Allosteric Modulation of Drp1 Mechanoenzyme Assembly and Mitochondrial Fission by the Variable Domain

Strack, Stefan; Cribbs, J. Thomas

doi:10.1074/jbc.m112.342105

Cited by 98 publications

(128 citation statements)

References 36 publications

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“…These intermediate states are observed after membrane scission and prior to the separation of the divided mitochondria mediated by opposed pulling forces likely exerted by the cytoskeleton. In agreement with this, membrane division at the middle point of the Drp1 filament has been reported previously in various publications (26,34), although without any mechanistic connection.…”

Section: Discussionsupporting

confidence: 90%

“…In agreement with this, lipids with negative intrinsic monolayer curvature increased Drp1 membrane tethering activity. Similarly, we observed comparable tethered structures in living cells during Drp1-mediated mitochondrial division, in agreement with previous results in mammal and yeast cells (9,13,22,31,34). Together, our findings support a molecular mechanism by which Drp1 promotes membrane fission by stabilizing membrane topologies involved in membrane fission.…”

supporting

confidence: 92%

“…Indeed, previous studies with GFP-tagged Drp1 have reported that Drp1 fission complexes remain associated with both ends of divided mitochondria (34). Similar observations have been made for Dnm1 in yeast (13).…”

Section: Quantitative Analysis Of Gtp and Lipid Composition Effects Osupporting

confidence: 79%

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Dynamin-related Protein 1 (Drp1) Promotes Structural Intermediates of Membrane Division

Ugarte‐Uribe

Müller

Otsuki

et al. 2014

Journal of Biological Chemistry

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Background: Drp1 mediates mitochondrial division via a poorly understood mechanism. Results: Drp1 promotes giant vesicle tethering and concentrates at contact sites in structures similar to those found in dividing mitochondria. Conclusion: Besides membrane constriction, Drp1 stabilizes structural intermediates of membrane division. Significance: This new role of Drp1 helps us understand mitochondrial biology.

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Section: Discussionsupporting

confidence: 90%

supporting

confidence: 92%

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Dynamin-related Protein 1 (Drp1) Promotes Structural Intermediates of Membrane Division

Ugarte‐Uribe

Müller

Otsuki

et al. 2014

Journal of Biological Chemistry

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“…Higher-order Self-assembly of Drp1 R376E Prohibits Functional Interactions with Mff-Given that Drp1-3 and ⌬VD GTPase activities were stimulated by Mff interactions in vitro, we sought to characterize the putative Mff binding-defective mutant, Drp1 R376E (40). This charge reversal was designed to disrupt an interaction interface between Drp1 and Mff, and Mff immunoprecipitation of Drp1 from HEK293 cells in the presence of a crosslinker was inhibited (40).…”

Section: G363dmentioning

confidence: 99%

“…This charge reversal was designed to disrupt an interaction interface between Drp1 and Mff, and Mff immunoprecipitation of Drp1 from HEK293 cells in the presence of a crosslinker was inhibited (40). The recently solved crystal structure of Drp1 reveals that Arg-376 is situated in close proximity to an assembly interface, interface 4, unique to Drp1 (22).…”

Section: G363dmentioning

confidence: 99%

Dynamin-related Protein 1 Oligomerization in Solution Impairs Functional Interactions with Membrane-anchored Mitochondrial Fission Factor

Clinton¹,

Francy²,

Ramachandran

et al. 2016

Journal of Biological Chemistry

113

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Mitochondrial fission is a crucial cellular process mediated by the mechanoenzymatic GTPase, dynamin-related protein 1 (Drp1). During mitochondrial division, Drp1 is recruited from the cytosol to the outer mitochondrial membrane by one, or several, integral membrane proteins. One such Drp1 partner protein, mitochondrial fission factor (Mff), is essential for mitochondrial division, but its mechanism of action remains unexplored. Previous studies have been limited by a weak interaction between Drp1 and Mff in vitro. Through refined in vitro reconstitution approaches and multiple independent assays, we show that removal of the regulatory variable domain (VD) in Drp1 enhances formation of a functional Drp1-Mff copolymer. This protein assembly exhibits greatly stimulated cooperative GTPase activity in solution. Moreover, when Mff was anchored to a lipid template, to mimic a more physiologic environment, significant stimulation of GTPase activity was observed with both WT and ⌬VD Drp1. Contrary to recent findings, we show that premature Drp1 self-assembly in solution impairs functional interactions with membrane-anchored Mff. Instead, dimeric Drp1 species are selectively recruited by Mff to initiate assembly of a functional fission complex. Correspondingly, we also found that the coiled-coil motif in Mff is not essential for Drp1 interactions, but rather serves to augment cooperative self-assembly of Drp1 proximal to the membrane. Taken together, our findings provide a mechanism wherein the multimeric states of both Mff and Drp1 regulate their collaborative interaction.Mitochondria undergo continuous cycles of fission and fusion to maintain a functional organelle network within eukaryotic cells. This mitochondrial network is crucial for ATP generation, apoptotic signaling, and calcium homeostasis. When the proper balance of mitochondrial dynamics is disrupted, mitochondrial dysfunction is observed (1, 2). This insult is associated with increased cell death in several human diseases, including neurodegenerative disorders (3, 4), ischemiareperfusion injury (5, 6), and glaucoma (7). Therefore, mitochondrial division has developed into a compelling therapeutic target for intervention with small molecule and peptide inhibitors that limit cell death in several of these pathologies (8 -13).The master regulator of mitochondrial fission, dynamin-related protein 1 (Drp1), 2 has been targeted in these diseases. Similar to other dynamin family members, Drp1 is a large GTPase that mediates membrane remodeling. The primary sequence of Drp1 is composed of four conserved regions (see Fig. 1A): the GTPase domain, middle domain, variable domain (VD), and GTPase effector domain (GED). Hydrolysis of GTP triggers conformational changes in Drp1 oligomers that generate the mechanical force needed to promote mitochondrial membrane scission (14, 15), and factors that inhibit Drp1 GTPase activity prevent mitochondrial division (8,16,17). The middle and GED domains promote Drp1 self-assembly, which is also critical for its role in facilitating...

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Mechano‐energetic aspects of Barth syndrome

Dudek

Maack

2021

J of Inher Metab Disea

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Energy‐demanding organs like the heart are strongly dependent on oxidative phosphorylation in mitochondria. Oxidative phosphorylation is governed by the respiratory chain located in the inner mitochondrial membrane. The inner mitochondrial membrane is the only cellular membrane with significant amounts of the phospholipid cardiolipin, and cardiolipin was found to directly interact with a number of essential protein complexes, including respiratory chain complexes I to V. An inherited defect in the biogenesis of cardiolipin causes Barth syndrome, which is associated with cardiomyopathy, skeletal myopathy, neutropenia and growth retardation. Energy conversion is dependent on reducing equivalents, which are replenished by oxidative metabolism in the Krebs cycle. Cardiolipin deficiency in Barth syndrome also affects Krebs cycle activity, metabolite transport and mitochondrial morphology. During excitation‐contraction coupling, calcium (Ca2+) released from the sarcoplasmic reticulum drives sarcomeric contraction. At the same time, Ca2+ influx into mitochondria drives the activation of Krebs cycle dehydrogenases and the regeneration of reducing equivalents. Reducing equivalents are essential not only for energy conversion, but also for maintaining a redox buffer, which is required to detoxify reactive oxygen species (ROS). Defects in CL may also affect Ca2+ uptake into mitochondria and thereby hamper energy supply and demand matching, but also detoxification of ROS. Here, we review the impact of cardiolipin deficiency on mitochondrial function in Barth syndrome and discuss potential therapeutic strategies.

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Allosteric Modulation of Drp1 Mechanoenzyme Assembly and Mitochondrial Fission by the Variable Domain

Cited by 98 publications

References 36 publications

Dynamin-related Protein 1 (Drp1) Promotes Structural Intermediates of Membrane Division

Dynamin-related Protein 1 (Drp1) Promotes Structural Intermediates of Membrane Division

Dynamin-related Protein 1 Oligomerization in Solution Impairs Functional Interactions with Membrane-anchored Mitochondrial Fission Factor

Mechano‐energetic aspects of Barth syndrome

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