Translational repression controls temporal expression of the Plasmodium berghei LCCL protein complex

Plasmodium LCCL proteins comprise a family of six proteins that function as a protein complex and have essential roles in sporozoite transmission. In Plasmodium berghei, family members PbLAP1, PbLAP2 and PbLAP3 have been shown to be expressed in gametocytes and, following gametogenesis and fertilization, to be targeted to distinctive multivesicular organelles termed crystalloids that form in the ookinete. Here, we show by GFP-tagging that PbLAP4, PbLAP5 and PbLAP6, like their family members, are associated with the crystalloids. However, in contrast to their family members, protein expression of PbLAP4, PbLAP5 and PbLAP6 was not detected in gametocytes, even though transcription of the corresponding genes is most prominent in the sexual blood stage parasites. These results suggest that translational repression controls expression of the LCCL protein repertoire and, consequently, the temporal function of the protein complex during P. berghei development in the mosquito.