinase C, by stimulation of either phospholipases C to yield diacylglycerol or phospholipase D to yield phosphatidic acid and then diacylglycerol. Phospholipase D has been implicated in the process of generation of reactive oxygen species by neutrophil granulocytes (for review see Exton 2002, p. 53). 

The isoenzymes of protein kinase C fall into three subclasses according to their dependence on Ca for activation. The Ca -dependent group includes PKC subtypes a. Pi, Pn, and y, and the Ca -independent group includes PKC subtypes 8, e, e, T), and . The regulation of the atypical subtypes i, and X has not been clearly estabhshed, although their activities are stimulated by phosphatidylser-ine. Protein kinase p, (human) and its murine ho-mologue, protein kinase D, form a distinct class in that the kinase core is actually most similar to that of the calmodulin-dependent kinases and no pseu- 

The atypical protein kinase is ubiquitously expressed. It is considered atypical in that it is not activated by diacylglycerol or pre-treatment with phorbol esters. In addition, the protein does not undergo translocation from cytosol to membrane when activated. Phosphatidylinositol 3,4,5-triphosphate has been shown to result in a large stimulation of protein kinase t, (Nakanishi et al. 1993). 

Ischaemic preconditioning of the rabbit heart caused selective translocation of the 8 and iso- 

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Gibson-Berry, K. L., Whitin, J. C., and Cohen, H. J., 1993, Modulation of the respiratory burst in human neutrophils by isoproterenol and dibutyryl cyclic AMP, J. Neuroimmunol. 43 59-68. 

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