RT Journal Article SR Electronic T1 PMRT1, a Plasmodium specific parasite plasma membrane transporter is essential for asexual and sexual blood stage development JF bioRxiv FD Cold Spring Harbor Laboratory SP 2021.12.21.473770 DO 10.1101/2021.12.21.473770 A1 Jan Stephan Wichers A1 Paolo Mesén-Ramírez A1 Gwendolin Fuchs A1 Jing Yu-Strzelczyk A1 Jan Stäcker A1 Heidrun von Thien A1 Arne Alder A1 Isabelle Henshall A1 Benjamin Liffner A1 Georg Nagel A1 Christian Löw A1 Danny Wilson A1 Tobias Spielmann A1 Shiqiang Gao A1 Tim-Wolf Gilberger A1 Anna Bachmann A1 Jan Strauss YR 2022 UL http://biorxiv.org/content/early/2022/03/12/2021.12.21.473770.abstract AB Membrane transport proteins perform crucial roles in cell physiology. The obligate intracellular parasite Plasmodium falciparum, an agent of human malaria, relies on membrane transport proteins for the uptake of nutrients from the host, disposal of metabolic waste, exchange of metabolites between organelles and generation and maintenance of transmembrane electrochemical gradients for its growth and replication within human erythrocytes. Despite their importance for Plasmodium cellular physiology, the functional roles of a number of membrane transport proteins remain unclear, which is particularly true for orphan membrane transporters that have no or limited sequence homology to transporter proteins in other evolutionary lineages. Therefore, in the current study, we applied endogenous tagging, targeted gene disruption, conditional knockdown and knockout approaches to investigate the subcellular localization and essentiality of six membrane transporters during intraerythrocytic development of P. falciparum parasites. They are localized at different subcellular structures – the food vacuole, the apicoplast, and the parasite plasma membrane – and four out of the six membrane transporters are essential during asexual development. Additionally, the plasma membrane resident transporter 1 (PMRT1, PF3D7_1135300), a unique Plasmodium-specific plasma membrane transporter, was shown to be essential for gametocytogenesis and functionally conserved within the genus Plasmodium. Overall, we reveal the importance of four orphan transporters to blood stage P. falciparum development, which have diverse intracellular localizations and putative functions.Importance Plasmodium falciparum-infected erythrocytes possess multiple compartments with designated membranes. Transporter proteins embedded in these membranes do not only facilitate movement of nutrients, metabolites and other molecules between these compartments, but are common therapeutic targets and can also confer antimalarial drug resistance. Orphan membrane transporter in P. falciparum without sequence homology to transporters in other evolutionary lineages and divergent to host transporters may constitute attractive targets for novel intervention approaches. Here, we localized six of these putative transporters at different subcellular compartments and probed into their importance during asexual parasite growth using reverse genetic approaches. In total, only two candidates turned out to be dispensable for the parasite, highlighting four candidates as putative targets for therapeutic interventions. This study reveals the importance of several orphan transporters to blood stage P. falciparum development.Competing Interest StatementThe authors have declared no competing interest.