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Ribeiro-Holbein, A.

Publications and source records attributed to Ribeiro-Holbein, A..

2 recordsLinked to original sources

A new class of lipid transfer proteins is required for the recycling of lipids from the P. falciparum digestive vacuole

Malaria parasites endocytose large quantities of hemoglobin from the host erythrocyte, a process critical for parasite survival, leading to extensive membrane internalization. While hemoglobin degradation in the digestive vacuole (DV) is well studied, how the parasite deals with the membranes arriving within the DV is unknown. Here we identified PfTUPA, a previously uncharacterized lipid transfer protein in the DV membrane that is needed for this function. PfTUPA contains a soluble TULIP-like lipid transport domain exposed to the DV lumen and a transmembrane lipid transfer domain of bacterial origin (PqiA) in the DV membrane. Structural comparisons revealed proteins with various PqiA and TULIP-like domain combinations across distant eukaryotic clades, indicating this is a frequent functional partnership. Hence, PfTUPA belongs to a new class of eukaryotic lipid transfer proteins that in malaria parasites is needed for a key function of its biology.

microbiology↗

A bridge-like lipid transfer protein is critical for generation of invasive stages in malaria parasites

Malaria blood stages build and maintain an intricate system of membranes during their cycle of rapid growth and schizogony (daughter-cell formation), requiring precise mechanisms of lipid synthesis and trafficking. Lipid transfer proteins (LTPs) at ER membrane contact sites (MCSs) have emerged as key for lipid distribution processes but remain largely unexplored in protozoans. Here we use the ER adaptor VAP to identify essential mechanisms of lipid transfer at ER-MCSs in P. falciparum. One PfVAP-interacting LTP was the bridge-like PfVPS13L1, which allows bulk flow of lipids between two apposed membranes. PfVPS13L1 bridges the ER with the nascent inner membrane complex (IMC), a de novo-generated organelle required for schizogony. Its loss-of-function reduced IMC growth and led to smaller anucleated progeny, impairing schizogony. Our data supports a model in which VPS13L1 is critical for the formation of apicomplexan invasive stages by mediating bulk transfer of lipids from the ER to the growing IMC.

cell biology↗