Modulation of protein kinase C activity in Plasmodium falciparum- infected
erythrocytes
BS Hall, OO Daramola, G Barden and GA Targett
Department of Medical Parasitology, London School of Hygiene and Tropical
Medicine, UK.
Infection of human erythrocytes with the malaria parasite Plasmodium
falciparum induces many morphological and biochemical changes in the host
cell. Host serine/threonine protein kinases could be involved in some of
these processes. The aim of this study was to determine the effect of
infection on red blood cell protein kinase C (PKC) and establish the
importance of this enzyme in parasite growth and sexual stage
differentiation. Phorbol myristate acetate (PMA)-induced translocation of
erythrocyte PKC activity is impaired in erythrocytes enriched for mature
asexual stage infected cells. Western blotting shows that this is due to a
relative reduction in membrane PKC protein levels rather than inhibition of
enzyme activity and analysis of PKC activity isolated from whole cell
lysates by DE52 chromatography suggests that total activatable PKC levels
are lower in infected erythrocytes. A reduction in PMA-induced activation
is also observed in PKC assays performed in situ. Downregulation of
erythrocyte PKC by overnight incubation with PMA before infection causes a
significant decrease in the rate of the asexual growth, suggesting that the
enzyme, although lost later in infection, may be important in the earlier
development of the parasite. By contrast, the lack of PKC had no effect on
the production of sexual stage parasites.
Volume 89,
Issue 5,
pp. 1770-1778,
03/01/1997
Copyright © 1997 by The American Society of Hematology
