scholarly journals In vivo study in Trypanosoma brucei links mitochondrial transfer RNA import to mitochondrial protein import

EMBO Reports ◽  
2011 ◽  
Vol 12 (8) ◽  
pp. 825-832 ◽  
Author(s):  
Florence Tschopp ◽  
Fabien Charrière ◽  
André Schneider
Keyword(s):  
Trypanosoma Brucei ◽  
Protein Import ◽  
Mitochondrial Protein ◽  
Transfer Rna ◽  
In Vivo Study ◽  
Mitochondrial Protein Import ◽  
Mitochondrial Transfer ◽  
Rna Import

Dynamic organization of the mitochondrial protein import machinery

2016 ◽  
Vol 397 (11) ◽  
pp. 1097-1114 ◽  
Author(s):  
Sebastian P. Straub ◽  
Sebastian B. Stiller ◽  
Nils Wiedemann ◽  
Nikolaus Pfanner
Keyword(s):  
Mitochondrial Membrane ◽  
Protein Import ◽  
Mitochondrial Protein ◽  
Membrane Dynamics ◽  
Intermembrane Space ◽  
Mitochondrial Protein Import ◽  
Precursor Proteins ◽  
Dynamic Cooperation

Abstract Mitochondria contain elaborate machineries for the import of precursor proteins from the cytosol. The translocase of the outer mitochondrial membrane (TOM) performs the initial import of precursor proteins and transfers the precursors to downstream translocases, including the presequence translocase and the carrier translocase of the inner membrane, the mitochondrial import and assembly machinery of the intermembrane space, and the sorting and assembly machinery of the outer membrane. Although the protein translocases can function as separate entities in vitro, recent studies revealed a close and dynamic cooperation of the protein import machineries to facilitate efficient transfer of precursor proteins in vivo. In addition, protein translocases were found to transiently interact with distinct machineries that function in the respiratory chain or in the maintenance of mitochondrial membrane architecture. Mitochondrial protein import is embedded in a regulatory network that ensures protein biogenesis, membrane dynamics, bioenergetic activity and quality control.

scholarly journals In Vivo Structure-Function Analysis and Redox Interactomes of Leishmania tarentolae Erv

2021 ◽  
Author(s):  
Gino L. Turra ◽  
Linda Liedgens ◽  
Frederik Sommer ◽  
Luzia Schneider ◽  
David Zimmer ◽  
...  
Keyword(s):  
Protein Import ◽  
Function Analysis ◽  
Mitochondrial Protein ◽  
Intermembrane Space ◽  
Mitochondrial Protein Import ◽  
Redox Biology ◽  
Oxidative Protein Folding ◽  
Mitochondrial Intermembrane Space ◽  
New Research

The discovery of the redox proteins Mia40/CHCHD4 and Erv1/ALR, as well as the elucidation of their relevance for oxidative protein folding in the mitochondrial intermembrane space of yeast and mammals, founded a new research topic in redox biology and mitochondrial protein import. The lack of Mia40/CHCHD4 in protist lineages raises fundamental and controversial questions regarding the conservation and evolution of this essential pathway.

scholarly journals Mitochondrial protein import is regulated by p17/PERMIT to mediate lipid metabolism and cellular stress

2019 ◽  
Vol 5 (9) ◽  
pp. eaax1978 ◽  
Author(s):  
Natalia Oleinik ◽  
Jisun Kim ◽  
Braden M. Roth ◽  
Shanmugam Panneer Selvam ◽  
Monika Gooz ◽  
...  
Keyword(s):  
Lipid Metabolism ◽  
Protein Import ◽  
Acute Stress ◽  
Cellular Stress ◽  
Mitochondrial Protein ◽  
Ceramide Synthase ◽  
Mitochondrial Protein Import ◽  
Genetic Ablation ◽  
Ceramide Generation

How lipid metabolism is regulated at the outer mitochondrial membrane (OMM) for transducing stress signaling remains largely unknown. We show here that this process is controlled by trafficking of ceramide synthase 1 (CerS1) from the endoplasmic reticulum (ER) to the OMM by a previously uncharacterized p17, which is now renamed protein that mediates ER-mitochondria trafficking (PERMIT). Data revealed that p17/PERMIT associates with newly translated CerS1 on the ER surface to mediate its trafficking to the OMM. Cellular stress induces Drp1 nitrosylation/activation, releasing p17/PERMIT to retrieve CerS1 for its OMM trafficking, resulting in mitochondrial ceramide generation, mitophagy and cell death. In vivo, CRISPR-Cas9–dependent genetic ablation of p17/PERMIT prevents acute stress-mediated CerS1 trafficking to OMM, attenuating mitophagy in p17/PERMIT−/− mice, compared to controls, in various metabolically active tissues, including brain, muscle, and pancreas. Thus, these data have implications in diseases associated with accumulation of damaged mitochondria such as cancer and/or neurodegeneration.

scholarly journals The Spliced Leader RNA Silencing (SLS) Pathway in Trypanosoma brucei Is Induced by Perturbations of Endoplasmic Reticulum, Golgi Complex, or Mitochondrial Protein Factors: Functional Analysis of SLS-Inducing Kinase PK3

mBio ◽  
2021 ◽  
Author(s):  
Uthman Okalang ◽  
Bar Mualem Bar-Ner ◽  
K. Shanmugha Rajan ◽  
Nehemya Friedman ◽  
Saurav Aryal ◽  
...  
Keyword(s):  
Functional Analysis ◽  
Trypanosoma Brucei ◽  
Golgi Complex ◽  
Rna Silencing ◽  
Protein Import ◽  
Mitochondrial Protein ◽  
Sulfhydryl Oxidase ◽  
Mitochondrial Protein Import ◽  
Spliced Leader ◽  
Quiescin Sulfhydryl Oxidase

In this study, we found that SLS is induced by depletion of the essential ER-resident chaperones BiP and calreticulin, ER oxidoreductin 1 (ERO1), and the Golgi complex-localized quiescin sulfhydryl oxidase (QSOX). Most strikingly, silencing of Rhomboid-like 1 (TIMRHOM1), involved in mitochondrial protein import, also induces SLS.

scholarly journals Determinism and contingencies shaped the evolution of mitochondrial protein import

2021 ◽  
Vol 118 (6) ◽  
pp. e2017774118
Author(s):  
Samuel Rout ◽  
Silke Oeljeklaus ◽  
Abhijith Makki ◽  
Jan Tachezy ◽  
Bettina Warscheid ◽  
...  
Keyword(s):  
Quantitative Proteomics ◽  
Protein Import ◽  
Hydrophobic Interactions ◽  
Mitochondrial Protein ◽  
Membrane Receptors ◽  
Mitochondrial Protein Import ◽  
Substrate Preferences ◽  
Import Receptors

Mitochondrial protein import requires outer membrane receptors that evolved independently in different lineages. Here we used quantitative proteomics and in vitro binding assays to investigate the substrate preferences of ATOM46 and ATOM69, the two mitochondrial import receptors of Trypanosoma brucei. The results show that ATOM46 prefers presequence-containing, hydrophilic proteins that lack transmembrane domains (TMDs), whereas ATOM69 prefers presequence-lacking, hydrophobic substrates that have TMDs. Thus, the ATOM46/yeast Tom20 and the ATOM69/yeast Tom70 pairs have similar substrate preferences. However, ATOM46 mainly uses electrostatic, and Tom20 hydrophobic, interactions for substrate binding. In vivo replacement of T. brucei ATOM46 by yeast Tom20 did not restore import. However, replacement of ATOM69 by the recently discovered Tom36 receptor of Trichomonas hydrogenosomes, while not allowing for growth, restored import of a large subset of trypanosomal proteins that lack TMDs. Thus, even though ATOM69 and Tom36 share the same domain structure and topology, they have different substrate preferences. The study establishes complementation experiments, combined with quantitative proteomics, as a highly versatile and sensitive method to compare in vivo preferences of protein import receptors. Moreover, it illustrates the role determinism and contingencies played in the evolution of mitochondrial protein import receptors.

scholarly journals Identification of Tam41 maintaining integrity of the TIM23 protein translocator complex in mitochondria

2006 ◽  
Vol 174 (5) ◽  
pp. 631-637 ◽  
Author(s):  
Yasushi Tamura ◽  
Yoshihiro Harada ◽  
Koji Yamano ◽  
Kazuaki Watanabe ◽  
Daigo Ishikawa ◽  
...  
Keyword(s):  
Protein Import ◽  
Mitochondrial Protein ◽  
Molecular Size ◽  
Yeast Cells ◽  
Temperature Sensitive ◽  
Inner Mitochondrial Membrane ◽  
Mitochondrial Protein Import ◽  
The Matrix

Newly synthesized mitochondrial proteins are imported into mitochondria with the aid of protein translocator complexes in the outer and inner mitochondrial membranes. We report the identification of yeast Tam41, a new member of mitochondrial protein translocator systems. Tam41 is a peripheral inner mitochondrial membrane protein facing the matrix. Disruption of the TAM41 gene led to temperature-sensitive growth of yeast cells and resulted in defects in protein import via the TIM23 translocator complex at elevated temperature both in vivo and in vitro. Although Tam41 is not a constituent of the TIM23 complex, depletion of Tam41 led to a decreased molecular size of the TIM23 complex and partial aggregation of Pam18 and -16. Import of Pam16 into mitochondria without Tam41 was retarded, and the imported Pam16 formed aggregates in vitro. These results suggest that Tam41 facilitates mitochondrial protein import by maintaining the functional integrity of the TIM23 protein translocator complex from the matrix side of the inner membrane.

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