Independent evolution of functionally exchangeable mitochondrial outer membrane import complexes

Vitali, Daniela G.; Käser, Sandro; Kolb, Antonia; Dimmer, Kai Stefan; Schneider, André; Rapaport, Doron

doi:10.7554/elife.34488

Cited by 36 publications

(33 citation statements)

References 40 publications

(84 reference statements)

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“…However, if so, Atg43 may not necessarily be involved in all of the import events mediated by the MIM complex, as the mitochondrial loading of Tom70 is highly dependent on the MIM complex but not on Atg43. Alternatively, similar to pATOM36 of trypanosomes, a functional analog of the MIM complex, Atg43 and the MIM complex may contribute to mitochondrial DNA segregation ( Vitali et al, 2018 ). Notably, the C-terminal component of Atg43, which is required for the interaction with the MIM complex and normal cell growth, is shared among fungi.…”

Section: Discussionmentioning

confidence: 99%

Atg43 tethers isolation membranes to mitochondria to promote starvation-induced mitophagy in fission yeast

Fukuda

Ebi

Saigusa

et al. 2020

eLife

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Degradation of mitochondria through mitophagy contributes to the maintenance of mitochondrial function. In this study, we identified that Atg43, a mitochondrial outer membrane protein, serves as a mitophagy receptor in the model organism Schizosaccharomyces pombe to promote the selective degradation of mitochondria. Atg43 contains an Atg8-family-interacting motif essential for mitophagy. Forced recruitment of Atg8 to mitochondria restores mitophagy in Atg43-deficient cells, suggesting that Atg43 tethers expanding isolation membranes to mitochondria. We found that the mitochondrial import factors, including the Mim1–Mim2 complex and Tom70, are crucial for mitophagy. Artificial mitochondrial loading of Atg43 bypasses the requirement of the import factors, suggesting that they contribute to mitophagy through Atg43. Atg43 not only maintains growth ability during starvation but also facilitates vegetative growth through its mitophagy-independent function. Thus, Atg43 is a useful model to study the mechanism and physiological roles, as well as the origin and evolution, of mitophagy in eukaryotes.

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Section: Discussionmentioning

confidence: 99%

Atg43 tethers isolation membranes to mitochondria to promote starvation-induced mitophagy in fission yeast

Fukuda

Ebi

Saigusa

et al. 2020

eLife

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“…We previously found that the Trypanosoma brucei protein pATOM36 can functionally compensate the absence of the MIM complex (Vitali et al, 2018). Hence, we next aimed to test whether this protein can also replace the MIM function in facilitating the membrane integration of the two new substrates that we identified, Atg32 and Gem1.…”

Section: The Mim Complex Contributes To the Membrane Integration Of Tmentioning

confidence: 99%

The Biogenesis of Mitochondrial Outer Membrane Proteins Show Variable Dependence on Import Factors

et al. 2020

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Biogenesis of mitochondrial outer membrane proteins involves their integration into the lipid bilayer. Among these proteins are those that form a single-span topology, but our understanding of their biogenesis is scarce. In this study, we found that the MIM complex is required for the membrane insertion of some single-span proteins. However, other such proteins integrate into the membrane in a MIM-independent manner. Moreover, the biogenesis of the studied proteins was dependent to a variable degree on the TOM receptors Tom20 and Tom70. We found that Atg32 C-terminal domain mediates dependency on Tom20, whereas the cytosolic domains of Atg32 and Gem1 facilitate MIM involvement. Collectively, our findings (1) enlarge the repertoire of MIM substrates to include also tail-anchored proteins, (2) provide new mechanistic insights to the functions of the MIM complex and TOM import receptors, and (3) demonstrate that the biogenesis of MOM single-span proteins shows variable dependence on import factors.

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“…Remarkably, pATOM36 is not only essential for TAC function, but also for the biogenesis of a subset of mitochondrial OM proteins (Käser et al, 2016). In fact, experiments in yeast and T. brucei have revealed that pATOM36 is a functional analog of the yeast mitochondrial inner-membrane import machinery (MIM) complex, which consists of Mim1 and Mim2 (Vitali et al, 2018). In line with its dual function, pATOM36 localizes to the DM subdomain of the TAC, as well as all over the OM (Käser et al, 2016).…”

Section: Tac Subunits -Dmmentioning

confidence: 99%

Failure is not an option – mitochondrial genome segregation in trypanosomes

Schneider

Ochsenreiter

2018

Journal of Cell Science

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Unlike most other model eukaryotes, and its relatives have a single mitochondrion with a single-unit mitochondrial genome that is termed kinetoplast DNA (kDNA). Replication of the kDNA is coordinated with the cell cycle. During binary mitochondrial fission and prior to cytokinesis, the replicated kDNA has to be faithfully segregated to the daughter organelles. This process depends on the tripartite attachment complex (TAC) that physically links the kDNA across the two mitochondrial membranes with the basal body of the flagellum. Thus, the TAC couples segregation of the replicated kDNA with segregation of the basal bodies of the old and the new flagellum. In this Review, we provide an overview of the role of the TAC in kDNA inheritance in We focus on recent advances regarding the molecular composition of the TAC, and discuss how the TAC is assembled and how its subunits are targeted to their respective TAC subdomains. Finally, we will contrast the segregation of the single-unit kDNA in trypanosomes to mitochondrial genome inheritance in yeast and mammals, both of which have numerous mitochondria that each contain multiple genomes.

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Independent evolution of functionally exchangeable mitochondrial outer membrane import complexes

Cited by 36 publications

References 40 publications

Atg43 tethers isolation membranes to mitochondria to promote starvation-induced mitophagy in fission yeast

Atg43 tethers isolation membranes to mitochondria to promote starvation-induced mitophagy in fission yeast

The Biogenesis of Mitochondrial Outer Membrane Proteins Show Variable Dependence on Import Factors

Failure is not an option – mitochondrial genome segregation in trypanosomes

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