Mutant/mutation
The mutant expresses a C-terminal GFP-tagged version of VIT

Protein (function)
Appropriate storage of any excess of iron, which is not used metabolically, is essential to prevent cellular toxicity due to engagement of iron in Fenton-type chemistry in the presence of oxygen and production of potentially damaging reactive oxygen species. Ferritin represents the most common and ancient mechanism of iron storage and homeostasis in nature, as it is found in most bacteria, archaea, plants and animals, but not in yeast. In the absence of ferritin, the yeast vacuole serves as the main iron-storage/sequestration organelle. In response to demands, iron moves to and from the yeast vacuole through the activity of iron transporters in the yeast vacuolar membrane; CCC1 (Ca2+-sensitive cross complementer 1) is proposed to import iron, while a complex constituted by Smf3p and Fet5p-Fth1p exports iron. Thus, vacuolar sequestration by CCC1 in yeast is likely to be the primary mechanism for detoxification of excess iron in this organism. In addition to ferritin found in plastids, plants also have several homologues of CCC1, named vacuolar iron transporters (VITs), which are likely to transport not only iron but also other divalent cations such as manganese and zinc into the vacuole for storage and detoxification.
Plasmodium parasites do not contain a homologue of ferritin or any other known iron-storage protein. However, Plasmodium spp. genomes contain one orthologue of plant VIT and yeast CCC1 proteins.

Phenotype
Analysis of a mutant lacking expression of VIT (RMgm-1411) showed reduced growth/multiplication of asexual blood stages and reduced liver stage development.

Analyses of the mutant expressing the GFP-tagged version of VIT showed VIT-GFP expression in blood stages, (mature) oocysts and (mature) liver stages.

Additional information
Evidence is presented that VIT plays a role in iron transport, suggesting that it plays a role in iron detoxification.

Confocal analysis after immunostaining with anti-GFP antibodies showed PbVIT expression in asexual blood stages, mosquito and liver stages of infection. In blood-stage parasites, the tagged version of PbVIT mainly co-localized with PbBiP to the parasite’s endoplasmic reticulum. No PbVIT-GFP signal was observed in regions around hemozoin crystals in blood-stage parasites. In oocysts and liver-stage parasites PbVIT-GFP also co-localized with PbBiP. Combined, these data  support the idea that PbVIT is expressed mainly in the parasite ER throughout the parasite’s life cycle.

Other mutants
A mutant lacking expression of VIT (RMgm-1411)