An Interactome-Centered Protein Discovery Approach Reveals Novel Components Involved in Mitosome Function and Homeostasis in Giardia lamblia.

Rout, Samuel; Zumthor, Jon Paulin; Schraner, Elisabeth M; Faso, Carmen; Hehl, Adrian B (2016). An Interactome-Centered Protein Discovery Approach Reveals Novel Components Involved in Mitosome Function and Homeostasis in Giardia lamblia. PLoS pathogens, 12(12), e1006036. Public Library of Science 10.1371/journal.ppat.1006036

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Protozoan parasites of the genus Giardia are highly prevalent globally, and infect a wide range of vertebrate hosts including humans, with proliferation and pathology restricted to the small intestine. This narrow ecological specialization entailed extensive structural and functional adaptations during host-parasite co-evolution. An example is the streamlined mitosomal proteome with iron-sulphur protein maturation as the only biochemical pathway clearly associated with this organelle. Here, we applied techniques in microscopy and protein biochemistry to investigate the mitosomal membrane proteome in association to mitosome homeostasis. Live cell imaging revealed a highly immobilized array of 30-40 physically distinct mitosome organelles in trophozoites. We provide direct evidence for the single giardial dynamin-related protein as a contributor to mitosomal morphogenesis and homeostasis. To overcome inherent limitations that have hitherto severely hampered the characterization of these unique organelles we applied a novel interaction-based proteome discovery strategy using forward and reverse protein co-immunoprecipitation. This allowed generation of organelle proteome data strictly in a protein-protein interaction context. We built an initial Tom40-centered outer membrane interactome by co-immunoprecipitation experiments, identifying small GTPases, factors with dual mitosome and endoplasmic reticulum (ER) distribution, as well as novel matrix proteins. Through iterative expansion of this protein-protein interaction network, we were able to i) significantly extend this interaction-based mitosomal proteome to include other membrane-associated proteins with possible roles in mitosome morphogenesis and connection to other subcellular compartments, and ii) identify novel matrix proteins which may shed light on mitosome-associated metabolic functions other than Fe-S cluster biogenesis. Functional analysis also revealed conceptual conservation of protein translocation despite the massive divergence and reduction of protein import machinery in Giardia mitosomes.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Biology > Institute of Cell Biology
08 Faculty of Science > Department of Biology > Institute of Cell Biology > Parasitologie

UniBE Contributor:

Faso, Carmen

Subjects:

500 Science > 570 Life sciences; biology
500 Science > 590 Animals (Zoology)

ISSN:

1553-7366

Publisher:

Public Library of Science

Language:

English

Submitter:

Carmen Faso

Date Deposited:

19 Sep 2019 15:55

Last Modified:

27 Oct 2019 19:15

Publisher DOI:

10.1371/journal.ppat.1006036

PubMed ID:

27926928

BORIS DOI:

10.7892/boris.131611

URI:

https://boris.unibe.ch/id/eprint/131611

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