IMC10 and LMF1 mediate membrane contact between the mitochondrion and the inner membrane complex in Toxoplasma gondii [article]

Rodolpho Ornitz Oliveira Souza, Gustavo Arrizabalaga, Kylie N Jacobs
2022 bioRxiv   pre-print
The single mitochondrion of Toxoplasma gondii is highly dynamic, being predominantly in a peripherally distributed lasso-shape in intracellular parasites and collapsed in extracellular ones. The peripheral positioning of the mitochondrion is associated with apparent contacts between the mitochondrion membrane and the parasite pellicle. The outer mitochondrial membrane-associated protein LMF1 is critical for the correct positioning of the mitochondrion, and in its absence, intracellular
more » ... fail to form the lasso-shaped mitochondrion. To identify other proteins that participate in tethering the parasite's mitochondrion to the pellicle, we performed a yeast two-hybrid screen for LMF1 interactors. We identified 70 putative interactors, six of which are known to localize to the apical end of the parasite, two to the mitochondrial membrane, and three localize to the inner membrane complex (IMC), a component of the parasite pellicle. Using reciprocal immunoprecipitation and proximity ligation assays, we confirmed the interaction of LMF1 with the pellicle protein IMC10, with a hypothetical protein known to be part of the conoid, and with an ATPase-Guanylyl Cyclase. Conditional knockdown of IMC10 does not affect parasite viability but severely affects mitochondrial morphology in intracellular parasites and mitochondrial distribution to the daughter cells during division. In effect, IMC10 knockdown phenocopies disruption of LMF1, suggesting that these two proteins define a novel membrane tether between Toxoplasma's mitochondrion and the inner membrane complex.
doi:10.1101/2022.04.01.486766 fatcat:oo2ewm2f6jcepbd4zxyddfo4iu