Calcium-activated, phospholipid-dependent protein kinase (protein kinase C): general aspects and experimental considerations.

Calcium-activated, phospholipid-dependent protein kinase (protein kinase C) is a ubiquitous serine and threonine protein kinase that has been implicated in the regulation of a wide variety of cellular functions. Protein kinase C is tightly linked to signal transduction through phosphatidylinositol turnover, and interacts with the cAMP-protein kinase A pathway in either a "monodirectional" or "bidirectional" mode. The discovery and development of protein kinase C inhibitors and activators offer useful tools to investigate the role of the kinase in specific cellular functions. However, caution should be exercised in interpreting the results of these studies, with special attention directed at experimental design. The present review summarizes some of the general aspects of protein kinase C. Methodological considerations for planning experiments and interpretation of results are described. In addition, we present some examples for the role of protein kinase C in the pathogenesis of disease.