scholarly journals Mitochondrial lipid transport and biosynthesis: A complex balance

2016 ◽  
Vol 214 (1) ◽  
pp. 9-11 ◽  
Author(s):  
Bruno Mesmin
Keyword(s):  
Metabolic Enzymes ◽  
Lipid Transport ◽  
Contact Site ◽  
Inner Membrane ◽  
Cell Biol ◽  
Mitochondrial Lipid ◽  
Mitochondrial Complexes ◽  
Mitochondrial Lipids

Little is known about how mitochondrial lipids reach inner membrane–localized metabolic enzymes for phosphatidylethanolamine synthesis. Aaltonen et al. (2016. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201602007) and Miyata et al. (2016. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201601082) now report roles for two mitochondrial complexes, Ups2–Mdm35 and mitochondrial contact site and cristae organizing system, in the biosynthesis and transport of mitochondrial lipids.

scholarly journals Pathways shaping the mitochondrial inner membrane

Open Biology ◽  
2021 ◽  
Vol 11 (12) ◽  
Author(s):  
Till Klecker ◽  
Benedikt Westermann
Keyword(s):  
Atp Synthase ◽  
Lipid Composition ◽  
Mitochondrial Membrane ◽  
Contact Site ◽  
Dimer Formation ◽  
Inner Membrane ◽  
Mitochondrial Inner Membrane ◽  
Mitochondrial Atp Synthase ◽  
Evolutionarily Conserved ◽  
Mitochondrial Lipid

Mitochondria are complex organelles with two membranes. Their architecture is determined by characteristic folds of the inner membrane, termed cristae. Recent studies in yeast and other organisms led to the identification of four major pathways that cooperate to shape cristae membranes. These include dimer formation of the mitochondrial ATP synthase, assembly of the mitochondrial contact site and cristae organizing system (MICOS), inner membrane remodelling by a dynamin-related GTPase (Mgm1/OPA1), and modulation of the mitochondrial lipid composition. In this review, we describe the function of the evolutionarily conserved machineries involved in mitochondrial cristae biogenesis with a focus on yeast and present current models to explain how their coordinated activities establish mitochondrial membrane architecture.

scholarly journals Incredibly close—A newly identified peroxisome–ER contact site in humans

2017 ◽  
Vol 216 (2) ◽  
pp. 287-289 ◽  
Author(s):  
Maya Schuldiner ◽  
Einat Zalckvar
Keyword(s):  
Endoplasmic Reticulum ◽  
Membrane Protein ◽  
Binding Protein ◽  
Human Cells ◽  
Metabolic Processes ◽  
Contact Site ◽  
Cell Biol ◽  
Associated Proteins

Peroxisomes are tiny organelles that control important and diverse metabolic processes via their interplay with other organelles, including the endoplasmic reticulum (ER). In this issue, Costello et al. (2017. J. Cell Biol. https://doi.org/10.1083/jcb.201607055) and Hua et al. (2017. J. Cell Biol. https://doi.org/10.1083/jcb.201608128) identify a peroxisome–ER contact site in human cells held together by a tethering complex of VAPA/B (vesicle-associated membrane protein–associated proteins A/B) and ACBD5 (acyl Co-A binding protein 5).

scholarly journals MICOS coordinates with respiratory complexes and lipids to establish mitochondrial inner membrane architecture

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Jonathan R Friedman ◽  
Arnaud Mourier ◽  
Justin Yamada ◽  
J Michael McCaffery ◽  
Jodi Nunnari
Keyword(s):  
Inner Membrane ◽  
Functional Roles ◽  
Respiratory Complexes ◽  
Growth Defects ◽  
Mitochondrial Inner Membrane ◽  
Complex Functions ◽  
Primary Determinant ◽  
Mitochondrial Defects ◽  
Mitochondrial Lipid ◽  
Redundant Functions

The conserved MICOS complex functions as a primary determinant of mitochondrial inner membrane structure. We address the organization and functional roles of MICOS and identify two independent MICOS subcomplexes: Mic27/Mic10/Mic12, whose assembly is dependent on respiratory complexes and the mitochondrial lipid cardiolipin, and Mic60/Mic19, which assembles independent of these factors. Our data suggest that MICOS subcomplexes independently localize to cristae junctions and are connected via Mic19, which functions to regulate subcomplex distribution, and thus, potentially also cristae junction copy number. MICOS subunits have non-redundant functions as the absence of both MICOS subcomplexes results in more severe morphological and respiratory growth defects than deletion of single MICOS subunits or subcomplexes. Mitochondrial defects resulting from MICOS loss are caused by misdistribution of respiratory complexes in the inner membrane. Together, our data are consistent with a model where MICOS, mitochondrial lipids and respiratory complexes coordinately build a functional and correctly shaped mitochondrial inner membrane.

scholarly journals Uniform nomenclature for the mitochondrial contact site and cristae organizing system

2014 ◽  
Vol 204 (7) ◽  
pp. 1083-1086 ◽  
Author(s):  
Nikolaus Pfanner ◽  
Martin van der Laan ◽  
Paolo Amati ◽  
Roderick A. Capaldi ◽  
Amy A. Caudy ◽  
...  
Keyword(s):  
Large Protein ◽  
Contact Site ◽  
Inner Membrane ◽  
Future Studies ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
Mitochondrial Inner Membrane ◽  
Large Protein Complex ◽  
Membrane Contact ◽  
Uniform Nomenclature

The mitochondrial inner membrane contains a large protein complex that functions in inner membrane organization and formation of membrane contact sites. The complex was variably named the mitochondrial contact site complex, mitochondrial inner membrane organizing system, mitochondrial organizing structure, or Mitofilin/Fcj1 complex. To facilitate future studies, we propose to unify the nomenclature and term the complex “mitochondrial contact site and cristae organizing system” and its subunits Mic10 to Mic60.

scholarly journals The Cirque du Soleil of Golgi membrane dynamics

2009 ◽  
Vol 186 (2) ◽  
pp. 169-171 ◽  
Author(s):  
Vytas A. Bankaitis
Keyword(s):  
Lysophosphatidic Acid ◽  
Metabolic Enzymes ◽  
Membrane Dynamics ◽  
Membrane Remodeling ◽  
Golgi Membrane ◽  
Tubule Formation ◽  
Cirque Du Soleil ◽  
Cell Biol

The role of lipid metabolic enzymes in Golgi membrane remodeling is a subject of intense interest. Now, in this issue, Schmidt and Brown (2009. J. Cell Biol. doi:10.1083/jcb.200904147) report that lysophosphatidic acid–specific acyltransferase, LPAAT3, contributes to Golgi membrane dynamics by suppressing tubule formation.

Mitochondrial lipid transport at a glance

2013 ◽  
Vol 126 (23) ◽  
pp. 5317-5323 ◽  
Author(s):  
M. Scharwey ◽  
T. Tatsuta ◽  
T. Langer
Keyword(s):  
Lipid Transport ◽  
Mitochondrial Lipid

Novel intracellular functions of apolipoproteins: the ApoO protein family as constituents of the Mitofilin/MINOS complex determines cristae morphology in mitochondria

2014 ◽  
Vol 395 (3) ◽  
pp. 285-296 ◽  
Author(s):  
Sebastian Koob ◽  
Andreas S. Reichert
Keyword(s):  
Morphological Changes ◽  
Dynamic Network ◽  
Lipid Transport ◽  
Site Formation ◽  
Current View ◽  
Dynamic Nature ◽  
Contact Site ◽  
Mitochondrial Inner Membrane ◽  
Human Disorders

Abstract Mitochondria exist in a highly dynamic network that is constantly altered by fusion and fission events depending on various factors such as cellular bioenergetic state and cell cycle. Next to this dynamic nature of the organelle, its cristae membrane also undergoes drastic morphological changes upon physiological or pathological alterations. The Mitofilin/mitochondrial inner membrane organizing system (MINOS) complex was recently reported to ensure mitochondrial architecture and crista junction integrity. Several subunits of this complex are linked to a diverse set of neurological human disorders. Recently, two apolipoproteins, ApoO (APOO) and ApoO-like (APOOL) were suggested to represent constituents of the mammalian Mitofilin/MINOS complex. APOOL was shown to bind the mitochondrial phospholipid cardiolipin (CL) and to interact physically with this complex. In this review we highlight the current view on the mammalian Mitofilin/MINOS complex and focus on APOOL and the role of CL in determining cristae morphology. We will discuss possible functions of the Mitofilin/MINOS complex on lipid transport, on assembly of respiratory supercomplexes, on F1FO-ATP synthase organization, on contact site formation, and on trapping CL within the cristae subcompartment.

scholarly journals Mic60 exhibits a coordinated clustered distribution along and across yeast and mammalian mitochondria

2019 ◽  
Vol 116 (20) ◽  
pp. 9853-9858 ◽  
Author(s):  
Stefan Stoldt ◽  
Till Stephan ◽  
Daniel C. Jans ◽  
Christian Brüser ◽  
Felix Lange ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
Interaction Network ◽  
Yeast Mitochondria ◽  
Contact Site ◽  
Inner Membrane ◽  
Mitochondrial Inner Membrane ◽  
Mammalian Mitochondria ◽  
Interaction Partners ◽  
A Subunit

Mitochondria are tubular double-membrane organelles essential for eukaryotic life. They form extended networks and exhibit an intricate inner membrane architecture. The MICOS (mitochondrial contact site and cristae organizing system) complex, crucial for proper architecture of the mitochondrial inner membrane, is localized primarily at crista junctions. Harnessing superresolution fluorescence microscopy, we demonstrate that Mic60, a subunit of the MICOS complex, as well as several of its interaction partners are arranged into intricate patterns in human and yeast mitochondria, suggesting an ordered distribution of the crista junctions. We show that Mic60 forms clusters that are preferentially localized in the inner membrane at two opposing sides of the mitochondrial tubules so that they form extended opposing distribution bands. These Mic60 distribution bands can be twisted, resulting in a helical arrangement. Focused ion beam milling-scanning electron microscopy showed that in yeast the twisting of the opposing distribution bands is echoed by the folding of the inner membrane. We show that establishment of the Mic60 distribution bands is largely independent of the cristae morphology. We suggest that Mic60 is part of an extended multiprotein interaction network that scaffolds mitochondria.

scholarly journals Shutting down the power supply for DNA repair in cancer cells

2017 ◽  
Vol 216 (2) ◽  
pp. 295-297 ◽  
Author(s):  
Marcel A.T.M. van Vugt
Keyword(s):  
Dna Repair ◽  
Homologous Recombination ◽  
Cancer Cells ◽  
Cancer Cell ◽  
Power Supply ◽  
Metabolic Enzymes ◽  
Phosphoglycerate Mutase ◽  
Dna Damaging Agents ◽  
Cell Biol

Phosphoglycerate mutase 1 (PGAM1) functions in glycolysis. In this issue, Qu et al. (2017. J. Cell Biol. https://doi.org/10.1083/jcb.201607008) show that PGAM1 inactivation leads to nucleotide depletion, which causes defective homologous recombination–mediated DNA repair, suggesting that targeting metabolic enzymes increases cancer cell susceptibility to DNA damaging agents.

scholarly journals Lipid homeostasis in mitochondria

2020 ◽  
Vol 401 (6-7) ◽  
pp. 821-833
Author(s):  
Yasushi Tamura ◽  
Shin Kawano ◽  
Toshiya Endo
Keyword(s):  
Lipid Homeostasis ◽  
Structural Basis ◽  
Lipid Transfer ◽  
Lipid Transfer Proteins ◽  
Lipid Trafficking ◽  
Contact Sites ◽  
Mitochondrial Lipid ◽  
Proper Functions ◽  
Mitochondrial Lipids

AbstractMitochondria are surrounded by the two membranes, the outer and inner membranes, whose lipid compositions are optimized for proper functions and structural organizations of mitochondria. Although a part of mitochondrial lipids including their characteristic lipids, phosphatidylethanolamine and cardiolipin, are synthesized within mitochondria, their precursor lipids and other lipids are transported from other organelles, mainly the ER. Mitochondrially synthesized lipids are re-distributed within mitochondria and to other organelles, as well. Recent studies pointed to the important roles of inter-organelle contact sites in lipid trafficking between different organelle membranes. Identification of Ups/PRELI proteins as lipid transfer proteins shuttling between the mitochondrial outer and inner membranes established a part of the molecular and structural basis of the still elusive intra-mitochondrial lipid trafficking.

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