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

Ugarte‐Uribe, Begoña; Müller, Hans‐Michael; Otsuki, Miki; Nickel, Walter; García‐Sáez, Ana J.

doi:10.1074/jbc.m114.575779

Cited by 62 publications

(74 citation statements)

References 76 publications

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“…In fact, the accompanying article (42) clearly shows that Mff stimulation of Drp1 activity is synergistic with CL stimulation. These results are congruent with previous reports of VD interactions with CL that promote Drp1 recruitment to lipid bilayers (21,(23)(24)(25). Given that CL has been shown to stabilize dimeric Drp1 at the lipid surface to promote Drp1 self-assembly (23), we propose that CL interactions at the membrane directly promote Drp1 dimer interactions with Mff (Fig.…”

Section: Discussionsupporting

confidence: 82%

“…Initially, the role of the VD was examined based on its apparent proximity to the membrane as well as its ability to interact with CL (21,23,25). This proposed location would also place it directly adjacent to receptor proteins on the OMM to promote intermolecular interactions.…”

Section: Discussionmentioning

confidence: 99%

“…In vitro, the addition of negatively charged lipids increases Drp1 self-assembly to form larger helical assemblies that represent the contractile apparatus of mitochondrial fission (20), and these functional polymers exhibit stimulated GTPase activity (14,(21)(22)(23). The VD has recently been shown to act as a negative regulator of Drp1 self-assembly (14) with an inherent ability to interact with cardiolipin (CL) present in mitochondrial membranes (21,(23)(24)(25). Studies in yeast have shown that the VD is required for interactions with a mitochondrial adaptor protein (26), but the partner protein identified in that study is not conserved in higher eukaryotes, which suggests that the role of the VD may have evolved in higher organisms to accommodate different regulatory interactions in the cytosol and at the surface of mitochondria.…”

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confidence: 99%

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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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Section: Discussionsupporting

confidence: 82%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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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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“…The VD has been proposed to interact directly with negatively charged lipid (20,21). Nevertheless, the ⌬VD mutant was found to assemble on both negatively charged liposomes used in these studies.…”

Section: Discussionmentioning

confidence: 65%

“…The middle and GED domains promote self-assembly through oligomerization interaction interfaces (19). The role of the VD is currently debated, but recent studies have identified a role in lipid interactions (20,21). Collectively, these domains work in concert to promote cycles of protein assembly and disassembly at sites of membrane remodeling.…”

mentioning

confidence: 99%

The Mechanoenzymatic Core of Dynamin-related Protein 1 Comprises the Minimal Machinery Required for Membrane Constriction

Francy¹,

Alvarez²,

Zhou³

et al. 2015

Journal of Biological Chemistry

103

137

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Background: Drp1 oligomerization and activity is critical for mitochondrial fission. Results: GTP hydrolysis is required for Drp1 constriction of lipid bilayers. The variable domain of Drp1 regulates self-assembly and is not required for constriction of lipid bilayers. Conclusion:The core machinery of Drp1 is sufficient to mediate lipid assembly, constriction, and disassembly. Significance: Characterization of the mechanoenzymatic properties of Drp1 advances our understanding of mitochondrial fission.

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The variable domain from dynamin‐related protein 1 promotes liquid–liquid phase separation that enhances its interaction with cardiolipin‐containing membranes

Posey,

Ross,

Bagheri

et al. 2023

Protein Science

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Dynamins are an essential superfamily of mechanoenzymes that remodel membranes and often contain a “variable domain” important for regulation. For the mitochondrial fission dynamin, dynamin‐related protein 1, a regulatory role for the variable domain is demonstrated by gain‐ and loss‐of‐function mutations, yet the basis for this is unclear. Here, the isolated variable domain is shown to be intrinsically disordered and undergo a cooperative transition in the stabilizing osmolyte trimethylamine N‐oxide. However, the osmolyte‐induced state is not folded and surprisingly appears as a condensed state. Other co‐solutes including known molecular crowder Ficoll PM 70, also induce a condensed state. Fluorescence recovery after photobleaching experiments reveal this state to be liquid‐like indicating the variable domain undergoes a liquid–liquid phase separation under crowding conditions. These crowding conditions also enhance binding to cardiolipin, a mitochondrial lipid, which appears to promote phase separation. Since dynamin‐related protein 1 is found assembled into discrete punctate structures on the mitochondrial surface, the inference from the present work is that these structures might arise from a condensed state involving the variable domain that may enable rapid tuning of mechanoenzyme assembly necessary for fission.This article is protected by copyright. All rights reserved.

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

Cited by 62 publications

References 76 publications

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

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

The Mechanoenzymatic Core of Dynamin-related Protein 1 Comprises the Minimal Machinery Required for Membrane Constriction

The variable domain from dynamin‐related protein 1 promotes liquid–liquid phase separation that enhances its interaction with cardiolipin‐containing membranes

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