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The EMBO Journal Feb 2016Vesicle release upon endocytosis requires membrane fission, catalyzed by the large GTPase dynamin. Dynamin contains five domains that together orchestrate its...
Vesicle release upon endocytosis requires membrane fission, catalyzed by the large GTPase dynamin. Dynamin contains five domains that together orchestrate its mechanochemical activity. Hydrogen-deuterium exchange coupled with mass spectrometry revealed global nucleotide- and membrane-binding-dependent conformational changes, as well as the existence of an allosteric relay element in the α2(S) helix of the dynamin stalk domain. As predicted from structural studies, FRET analyses detect large movements of the pleckstrin homology domain (PHD) from a 'closed' conformation docked near the stalk to an 'open' conformation able to interact with membranes. We engineered dynamin constructs locked in either the closed or open state by chemical cross-linking or deletion mutagenesis and showed that PHD movements function as a conformational switch to regulate dynamin self-assembly, membrane binding, and fission. This PHD conformational switch is impaired by a centronuclear myopathy-causing disease mutation, S619L, highlighting the physiological significance of its role in regulating dynamin function. Together, these data provide new insight into coordinated conformational changes that regulate dynamin function and couple membrane binding, oligomerization, and GTPase activity during dynamin-catalyzed membrane fission.
Topics: Cell Line; Dynamins; Fluorescence Resonance Energy Transfer; Guanosine Triphosphate; Humans; Hydrolysis; Intracellular Membranes; Magnetic Resonance Spectroscopy; Mutant Proteins; Protein Conformation; Protein Multimerization; Sequence Deletion
PubMed: 26783363
DOI: 10.15252/embj.201593477 -
Annual Review of Cell and Developmental... 2000Dynamin, a 100-kDa GTPase, is an essential component of vesicle formation in receptor-mediated endocytosis, synaptic vesicle recycling, caveolae internalization, and... (Review)
Review
Dynamin, a 100-kDa GTPase, is an essential component of vesicle formation in receptor-mediated endocytosis, synaptic vesicle recycling, caveolae internalization, and possibly vesicle trafficking in and out of the Golgi. In addition to the GTPase domain, dynamin also contains a pleckstrin homology domain (PH) implicated in membrane binding, a GTPase effector domain (GED) shown to be essential for self-assembly and stimulated GTPase activity, and a C-terminal proline-rich domain (PRD), which contains several SH3-binding sites. Dynamin partners bind to the PRD and may either stimulate dynamin's GTPase activity or target dynamin to the plasma membrane. Purified dynamin readily self-assembles into rings or spirals. This striking structural property supports the hypothesis that dynamin wraps around the necks of budding vesicles where it plays a key role in membrane fission. The focus of this review is on the relationship between the GTPase and self-assembly properties of dynamin and its cellular function.
Topics: Animals; Dynamins; GTP Phosphohydrolases; Humans; Membrane Fusion; Phosphorylation; Protein Structure, Tertiary
PubMed: 11031245
DOI: 10.1146/annurev.cellbio.16.1.483 -
Neurotherapeutics : the Journal of the... Oct 2018Dynamin 2 (DNM2) belongs to a family of large GTPases that are well known for mediating membrane fission by oligomerizing at the neck of membrane invaginations.... (Review)
Review
Dynamin 2 (DNM2) belongs to a family of large GTPases that are well known for mediating membrane fission by oligomerizing at the neck of membrane invaginations. Autosomal dominant mutations in the ubiquitously expressed DNM2 cause 2 discrete neuromuscular diseases: autosomal dominant centronuclear myopathy (ADCNM) and dominant intermediate Charcot-Marie-Tooth neuropathy (CMT). CNM and CMT mutations may affect DNM2 in distinct manners: CNM mutations may cause protein hyperactivity with elevated GTPase and fission activities, while CMT mutations could impair DNM2 lipid binding and activity. DNM2 is also a modifier of the X-linked and autosomal recessive forms of CNM, as DNM2 protein levels are upregulated in animal models and patient muscle samples. Strikingly, reducing DNM2 has been shown to revert muscle phenotypes in preclinical models of CNM. As DNM2 emerges as the key player in CNM pathogenesis, the role(s) of DNM2 in skeletal muscle remains unclear. This review aims to provide insights into potential pathomechanisms related to DNM2-CNM mutations, and discuss exciting outcomes of current and future therapeutic approaches targeting DNM2 hyperactivity.
Topics: Animals; Dynamin II; Dynamins; Humans; Muscle, Skeletal; Mutation; Neuromuscular Diseases
PubMed: 30426359
DOI: 10.1007/s13311-018-00686-0 -
International Journal of Molecular... Mar 2018The endosymbiosis of a free-living cyanobacterium into an ancestral eukaryote led to the evolution of the chloroplast (plastid) more than one billion years ago. Given... (Review)
Review
The endosymbiosis of a free-living cyanobacterium into an ancestral eukaryote led to the evolution of the chloroplast (plastid) more than one billion years ago. Given their independent origins, plastid proliferation is restricted to the binary fission of pre-existing plastids within a cell. In the last 25 years, the structure of the supramolecular machinery regulating plastid division has been discovered, and some of its component proteins identified. More recently, isolated plastid-division machineries have been examined to elucidate their structural and mechanistic details. Furthermore, complex studies have revealed how the plastid-division machinery morphologically transforms during plastid division, and which of its component proteins play a critical role in generating the contractile force. Identifying the three-dimensional structures and putative functional domains of the component proteins has given us hints about the mechanisms driving the machinery. Surprisingly, the mechanisms driving plastid division resemble those of mitochondrial division, indicating that these division machineries likely developed from the same evolutionary origin, providing a key insight into how endosymbiotic organelles were established. These findings have opened new avenues of research into organelle proliferation mechanisms and the evolution of organelles.
Topics: Arabidopsis Proteins; Chloroplasts; Dynamins; Organelle Biogenesis
PubMed: 29510533
DOI: 10.3390/ijms19030733 -
Cell Reports Aug 2015Membrane trafficking and spinogenesis contribute significantly to changes in synaptic strength during development and in various paradigms of synaptic plasticity....
Membrane trafficking and spinogenesis contribute significantly to changes in synaptic strength during development and in various paradigms of synaptic plasticity. GTPases of the dynamin family are key players regulating membrane trafficking. Here, we identify a brain-specific dynamin family GTPase, neurolastin (RNF112/Znf179), with closest homology to atlastin. We demonstrate that neurolastin has functional GTPase and RING domains, making it a unique protein identified with this multi-enzymatic domain organization. We also show that neurolastin is a peripheral membrane protein that localizes to endosomes and affects endosomal membrane dynamics via its RING domain. In addition, neurolastin knockout mice have fewer dendritic spines, and rescue of the wild-type phenotype requires both the GTPase and RING domains. Furthermore, we find fewer functional synapses and reduced paired pulse facilitation in neurolastin knockout mice. Thus, we identify neurolastin as a dynamin family GTPase that affects endosome size and spine density.
Topics: Animals; Dendrites; Dynamins; Endosomes; HeLa Cells; Humans; Mice; Mice, Knockout; Protein Structure, Tertiary; Rats; Rats, Sprague-Dawley; Synapses
PubMed: 26212327
DOI: 10.1016/j.celrep.2015.06.064 -
Hypertension (Dallas, Tex. : 1979) Jul 2020Endothelial inflammation and mitochondrial dysfunction have been implicated in cardiovascular diseases, yet, a unifying mechanism tying them together remains limited....
Endothelial inflammation and mitochondrial dysfunction have been implicated in cardiovascular diseases, yet, a unifying mechanism tying them together remains limited. Mitochondrial dysfunction is frequently associated with mitochondrial fission/fragmentation mediated by the GTPase Drp1 (dynamin-related protein 1). Nuclear factor (NF)-κB, a master regulator of inflammation, is implicated in endothelial dysfunction and resultant complications. Here, we explore a causal relationship between mitochondrial fission and NF-κB activation in endothelial inflammatory responses. In cultured endothelial cells, TNF-α (tumor necrosis factor-α) or lipopolysaccharide induces mitochondrial fragmentation. Inhibition of Drp1 activity or expression suppresses mitochondrial fission, NF-κB activation, vascular cell adhesion molecule-1 induction, and leukocyte adhesion induced by these proinflammatory factors. Moreover, attenuations of inflammatory leukocyte adhesion were observed in Drp1 heterodeficient mice as well as endothelial Drp1 silenced mice. Intriguingly, inhibition of the canonical NF-κB signaling suppresses endothelial mitochondrial fission. Mechanistically, NF-κB p65/RelA seems to mediate inflammatory mitochondrial fission in endothelial cells. In addition, the classical anti-inflammatory drug, salicylate, seems to maintain mitochondrial fission/fusion balance against TNF-α via inhibition of NF-κB. In conclusion, our results suggest a previously unknown mechanism whereby the canonical NF-κB cascade and a mitochondrial fission pathway interdependently regulate endothelial inflammation.
Topics: 3T3 Cells; Animals; Aorta; Cell Adhesion; Cells, Cultured; Dynamins; Endothelial Cells; Endothelium, Vascular; Leukocytes, Mononuclear; Membrane Proteins; Mice; Mitochondrial Dynamics; Mitochondrial Proteins; Mutation, Missense; NF-kappa B; Phosphorylation; Phosphoserine; Protein Processing, Post-Translational; Proteome; RNA Interference; RNA, Small Interfering; Rats; Sodium Salicylate; Tumor Necrosis Factor-alpha; Vascular Cell Adhesion Molecule-1; Vasculitis
PubMed: 32389075
DOI: 10.1161/HYPERTENSIONAHA.120.14686 -
Biochemical Society Transactions Oct 2009The GTPase dynamin is essential for CME (clathrin-mediated endocytosis), but its exact function and mechanism of action have been controversial. Here, we review findings... (Review)
Review
The GTPase dynamin is essential for CME (clathrin-mediated endocytosis), but its exact function and mechanism of action have been controversial. Here, we review findings that have led to the current models for dynamin function, either as a mechanochemical enzyme driving membrane fission or as a regulatory GTPase monitoring rate-limiting steps in CME. However, these models are not mutually exclusive and subsequent studies have provided evidence for both dynamin functions. Recent evidence derived from divergent in vivo and in vitro approaches suggests that dynamin plays a dual role in CME, functioning at early stages as a fidelity monitor to regulate clathrin-coated pit maturation and at later stages to directly catalyse membrane fission and clathrin-coated vesicle formation.
Topics: Animals; Clathrin; Dynamins; Endocytosis; GTP Phosphohydrolases; Intracellular Membranes; Microtubules
PubMed: 19754444
DOI: 10.1042/BST0371022 -
Nature Communications Jul 2023The large cytosolic GTPase, dynamin-related protein 1 (Drp1), mediates both physiological and pathological mitochondrial fission. Cell stress triggers Drp1 binding to...
The large cytosolic GTPase, dynamin-related protein 1 (Drp1), mediates both physiological and pathological mitochondrial fission. Cell stress triggers Drp1 binding to mitochondrial Fis1 and subsequently, mitochondrial fragmentation, ROS production, metabolic collapse, and cell death. Because Drp1 also mediates physiological fission by binding to mitochondrial Mff, therapeutics that inhibit pathological fission should spare physiological mitochondrial fission. P110, a peptide inhibitor of Drp1-Fis1 interaction, reduces pathology in numerous models of neurodegeneration, ischemia, and sepsis without blocking the physiological functions of Drp1. Since peptides have pharmacokinetic limitations, we set out to identify small molecules that mimic P110's benefit. We map the P110-binding site to a switch I-adjacent grove (SWAG) on Drp1. Screening for SWAG-binding small molecules identifies SC9, which mimics P110's benefits in cells and a mouse model of endotoxemia. We suggest that the SWAG-binding small molecules discovered in this study may reduce the burden of Drp1-mediated pathologies and potentially pathologies associated with other members of the GTPase family.
Topics: Animals; Mice; Allosteric Site; Disease Models, Animal; Dynamins; GTP Phosphohydrolases; Mitochondria; Mitochondrial Dynamics; Mitochondrial Proteins
PubMed: 37468472
DOI: 10.1038/s41467-023-40043-0 -
Trends in Cell Biology Apr 2021Mitochondria are dynamic organelles that undergo cycles of fission and fusion events depending on cellular requirements. During mitochondrial division, the GTPase... (Review)
Review
Mitochondria are dynamic organelles that undergo cycles of fission and fusion events depending on cellular requirements. During mitochondrial division, the GTPase dynamin-related protein-1 is recruited to endoplasmic reticulum (ER)-induced mitochondrial constriction sites where it drives fission. However, the events required to complete scission of mitochondrial membranes are not well understood. Here, we emphasize the recently described roles for Golgi-derived phosphatidylinositol 4-phosphate (PI4P)-containing vesicles in the last steps of mitochondrial division. We then propose how trans-Golgi network vesicles at mitochondria-ER contact sites and PI4P generation could mechanistically execute mitochondrial division, by recruiting PI4P effectors and/or the actin nucleation machinery. Finally, we speculate on mechanisms to explain why such a complex dance of different organelles is required to facilitate the remodelling of mitochondrial membranes.
Topics: Dynamins; Endoplasmic Reticulum; GTP Phosphohydrolases; Mitochondria; Mitochondrial Dynamics; Mitochondrial Membranes; Mitochondrial Proteins
PubMed: 33446409
DOI: 10.1016/j.tcb.2020.12.005 -
Biomedicine & Pharmacotherapy =... Sep 2023Mitochondrial dysfunction, especially in terms of mitochondrial dynamics, has been reported to be closely associated with neuronal outcomes and neurological impairment... (Review)
Review
Mitochondrial dysfunction, especially in terms of mitochondrial dynamics, has been reported to be closely associated with neuronal outcomes and neurological impairment in cerebral ischemia/hypoxia injury. Dynamin-related protein 1 (Drp1) is a cytoplasmic GTPase that mediates mitochondrial fission and participates in neuronal cell death, calcium signaling, and oxidative stress. The neuroprotective role of Drp1 inhibition has been confirmed in several central nervous system disease models, demonstrating that targeting Drp1 may shed light on novel approaches for the treatment of cerebral ischemia/hypoxia injury. In this review, we aimed to highlight the roles of Drp1 in programmed cell death, oxidative stress, mitophagy, and mitochondrial function to provide a better understanding of mitochondrial disturbances in cerebral ischemia/hypoxia injury, and we also summarize the advances in novel chemical compounds targeting Drp1 to provide new insights into potential therapies for cerebral ischemia/hypoxia injury.
Topics: Humans; Brain Ischemia; Dynamins; Hypoxia; Mitochondria; Neurons; Animals
PubMed: 37516018
DOI: 10.1016/j.biopha.2023.115247