Stage-dependent expression and vacuolar localization of Plasmodium berghei chloroquine resistance transporter (CRT).

Plasmodium parasites encode a chloroquine resistance transporter (CRT), which is an integral membrane protein of the digestive vacuole and transports the antimalarial compound chloroquine out of this organelle. Here, we profiled the spatio-temporal expression of CRT during life cycle progression employing CRT-mCherry Plasmodium berghei parasites. We show that CRT is expressed during asexual blood stage growth and localizes to the hemozoin-containing digestive vacuole. The compartmentalized CRT-mCherry signal is also abundant in gametocytes and ookinetes, indicating that CRT continues to exert important functions in this digestive organelle up until mosquito midgut colonization. Expression is switched off during sporogony and early liver infection but CRT-mCherry is present again in mature liver stages, likely in preparation for blood infection. Together, visualization of the P. berghei digestive vacuole by endogenous tagging of PbCRT revealed expression of this transport protein and the presence of this cellular compartment beyond asexual propagation inside erythrocytes.