scholarly journals The inner membrane protein Mdm33 controls mitochondrial morphology in yeast

2003 ◽  
Vol 160 (4) ◽  
pp. 553-564 ◽  
Author(s):  
Marlies Messerschmitt ◽  
Stefan Jakobs ◽  
Frank Vogel ◽  
Stefan Fritz ◽  
Kai Stefan Dimmer ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Hollow Spheres ◽  
Ultrastructural Level ◽  
Mitochondrial Morphology ◽  
Membrane Structures ◽  
Matrix Space ◽  
Gene Encoding ◽  
Inner Membrane ◽  
Mitochondrial Inner Membrane ◽  
Inner Membrane Protein

Mitochondrial distribution and morphology depend on MDM33, a Saccharomyces cerevisiae gene encoding a novel protein of the mitochondrial inner membrane. Cells lacking Mdm33 contain ring-shaped, mostly interconnected mitochondria, which are able to form large hollow spheres. On the ultrastructural level, these aberrant organelles display extremely elongated stretches of outer and inner membranes enclosing a very narrow matrix space. Dilated parts of Δmdm33 mitochondria contain well-developed cristae. Overexpression of Mdm33 leads to growth arrest, aggregation of mitochondria, and generation of aberrant inner membrane structures, including septa, inner membrane fragments, and loss of inner membrane cristae. The MDM33 gene is required for the formation of net-like mitochondria in mutants lacking components of the outer membrane fission machinery, and mitochondrial fusion is required for the formation of extended ring-like mitochondria in cells lacking the MDM33 gene. The Mdm33 protein assembles into an oligomeric complex in the inner membrane where it performs homotypic protein–protein interactions. Our results indicate that Mdm33 plays a distinct role in the mitochondrial inner membrane to control mitochondrial morphology. We propose that Mdm33 is involved in fission of the mitochondrial inner membrane.

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 MAP-1 and IAP-1, Two Novel AAA Proteases with Catalytic Sites on Opposite Membrane Surfaces in Mitochondrial Inner Membrane ofNeurospora crassa

2001 ◽  
Vol 12 (9) ◽  
pp. 2858-2869 ◽  
Author(s):  
Carola Klanner ◽  
Holger Prokisch ◽  
Thomas Langer
Keyword(s):  
Matrix Space ◽  
Yeast Saccharomyces Cerevisiae ◽  
Inner Membrane ◽  
Functional Conservation ◽  
Membrane Surfaces ◽  
Mitochondrial Inner Membrane ◽  
Catalytic Sites ◽  
The Matrix ◽  
Inner Membrane Protein ◽  
Yeast Homolog

Eukaryotic AAA proteases form a conserved family of membrane-embedded ATP-dependent proteases but have been analyzed functionally only in the yeast Saccharomyces cerevisiae. Here, we have identified two novel members of this protein family in the filamentous fungus Neurospora crassa, which were termed MAP-1 and IAP-1. Both proteins are localized to the inner membrane of mitochondria. They are part of two similar-sized high molecular mass complexes, but expose their catalytic sites to opposite membrane surfaces, namely, the intermembrane and the matrix space. Disruption of iap-1 by repeat-induced point mutation caused a slow growth phenotype at high temperature and stabilization of a misfolded inner membrane protein against degradation. IAP-1 could partially substitute for functions of its yeast homolog Yme1, demonstrating functional conservation. However, respiratory growth at 37°C was not restored. Our results identify two components of the quality control system of the mitochondrial inner membrane in N. crassa and suggest that AAA proteases with catalytic sites exposed to opposite membrane surfaces are present in mitochondria of all eukaryotic cells.

Removal of a hydrophobic domain within the mature portion of a mitochondrial inner membrane protein causes its mislocalization to the matrix

1990 ◽  
Vol 10 (5) ◽  
pp. 1873-1881
Author(s):  
S M Glaser ◽  
B R Miller ◽  
M G Cumsky
Keyword(s):  
Amino Acids ◽  
Mitochondrial Matrix ◽  
Mature Protein ◽  
Wild Type ◽  
Inner Membrane ◽  
Hydrophobic Domain ◽  
Mitochondrial Inner Membrane ◽  
The Matrix ◽  
Inner Membrane Protein ◽  
Cognate Protein

We have examined the import and intramitochondrial localization of the precursor to yeast cytochrome c oxidase subunit Va, a protein of the mitochondrial inner membrane. The results of studies on the import of subunit Va derivatives carrying altered presequences suggest that the uptake of this protein is highly efficient. We found that a presequence of only 5 amino acids (Met-Leu-Ser-Leu-Arg) could direct the import and localization of subunit Va with wild-type efficiency, as judged by several different assays. We also found that subunit Va could be effectively targeted to the mitochondrial inner membrane with a heterologous presequence that failed to direct import of its cognate protein. The results presented here confirmed those of an earlier study and showed clearly that the information required to "sort" subunit Va to the inner membrane resides in the mature protein sequence, not within the presequence per se. We present additional evidence that the aforementioned sorting information is contained, at least in part, in a hydrophobic stretch of 22 amino acids residing within the C-terminal third of the protein. Removal of this domain caused subunit Va to be mislocalized to the mitochondrial matrix.

scholarly journals Mitochondrial Membrane Dynamics—Functional Positioning of OPA1

Antioxidants ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 186 ◽  
Author(s):  
Hakjoo Lee ◽  
Yisang Yoon
Keyword(s):  
Mitochondrial Membrane ◽  
Proteolytic Cleavage ◽  
Membrane Dynamics ◽  
Mitochondrial Morphology ◽  
Inner Membrane ◽  
Mitochondrial Inner Membrane ◽  
Functional Differences ◽  
New Information ◽  
New Development

The maintenance of mitochondrial energetics requires the proper regulation of mitochondrial morphology, and vice versa. Mitochondrial dynamins control mitochondrial morphology by mediating fission and fusion. One of them, optic atrophy 1 (OPA1), is the mitochondrial inner membrane remodeling protein. OPA1 has a dual role in maintaining mitochondrial morphology and energetics through mediating inner membrane fusion and maintaining the cristae structure. OPA1 is expressed in multiple variant forms through alternative splicing and post-translational proteolytic cleavage, but the functional differences between these variants have not been completely understood. Recent studies generated new information regarding the role of OPA1 cleavage. In this review, we will first provide a brief overview of mitochondrial membrane dynamics by describing fission and fusion that are mediated by mitochondrial dynamins. The second part describes OPA1-mediated fusion and energetic maintenance, the role of OPA1 cleavage, and a new development in OPA1 function, in which we will provide new insight for what OPA1 does and what proteolytic cleavage of OPA1 is for.

scholarly journals Mitochondrial inner membrane protein, Mic60/mitofilin in mammalian organ protection

2018 ◽  
Vol 234 (4) ◽  
pp. 3383-3393 ◽  
Author(s):  
Yansheng Feng ◽  
Ngonidzashe B. Madungwe ◽  
Jean C. Bopassa
Keyword(s):  
Membrane Protein ◽  
Organ Protection ◽  
Inner Membrane ◽  
Mitochondrial Inner Membrane ◽  
Inner Membrane Protein

scholarly journals Identification of the essential yeast protein MIM17, an integral mitochondrial inner membrane protein involved in protein import

FEBS Letters ◽  
1994 ◽  
Vol 349 (2) ◽  
pp. 215-221 ◽  
Author(s):  
Ammy C. Maarse ◽  
Jolanda Blom ◽  
Petra Keil ◽  
Nikolaus Pfanner ◽  
Michiel Meijer
Keyword(s):  
Membrane Protein ◽  
Protein Import ◽  
Yeast Protein ◽  
Inner Membrane ◽  
Mitochondrial Inner Membrane ◽  
Inner Membrane Protein

scholarly journals The uptake of silicic acid by rat liver mitochondria

1978 ◽  
Vol 172 (3) ◽  
pp. 557-568 ◽  
Author(s):  
R N Johnson ◽  
B E Volcani
Keyword(s):  
Silicic Acid ◽  
Diffusion Mechanism ◽  
Mitochondrial Protein ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Energy Status ◽  
Matrix Space ◽  
Inner Membrane ◽  
Simple Diffusion ◽  
Mitochondrial Inner Membrane

1. To gain insight into a putative role for mitochondria in silicon metabolism, mitochondrial uptake (by which it is meant the removal from the medium) of silicic acid [Si(OH)4] was studied under conditions minimizing SI(OH)4 polymerization. 2. Measurements of mitochondrial respiration and swelling indicated indirectly a significant uptake of Si(OH)4 as a weak acid, but this was not confirmed when 31Si(OH)4 was used as a tracer. 31Si(OH)4 occupied a mitochondrial volume similar to that of 3H2O and was relatively unaffected by mitochondrial energy status and by the pH gradient across the mitochondrial inner membrane. 3. Uptake was directly proportional to Si(OH)4 concentration in the range 0-3 mM. 4. The uptake consisted of two components: under all conditions examined, the greater quantity, amounting to 1-2nmol of Si(OH)4/mg of mitochondrial protein, was bound, a major portion of it external to the inner membrane, with the lesser quantity free within the matrix space. 5. Equilibration of 31Si(OH)4 between medium and matrix was a slow process, having a half-time of approx. 10 min at 22 degrees C. 6. Mersalyl and N-ethylmaleimide inhibited the uptake by preferentially lowering the amount of Si(OH)4 bound. Their action was somewhat variable, depending on the precise nature of the suspending medium, and suggesting that the bound material may represent polymerized forms of Si(OH)4. 7. It is concluded that Si(OH)4 may penetrate the mitochondrial inner membrane by a simple diffusion mechanism.

scholarly journals Targeting and assembly of the oxoglutarate carrier: general principles for biogenesis of carrier proteins of the mitochondrial inner membrane

1998 ◽  
Vol 333 (1) ◽  
pp. 151-158 ◽  
Author(s):  
Annamaria PALMISANO ◽  
Vincenzo ZARA ◽  
Angelika HÖNLINGER ◽  
Angelo VOZZA ◽  
Peter J. T. DEKKER ◽  
...  
Keyword(s):  
High Efficiency ◽  
Dependent Manner ◽  
Yeast Mitochondria ◽  
Inner Membrane ◽  
Mitochondrial Inner Membrane ◽  
Native Electrophoresis ◽  
Surface Receptor ◽  
Inner Membrane Protein ◽  
Oxoglutarate Carrier

We have studied the targeting and assembly of the 2-oxoglutarate carrier (OGC), an integral inner-membrane protein of mitochondria. The precursor of OGC, synthesized without a cleavable presequence, is transported into mitochondria in an ATP- and membrane potential-dependent manner. Import of the mammalian OGC occurs efficiently into both mammalian and yeast mitochondria. Targeting of OGC reveals a clear dependence on the mitochondrial surface receptor Tom70 (the 70 kDa subunit of the translocase of the outer mitochondrial membrane), whereas a cleavable preprotein depends on Tom20 (the 20 kDa subunit), supporting a model of specificity differences of the receptors and the existence of distinct targeting pathways to mitochondria. The assembly of minute amounts of OGC imported in vitro to the dimeric form can be monitored by blue native electrophoresis of digitonin-lysed mitochondria. The assembly of mammalian OGC and fungal ADP/ATP carrier occurs with high efficiency in both mammalian and yeast mitochondria. These findings indicate a dynamic behaviour of the carrier dimers in the mitochondrial inner membrane and suggest a high conservation of the assembly reactions from mammals to fungi.

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