Signaling during the invasion of host cells by Toxoplasma gondii

Invasion of host cells is essential for the pathogenicity of Toxoplasma gon dii. This review examines the signal transduction pathways that lead to the internalization of T. gondii. We demonstrate that extra- and intracellular Ca2+ mobilization, Ca2+-calmodulin complex and phospholipase A(2) activiti es are required for T. gondii entry. T. gondii also causes the activation o f mitogen-activated protein kinase in infected cells and modifies its ionic environment during its intracellular state. Thus, many of the signaling sy stems found in other eukaryotes are operative in Toxoplasma invasion. (C) 1 999 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.