gms | German Medical Science

Plasmodium falciparum, the agent responsible for malaria tropica, belongs to the taxon of the Alveolata, which possess a common morphological feature known as the inner membrane complex (IMC). The IMC is located below the plasma membrane of the protist and plays an important role in conferring shape and stability to the cell. In Apicomplexan parasites, the IMC is also important for motility and host cell invasion. The IMC is among others present in gametocytes, plasmodial sexual precursor cells, which transform into gametes, once they are taken up by the blood-feeding mosquito, and which therefore play an important role in transmission of malaria. Till date neither the function of the gametocyte IMC nor its fate, when it is degraded during gametogenesis, is well known. In this study we aim to identify the components of the IMC of P. falciparum gametocytes with focus on the alveolin family (e.g. Alv2, Alv5, Alv6, IMC1a, IMC1b, IMC1h, PF3D7_0823500, and PF3D7_0525800) as well as the multi-transmembrane proteins (e.g. GAPM1, GAPM2, GAPM3 and PF3D7_0522600). Firstly, transcript levels of the respective IMC genes were determined in the asexual blood stages as well as in immature, mature and activated gametocytes using semi-quantitative RT PCR. Increased transcript expression was detected for alv2, alv5, alv7, imc1b and imc1h during gametocyte maturation and gametogenesis. The expression and localization of these candidate proteins were further determined by Western blotting and indirect immunofluorescence assays using polyclonal antisera directed against the IMC components. Preliminary results indicate localization of Alv2 in close proximity to known components of the IMC e.g. GAP45. Moreover, functional characterization of Alv2 is planned via reverse genetic studies.