scholarly journals Structure of the mitochondrial inner membrane AAA+ protease YME1 gives insight into substrate processing

Science ◽  
2017 ◽  
Vol 358 (6363) ◽  
pp. eaao0464 ◽  
Author(s):  
Cristina Puchades ◽  
Anthony J. Rampello ◽  
Mia Shin ◽  
Christopher J. Giuliano ◽  
R. Luke Wiseman ◽  
...  
Keyword(s):  
Inner Membrane ◽  
Mitochondrial Inner Membrane ◽  
Substrate Processing ◽  
Insight Into

scholarly journals MINOS1 is a conserved component of mitofilin complexes and required for mitochondrial function and cristae organization

2012 ◽  
Vol 23 (2) ◽  
pp. 247-257 ◽  
Author(s):  
Alwaleed K. Alkhaja ◽  
Daniel C. Jans ◽  
Miroslav Nikolov ◽  
Milena Vukotic ◽  
Oleksandr Lytovchenko ◽  
...  
Keyword(s):  
Carbon Sources ◽  
Ultrastructural Level ◽  
Yeast Cells ◽  
Mitochondrial Morphology ◽  
Inner Membrane ◽  
Mitochondrial Inner Membrane ◽  
Inner Membrane Protein ◽  
Protein Rich ◽  
Boundary Membrane ◽  
Insight Into

The inner membrane of mitochondria is especially protein rich and displays a unique morphology characterized by large invaginations, the mitochondrial cristae, and the inner boundary membrane, which is in proximity to the outer membrane. Mitochondrial inner membrane proteins appear to be not evenly distributed in the inner membrane, but instead organize into functionally distinct subcompartments. It is unknown how the organization of the inner membrane is achieved. We identified MINOS1/MIO10 (C1orf151/YCL057C-A), a conserved mitochondrial inner membrane protein. mio10-mutant yeast cells are affected in growth on nonfermentable carbon sources and exhibit altered mitochondrial morphology. At the ultrastructural level, mutant mitochondria display loss of inner membrane organization. Proteomic analyses reveal MINOS1/Mio10 as a novel constituent of Mitofilin/Fcj1 complexes in human and yeast mitochondria. Thus our analyses reveal new insight into the composition of the mitochondrial inner membrane organizing machinery.

scholarly journals Atomic structure of the mitochondrial inner membrane AAA+ protease YME1 reveals the mechanism of substrate processing

2017 ◽  
Author(s):  
Cristina Puchades ◽  
Anthony J. Rampello ◽  
Mia Shin ◽  
Christopher J. Giuliano ◽  
R. Luke Wiseman ◽  
...  
Keyword(s):  
Large Scale ◽  
Atp Hydrolysis ◽  
Inner Mitochondrial Membrane ◽  
Inner Membrane ◽  
Conserved Residues ◽  
Mitochondrial Inner Membrane ◽  
Translocation Mechanism ◽  
Substrate Processing ◽  
Aaa Atpases ◽  
Proteolytic Chamber

AbstractWe present the first atomic model of a substrate-bound inner mitochondrial membrane AAA+ quality control protease, YME1. Our ~3.4 Å cryo-EM structure reveals how the ATPases form a closed spiral staircase encircling an unfolded substrate, directing it toward the flat, symmetric protease ring. Importantly, the structure reveals how three coexisting nucleotide states allosterically induce distinct positioning of tyrosines in the central channel, resulting in substrate engagement and translocation to the negatively charged proteolytic chamber. This tight coordination by a network of conserved residues defines a sequential, around-the-ring ATP hydrolysis cycle that results in step-wise substrate translocation. Furthermore, we identify a hinge-like linker that accommodates the large-scale nucleotide-driven motions of the ATPase spiral independently of the contiguous planar proteolytic base. These results define the first molecular mechanism for a mitochondrial inner membrane AAA+ protease and reveal a translocation mechanism likely conserved for other AAA+ ATPases.

scholarly journals MINSTED fluorescence localization and nanoscopy

2021 ◽  
Author(s):  
Michael Weber ◽  
Marcel Leutenegger ◽  
Stefan Stoldt ◽  
Stefan Jakobs ◽  
Tiberiu S. Mihaila ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Super Resolution ◽  
Diffraction Limit ◽  
Stimulated Emission ◽  
Far Field ◽  
Inner Membrane ◽  
Mitochondrial Inner Membrane ◽  
Molecular Scale ◽  
Localization Precision ◽  
Super Resolution Microscopy

AbstractWe introduce MINSTED, a fluorophore localization and super-resolution microscopy concept based on stimulated emission depletion (STED) that provides spatial precision and resolution down to the molecular scale. In MINSTED, the intensity minimum of the STED doughnut, and hence the point of minimal STED, serves as a movable reference coordinate for fluorophore localization. As the STED rate, the background and the required number of fluorescence detections are low compared with most other STED microscopy and localization methods, MINSTED entails substantially less fluorophore bleaching. In our implementation, 200–1,000 detections per fluorophore provide a localization precision of 1–3 nm in standard deviation, which in conjunction with independent single fluorophore switching translates to a ~100-fold improvement in far-field microscopy resolution over the diffraction limit. The performance of MINSTED nanoscopy is demonstrated by imaging the distribution of Mic60 proteins in the mitochondrial inner membrane of human cells.

scholarly journals Characterization of Mmp37p, aSaccharomyces cerevisiaeMitochondrial Matrix Protein with a Role in Mitochondrial Protein Import

2006 ◽  
Vol 17 (9) ◽  
pp. 4051-4062 ◽  
Author(s):  
Michelle R. Gallas ◽  
Mary K. Dienhart ◽  
Rosemary A. Stuart ◽  
Roy M. Long
Keyword(s):  
Matrix Protein ◽  
Protein Import ◽  
Mitochondrial Protein ◽  
Temperature Sensitive ◽  
Inner Membrane ◽  
Mitochondrial Inner Membrane ◽  
Close Proximity ◽  
The Matrix ◽  
Targeting Signal

Many mitochondrial proteins are encoded by nuclear genes and after translation in the cytoplasm are imported via translocases in the outer and inner membranes, the TOM and TIM complexes, respectively. Here, we report the characterization of the mitochondrial protein, Mmp37p (YGR046w) and demonstrate its involvement in the process of protein import into mitochondria. Haploid cells deleted of MMP37 are viable but display a temperature-sensitive growth phenotype and are inviable in the absence of mitochondrial DNA. Mmp37p is located in the mitochondrial matrix where it is peripherally associated with the inner membrane. We show that Mmp37p has a role in the translocation of proteins across the mitochondrial inner membrane via the TIM23-PAM complex and further demonstrate that substrates containing a tightly folded domain in close proximity to their mitochondrial targeting sequences display a particular dependency on Mmp37p for mitochondrial import. Prior unfolding of the preprotein, or extension of the region between the targeting signal and the tightly folded domain, relieves their dependency for Mmp37p. Furthermore, evidence is presented to show that Mmp37 may affect the assembly state of the TIM23 complex. On the basis of these findings, we hypothesize that the presence of Mmp37p enhances the early stages of the TIM23 matrix import pathway to ensure engagement of incoming preproteins with the mtHsp70p/PAM complex, a step that is necessary to drive the unfolding and complete translocation of the preprotein into the matrix.

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