Dissecting the gene expression, subcellular localization and function of small variant surface antigens
In addition to PfEMP1, which certainly mediates antigenic variation and endothelial receptor binding of P. falciparum, much less is known about the small variant surface antigens families RIFIN, STEVOR and PfMC-2TM. Interestingly, they members have been localized at different subcellular sites within the infected red blood cell and are, therefore, candidates for mediating several of the patho-physiological events during malaria disease. However, a better understanding of these small variant surface protein families is necessary and may reveal new targets for intervention. To get more insight in their function, we established analytical tools for analyzing parasites obtained from malaria patients, whose gene expression and protein localization is not influenced by prolonged in vitro-cultivation. We could already show that the gene expression of RIFIN- and STEVOR-encoding genes is enhanced in vivo and that proteins of both families contribute to the surface coat of the infected red blood cell. Currently, we are characterizing the gene expression, localization and functional role of small variant surface antigen in the invasive stage, the merozoite, as well as in other life cycle stages of the parasite.