Investigating the interaction between the malaria circumsporozoite protein and host importin-α proteins

Malaria is one of the ‘Big Four’ deadliest human-infectious disease and is transmitted by the female

Anopheles mosquito. This disease is caused by parasites from the Plasmodium genus. The lifecycle starts

with the presence of sporozoites (SPZs) in the bloodstream of the human host as a result of a bite from

an infected mosquito. These SPZs can then reach and enter the liver cells through the interaction

between one of their major surface proteins, the circumsporozoite protein (CSP), and the highly sulfated

heparan sulfate proteoglycans on the liver cells. It is speculated that, once inside the liver cell, CSP can

enter the cytoplasm and possibly prevent the transport of some transcription factors to the nucleus of the

liver cell. This may result in the dampening of the inflammatory responses and thus promote the survival

of the parasite. Once the parasite reaches the blood phase, symptoms such as the characteristic fever

attacks can occur. It is important that malaria is treated properly and on time to prevent further

complications. Chloroquine- and artemisin-based therapies can be used as treatment. However, the

increasing resistance against these treatments is a motive to find new ways to combat or treat malaria.

The aim of this thesis was to investigate whether there is an interaction between the importin-α proteins

and the CSP of both P. falciparum and P. berghei. To achieve this, PfaCSPFL and PbeCSPFL were

recombinantly produced using E. coli cells and purified using chromatographic techniques. To obtain

both human and murine importin-α proteins, respectively HepG2 and Hepa1-6 cells were cultivated.

Finally, pull-down assays were performed to investigate whether there is a possible interaction between

CSP and importin-α proteins.