Plasmodium spp. and Toxoplasma gondii are important members of the apicomplexan phylum, collectively they pose a considerable threat to human health and result in worldwide economic losses. Apicomplexan parasites have evolved an array of specialised organelles which they exploit to enable their parasitic lifestyle. The apical micronemes are critical for motility, invasion and egress. In this thesis, we identify and investigate multiple proteins contributing to microneme secretion, acting at the level of signalling for exocytosis or towards the apical replenishment of micronemes. Apicomplexan integral membrane proteins of the Major Facilitator Superfamily (MFS) have been found to be critically involved in nutrient uptake, organelle biogenesis and maturation. In light of these results, we have performed a restricted screen of MFSs in T. gondii. Combining both conditional genetic depletion with untargeted metabolomic analysis we investigate the proteins role and the nature of the metabolites transported.