Volker Heussler Profile
	Research Focus:

My group at the Bernhard Nocht Institute (BNI) in Hamburg concentrates on the biology of the Plasmodium berghei liver stage. We analyse the late phases of hepatocyte infection and are interested in parasite-dependent host cell signalling and parasite-mediated effects on the host cell survival. In particular, we study the molecular and cell biological aspects of the transition from the liver stage to the blood stage of the parasite.

During liver stage schizogony, the parasite blocks the apoptotic machinery of its host cell. However, upon merozoite formation, a parasite-mediated host cell death is induced, which clearly differs from apoptosis. Remarkably, merozoite-filled vesicles, called merosomes, bud off the infected hepatocytes. Intravital microscopy revealed that merosomes reach the blood vessels of the liver before merozoites are released to infect red blood cells. Although some important molecular details of this event are known, it is still not clear how merosomes reach the blood stream and how the dying cell is stabilised.

The main goals are now to investigate the function of the host cell cytoskeleton during merosome formation, to characterise the role of parasite proteases and protease inhibitors during host cell death and to define the molecular mechanism of the parasite-mediated inhibition of host cell apoptosis during schizogony. Other topics of interest are the identification and characterisation of liver stage-specific secreted P. berghei proteins and the promotor region of the corresponding genes. We have already identified a gene that is strongly expressed only in late liver stages and have generated knockout parasite strains to characterise the function of the protein and to evaluate the knockout parasite as a possible attenuated vaccine strain. Together with the group of Tim Gilberger at the BNI, we will study the vesicle transport in liver stage parasites and in infected host cells.

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