Analysis of Mitochondrial Membrane Fusion GTPase OPA1 Expressed by the Expression System

2020 ◽  
pp. 115-127
Author(s):  
Tadato Ban ◽  
Naotada Ishihara
Keyword(s):  
Membrane Fusion ◽  
Mitochondrial Membrane ◽  
Expression System

scholarly journals Protection from α-Synuclein induced dopaminergic neurodegeneration by overexpression of the mitochondrial import receptor TOM20

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Briana R. De Miranda ◽  
Emily M. Rocha ◽  
Sandra L. Castro ◽  
J. Timothy Greenamyre
Keyword(s):  
Substantia Nigra ◽  
Mitochondrial Dysfunction ◽  
Dopaminergic Neurons ◽  
Mitochondrial Membrane ◽  
Expression System ◽  
Outer Mitochondrial Membrane ◽  
Mitochondrial Import ◽  
In Vivo Models ◽  
Dopaminergic Neurodegeneration ◽  
Import Receptor

AbstractDopaminergic neurons of the substantia nigra are selectively vulnerable to mitochondrial dysfunction, which is hypothesized to be an early and fundamental pathogenic mechanism in Parkinson’s disease (PD). Mitochondrial function depends on the successful import of nuclear-encoded proteins, many of which are transported through the TOM20–TOM22 outer mitochondrial membrane import receptor machinery. Recent data suggests that post-translational modifications of α-synuclein promote its interaction with TOM20 at the outer mitochondrial membrane and thereby inhibit normal protein import, leading to dysfunction, and death of dopaminergic neurons. As such, preservation of mitochondrial import in the face of α-synuclein accumulation might be a strategy to prevent dopaminergic neurodegeneration, however, this is difficult to assess using current in vivo models of PD. To this end, we established an exogenous co-expression system, utilizing AAV2 vectors to overexpress human α-synuclein and TOM20, individually or together, in the adult Lewis rat substantia nigra to assess whether TOM20 overexpression attenuates α-synuclein-induced dopaminergic neurodegeneration. Twelve weeks after viral injection, we observed that AAV2-TOM20 expression was sufficient to prevent loss of nigral dopaminergic neurons caused by AAV2-αSyn overexpression. The observed TOM20-mediated dopaminergic neuron preservation appeared to be due, in part, to the rescued expression (and presumed import) of nuclear-encoded mitochondrial electron transport chain proteins that were inhibited by α-synuclein overexpression. In addition, TOM20 overexpression rescued the expression of the chaperone protein GRP75/mtHSP70/mortalin, a stress-response protein involved in α-synuclein-induced injury. Collectively, these data indicate that TOM20 expression prevents α-synuclein-induced mitochondrial dysfunction, which is sufficient to rescue dopaminergic neurons in the adult rat brain.

scholarly journals Mitochondrial dynamics: overview of molecular mechanisms

2018 ◽  
Vol 62 (3) ◽  
pp. 341-360 ◽  
Author(s):  
Lisa Tilokani ◽  
Shun Nagashima ◽  
Vincent Paupe ◽  
Julien Prudent
Keyword(s):  
Membrane Fusion ◽  
Mitochondrial Membrane ◽  
Molecular Mechanisms ◽  
Calcium Influx ◽  
Mitochondrial Dynamics ◽  
Mitochondrial Fission ◽  
Membrane Lipid ◽  
Inner Mitochondrial Membrane ◽  
Step Process ◽  
Shape Distribution

Mitochondria are highly dynamic organelles undergoing coordinated cycles of fission and fusion, referred as ‘mitochondrial dynamics’, in order to maintain their shape, distribution and size. Their transient and rapid morphological adaptations are crucial for many cellular processes such as cell cycle, immunity, apoptosis and mitochondrial quality control. Mutations in the core machinery components and defects in mitochondrial dynamics have been associated with numerous human diseases. These dynamic transitions are mainly ensured by large GTPases belonging to the Dynamin family. Mitochondrial fission is a multi-step process allowing the division of one mitochondrion in two daughter mitochondria. It is regulated by the recruitment of the GTPase Dynamin-related protein 1 (Drp1) by adaptors at actin- and endoplasmic reticulum-mediated mitochondrial constriction sites. Drp1 oligomerization followed by mitochondrial constriction leads to the recruitment of Dynamin 2 to terminate membrane scission. Inner mitochondrial membrane constriction has been proposed to be an independent process regulated by calcium influx. Mitochondrial fusion is driven by a two-step process with the outer mitochondrial membrane fusion mediated by mitofusins 1 and 2 followed by inner membrane fusion, mediated by optic atrophy 1. In addition to the role of membrane lipid composition, several members of the machinery can undergo post-translational modifications modulating these processes. Understanding the molecular mechanisms controlling mitochondrial dynamics is crucial to decipher how mitochondrial shape meets the function and to increase the knowledge on the molecular basis of diseases associated with morphology defects. This article will describe an overview of the molecular mechanisms that govern mitochondrial fission and fusion in mammals.

scholarly journals Phospholipid Association Is Essential for Dynamin-related Protein Mgm1 to Function in Mitochondrial Membrane Fusion

2009 ◽  
Vol 284 (42) ◽  
pp. 28682-28686 ◽  
Author(s):  
Jarungjit Rujiviphat ◽  
Gabriela Meglei ◽  
John L. Rubinstein ◽  
G. Angus McQuibban
Keyword(s):  
Membrane Fusion ◽  
Mitochondrial Membrane ◽  
Related Protein

scholarly journals Protection from α-synuclein-induced dopaminergic neurodegeneration by overexpression of the mitochondrial import receptor TOM20 in the rat midbrain

2020 ◽  
Author(s):  
Briana R. De Miranda ◽  
Emily M. Rocha ◽  
Sandra Castro ◽  
J. Timothy Greenamyre
Keyword(s):  
Substantia Nigra ◽  
Mitochondrial Dysfunction ◽  
Dopaminergic Neurons ◽  
Mitochondrial Membrane ◽  
Protein Import ◽  
Expression System ◽  
Outer Mitochondrial Membrane ◽  
Mitochondrial Import ◽  
Dopaminergic Neurodegeneration ◽  
Import Receptor

Dopaminergic neurons of the substantia nigra are selectively vulnerable to mitochondrial dysfunction, which is hypothesized to be an early and fundamental pathogenic mechanism in Parkinson’s disease (PD). Mitochondrial function depends on the successful import of nuclear-encoded proteins, many of which are transported through the TOM20-TOM22 outer mitochondrial membrane import receptor machinery. Recent data suggests that post-translational modifications of α-synuclein promote its interaction with TOM20 at the outer mitochondrial membrane and thereby inhibit normal protein import, which leads to dysfunction and death of dopaminergic neurons. As such, preservation of mitochondrial import in the face of α-synuclein accumulation might be a strategy to prevent dopaminergic neurodegeneration, however, this is difficult to assess using current in vivo models of PD. To this end, we established an exogenous co-expression system, utilizing AAV2 vectors to overexpress human α-synuclein and TOM20, individually or together, in the adult Lewis rat substantia nigra in order to assess whether TOM20 overexpression attenuates α-synuclein-induced dopaminergic neurodegeneration. Twelve weeks after viral injection, we observed that AAV2-TOM20 expression was sufficient to prevent loss of nigral dopaminergic neurons caused by AAV2-αSyn overexpression. The observed TOM20-mediated dopaminergic neuron preservation appeared to be due, in part, to the rescued import of nuclear-encoded mitochondrial electron transport chain proteins that were inhibited by α-synuclein overexpression. In addition, TOM20 overexpression rescued the import of the chaperone protein GRP75/mtHSP70/mortalin, a stress-response protein involved in α-synuclein-induced injury. Collectively, these data indicate that TOM20 expression prevents α-synuclein-induced mitochondrial dysfunction, which is sufficient to rescue dopaminergic neurons in the adult rat brain.

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