The endoplasmic reticulum membrane protein complex localizes to the mitochondrial - endoplasmic reticulum interface and its subunits modulate phospholipid biosynthesis in Trypanosoma brucei

The endoplasmic reticulum membrane complex (EMC) is a versatile complex that plays a key role in membrane protein biogenesis in the ER. Deletion of the complex has wide-ranging consequences including ER stress, disturbance in lipid transport and organelle tethering, among others. Here we report the...

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Bibliographic Details
Published in:PLoS pathogens 2022-05, Vol.18 (5), p.e1009717-e1009717
Main Authors: Iyer, Advaitha, Niemann, Moritz, Serricchio, Mauro, Dewar, Caroline E, Oeljeklaus, Silke, Farine, Luce, Warscheid, Bettina, Schneider, André, Bütikofer, Peter
Format: Article
Language:English
Subjects:
Biology and Life Sciences
Biosynthesis
Cell culture
Cell cycle
Cellular control mechanisms
CRISPR
Depletion
Endoplasmic reticulum
Eukaryotes
Genetic aspects
Immunoprecipitation
Lecithin
Lipids
Localization
Mammals
Mass spectrometry
Mass spectroscopy
Membrane proteins
Membranes
Mitochondria
Parasites
Phosphatidylcholine
Phosphatidylethanolamine
Phospholipids
Properties
Proteins
Proteomics
Research and Analysis Methods
Tethering
Trypanosoma brucei
Virulence (Microbiology)
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Summary:The endoplasmic reticulum membrane complex (EMC) is a versatile complex that plays a key role in membrane protein biogenesis in the ER. Deletion of the complex has wide-ranging consequences including ER stress, disturbance in lipid transport and organelle tethering, among others. Here we report the function and organization of the evolutionarily conserved EMC (TbEMC) in the highly diverged eukaryote, Trypanosoma brucei. Using (co-) immunoprecipitation experiments in combination with mass spectrometry and whole cell proteomic analyses of parasites after depletion of select TbEMC subunits, we demonstrate that the TbEMC is composed of 9 subunits that are present in a high molecular mass complex localizing to the mitochondrial-endoplasmic reticulum interface. Knocking out or knocking down of single TbEMC subunits led to growth defects of T. brucei procyclic forms in culture. Interestingly, we found that depletion of individual TbEMC subunits lead to disruption of de novo synthesis of phosphatidylcholine (PC) or phosphatidylethanolamine (PE), the two most abundant phospholipid classes in T. brucei. Downregulation of TbEMC1 or TbEMC3 inhibited formation of PC while depletion of TbEMC8 inhibited PE synthesis, pointing to a role of the TbEMC in phospholipid synthesis. In addition, we found that in TbEMC7 knock-out parasites, TbEMC3 is released from the complex, implying that TbEMC7 is essential for the formation or the maintenance of the TbEMC.
ISSN:1553-7374
1553-7366
1553-7374
DOI:10.1371/journal.ppat.1009717