1
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Miyoshi H, Otomo M, Takahashi K. Clomipramine inhibits dynamin GTPase activity by L-α-phosphatidyl-L-serine stimulation. J Biochem 2023; 174:267-272. [PMID: 37137298 DOI: 10.1093/jb/mvad038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 04/21/2023] [Indexed: 05/05/2023] Open
Abstract
Three dynamin isoforms play critical roles in clathrin-dependent endocytosis. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) enters host cells via clathrin-dependent endocytosis. We previously reported that 3-(3-chloro-10,11-dihydro-5H-dibenzo[b,f]azepin-5-yl)-N,N-dimethylpropan-1-amine (clomipramine) inhibits the GTPase activity of dynamin 1, which is in mainly neuron. Therefore, we investigated whether clomipramine inhibits the activity of other dynamin isoforms in this study. We found that, similar to its inhibitory effect on dynamin 1, clomipramine inhibited the l-α-phosphatidyl-l-serine-stimulated GTPase activity of dynamin 2, which is expressed ubiquitously, and dynamin 3, which is expressed in the lung. Inhibition of GTPase activity raises the possibility that clomipramine can suppress SARS-CoV-2 entry into host cells.
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Affiliation(s)
- Hiroshi Miyoshi
- Department of Microbiology, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae, Kawasaki 216-8511, Japan
| | - Masahiro Otomo
- Department of Neuropsychiatry, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae, Kawasaki 216-8511, Japan
| | - Kiyofumi Takahashi
- Department of Neuropsychiatry, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae, Kawasaki 216-8511, Japan
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2
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Yamada H, Abe T, Nagaoka H, Takashima E, Nitta R, Yamamoto M, Takei K. Recruitment of Irgb6 to the membrane is a direct trigger for membrane deformation. Front Cell Infect Microbiol 2022; 12:992198. [PMID: 36159643 PMCID: PMC9504060 DOI: 10.3389/fcimb.2022.992198] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 08/12/2022] [Indexed: 11/13/2022] Open
Abstract
Irgb6 is a member of interferon γ-induced immunity related GTPase (IRG), and one of twenty “effector” IRGs, which coordinately attack parasitophorous vacuole membrane (PVM), causing death of intracellular pathogen. Although Irgb6 plays a pivotal role as a pioneer in the process of PVM disruption, the direct effect of Irgb6 on membrane remained to be elucidated. Here, we utilized artificial lipid membranes to reconstitute Irgb6-membrane interaction in vitro, and revealed that Irgb6 directly deformed the membranes. Liposomes incubated with recombinant Irgb6 were drastically deformed generating massive tubular protrusions in the absence of guanine nucleotide, or with GMP-PNP. Liposome deformation was abolished by incubating with Irgb6-K275A/R371A, point mutations at membrane targeting residues. The membrane tubules generated by Irgb6 were mostly disappeared by the addition of GTP or GDP, which are caused by detachment of Irgb6 from membrane. Binding of Irgb6 to the membrane, which was reconstituted in vitro using lipid monolayer, was stimulated at GTP-bound state. Irgb6 GTPase activity was stimulated by the presence of liposomes more than eightfold. Irgb6 GTPase activity in the absence of membrane was also slightly stimulated, by lowering ionic strength, or by increasing protein concentration, indicating synergistic stimulation of the GTPase activity. These results suggest that membrane targeting of Irgb6 and resulting membrane deformation does not require GTP, but converting into GTP-bound state is crucial for detaching Irgb6 from the membrane, which might coincident with local membrane disruption.
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Affiliation(s)
- Hiroshi Yamada
- Department of Neuroscience, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
- *Correspondence: Hiroshi Yamada, ; Kohji Takei,
| | - Tadashi Abe
- Department of Neuroscience, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Hikaru Nagaoka
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Eizo Takashima
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Ryo Nitta
- Division of Structural Medicine and Anatomy, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Masahiro Yamamoto
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka University, Suita, Japan
| | - Kohji Takei
- Department of Neuroscience, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
- *Correspondence: Hiroshi Yamada, ; Kohji Takei,
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3
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Aryal CM, Bui NN, Song L, Pan J. The N-terminal helices of amphiphysin and endophilin have different capabilities of membrane remodeling. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183907. [PMID: 35247332 DOI: 10.1016/j.bbamem.2022.183907] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 02/17/2022] [Accepted: 02/24/2022] [Indexed: 06/14/2023]
Abstract
Amphiphysin and endophilin are two members of the N-BAR protein family. We have reported membrane interactions of the helix 0 of endophilin (H0-Endo). Here we investigate membrane modulations caused by the helix 0 of amphiphysin (H0-Amph). Electron paramagnetic resonance (EPR) spectroscopy was used to explore membrane properties. H0-Amph was found to reduce lipid mobility, make the membrane interior more polar, and decrease lipid chain orientational order. The EPR data also showed that for anionic membranes, H0-Endo acted as a more potent modulator. For instance, at peptide-to-lipid (P/L) ratio of 1/20, the peak-to-peak splitting was increased by 0.27 G and 1.89 G by H0-Amph and H0-Endo, respectively. Similarly, H0-Endo caused a larger change in the bilayer polarity than H0-Amph (30% versus 12% at P/L = 1/20). At P/L = 1/50, the chain orientational order was decreased by 26% and 66% by H0-Amph and H0-Endo, respectively. The different capabilities were explained by considering hydrophobicity score distributions. We employed atomic force microscopy to investigate membrane structural changes. Both peptides caused the formation of micron-sized holes. Interestingly, only H0-Amph induced membrane fusion as evidenced by the formation of high-rise regions. Lastly, experiments of giant unilamellar vesicles showed that H0-Amph and H0-Endo generated thin tubules and miniscule vesicles, respectively. Together, our studies showed that both helices are effective in altering membrane properties; the observed changes might be important for membrane curvature induction. Importantly, comparisons between the two peptides revealed that the degree of membrane remodeling is dependent on the sequence of the N-terminal helix of the N-BAR protein family.
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Affiliation(s)
- Chinta M Aryal
- Department of Physics, University of South Florida, Tampa, FL 33620, United States of America; MED-Cancer & Cell Biology, University of Cincinnati, Cincinnati, OH 45267
| | - Nhat Nguyen Bui
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, United States of America
| | - Likai Song
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, United States of America.
| | - Jianjun Pan
- Department of Physics, University of South Florida, Tampa, FL 33620, United States of America.
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4
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Lu CH, Pedram K, Tsai CT, Jones T, Li X, Nakamoto ML, Bertozzi CR, Cui B. Membrane curvature regulates the spatial distribution of bulky glycoproteins. Nat Commun 2022; 13:3093. [PMID: 35654773 PMCID: PMC9163104 DOI: 10.1038/s41467-022-30610-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 05/10/2022] [Indexed: 01/11/2023] Open
Abstract
The glycocalyx is a shell of heavily glycosylated proteins and lipids distributed on the cell surface of nearly all cell types. Recently, it has been found that bulky transmembrane glycoproteins such as MUC1 can modulate membrane shape by inducing membrane protrusions. In this work, we examine the reciprocal relationship of how membrane shape affects MUC1's spatial distribution on the cell membrane and its biological significance. By employing nanopatterned surfaces and membrane-sculpting proteins to manipulate membrane curvature, we show that MUC1 avoids positively-curved membranes (membrane invaginations) and accumulates on negatively-curved membranes (membrane protrusions). MUC1's curvature sensitivity is dependent on the length and the extent of glycosylation of its ectodomain, with large and highly glycosylated forms preferentially staying out of positive curvature. Interestingly, MUC1's avoidance of positive membrane curvature enables it to escape from endocytosis and being removed from the cell membrane. These findings also suggest that the truncation of MUC1's ectodomain, often observed in breast and ovarian cancers, may enhance its endocytosis and potentiate its intracellular accumulation and signaling.
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Affiliation(s)
- Chih-Hao Lu
- grid.168010.e0000000419368956Department of Chemistry, Stanford University, Stanford, CA 94305 USA
| | - Kayvon Pedram
- grid.168010.e0000000419368956Department of Chemistry, Stanford University, Stanford, CA 94305 USA ,grid.443970.dPresent Address: Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147 USA
| | - Ching-Ting Tsai
- grid.168010.e0000000419368956Department of Chemistry, Stanford University, Stanford, CA 94305 USA
| | - Taylor Jones
- grid.168010.e0000000419368956Department of Chemistry, Stanford University, Stanford, CA 94305 USA
| | - Xiao Li
- grid.168010.e0000000419368956Department of Chemistry, Stanford University, Stanford, CA 94305 USA ,grid.43169.390000 0001 0599 1243Present Address: School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an, China
| | - Melissa L. Nakamoto
- grid.168010.e0000000419368956Department of Chemistry, Stanford University, Stanford, CA 94305 USA
| | - Carolyn R. Bertozzi
- grid.168010.e0000000419368956Department of Chemistry, Stanford University, Stanford, CA 94305 USA ,grid.168010.e0000000419368956Stanford ChEM-H, Stanford University, Stanford, CA 94305 USA ,grid.168010.e0000000419368956Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305 USA
| | - Bianxiao Cui
- grid.168010.e0000000419368956Department of Chemistry, Stanford University, Stanford, CA 94305 USA
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5
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Cheng X, Chen K, Dong B, Yang M, Filbrun SL, Myoung Y, Huang TX, Gu Y, Wang G, Fang N. Dynamin-dependent vesicle twist at the final stage of clathrin-mediated endocytosis. Nat Cell Biol 2021; 23:859-869. [PMID: 34253896 PMCID: PMC8355216 DOI: 10.1038/s41556-021-00713-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 06/09/2021] [Indexed: 12/11/2022]
Abstract
Dynamin plays an important role in clathrin-mediated endocytosis (CME) by cutting the neck of nascent vesicles from the cell membrane. Here through using gold nanorods as cargos to image dynamin action during live CME, we show that near the peak of dynamin accumulation, the cargo-containing vesicles always exhibit abrupt, right-handed rotations that finish in a short time (~0.28 s). The large and quick twist, herein named the super twist, is the result of the coordinated dynamin helix action upon GTP hydrolysis. After the super twist, the rotational freedom of the vesicle drastically increases, accompanied with simultaneous or delayed translational movement, indicating that it detaches from the cell membrane. These observations suggest that dynamin-mediated scission involves a large torque generated by coordinated actions of multiple dynamins in the helix, which is the main driving force for vesicle scission.
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Affiliation(s)
- Xiaodong Cheng
- Department of Chemistry, Georgia State University, Atlanta, GA, USA.,State Key Laboratory of Physical Chemistry of Solid Surfaces, Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - Kuangcai Chen
- Department of Chemistry, Georgia State University, Atlanta, GA, USA
| | - Bin Dong
- Department of Chemistry, Georgia State University, Atlanta, GA, USA
| | - Meek Yang
- Department of Chemistry, Georgia State University, Atlanta, GA, USA
| | - Seth L Filbrun
- Department of Chemistry, Georgia State University, Atlanta, GA, USA
| | - Yong Myoung
- Department of Chemistry, Georgia State University, Atlanta, GA, USA
| | - Teng-Xiang Huang
- Department of Chemistry, Georgia State University, Atlanta, GA, USA
| | - Yan Gu
- The Bristol-Myers Squibb Company, Devens, MA, USA
| | - Gufeng Wang
- Department of Chemistry, Georgia State University, Atlanta, GA, USA.
| | - Ning Fang
- Department of Chemistry, Georgia State University, Atlanta, GA, USA. .,State Key Laboratory of Physical Chemistry of Solid Surfaces, Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China.
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6
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Fujise K, Okubo M, Abe T, Yamada H, Nishino I, Noguchi S, Takei K, Takeda T. Mutant BIN1-Dynamin 2 complexes dysregulate membrane remodeling in the pathogenesis of centronuclear myopathy. J Biol Chem 2021; 296:100077. [PMID: 33187981 PMCID: PMC7949082 DOI: 10.1074/jbc.ra120.015184] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 11/10/2020] [Accepted: 11/13/2020] [Indexed: 11/08/2022] Open
Abstract
Membrane remodeling is required for dynamic cellular processes such as cell division, polarization, and motility. BAR domain proteins and dynamins are key molecules in membrane remodeling that work together for membrane deformation and fission. In striated muscles, sarcolemmal invaginations termed T-tubules are required for excitation-contraction coupling. BIN1 and DNM2, which encode a BAR domain protein BIN1 and dynamin 2, respectively, have been reported to be causative genes of centronuclear myopathy (CNM), a hereditary degenerative disease of skeletal muscle, and deformation of T-tubules is often observed in the CNM patients. However, it remains unclear how BIN1 and dynamin 2 are implicated in T-tubule biogenesis and how mutations in these molecules cause CNM to develop. Here, using an in cellulo reconstitution assay, we demonstrate that dynamin 2 is required for stabilization of membranous structures equivalent to T-tubules. GTPase activity of wild-type dynamin 2 is suppressed through interaction with BIN1, whereas that of the disease-associated mutant dynamin 2 remains active due to lack of the BIN1-mediated regulation, thus causing aberrant membrane remodeling. Finally, we show that in cellulo aberrant membrane remodeling by mutant dynamin 2 variants is correlated with their enhanced membrane fission activities, and the results can explain severity of the symptoms in patients. Thus, this study provides molecular insights into dysregulated membrane remodeling triggering the pathogenesis of DNM2-related CNM.
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MESH Headings
- Adaptor Proteins, Signal Transducing/genetics
- Adaptor Proteins, Signal Transducing/metabolism
- Adaptor Proteins, Signal Transducing/physiology
- Animals
- Blotting, Western
- Dynamin II/genetics
- Dynamin II/metabolism
- HEK293 Cells
- Humans
- Immunoprecipitation
- Microscopy, Fluorescence
- Muscle, Skeletal/metabolism
- Myopathies, Structural, Congenital/genetics
- Myopathies, Structural, Congenital/metabolism
- Nanotubes/chemistry
- Nuclear Proteins/genetics
- Nuclear Proteins/metabolism
- Tumor Suppressor Proteins/genetics
- Tumor Suppressor Proteins/metabolism
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Affiliation(s)
- Kenshiro Fujise
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Mariko Okubo
- National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira, Tokyo, Japan; Department of Pediatrics, The University of Tokyo, Tokyo, Japan
| | - Tadashi Abe
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Hiroshi Yamada
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Ichizo Nishino
- National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira, Tokyo, Japan
| | - Satoru Noguchi
- National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira, Tokyo, Japan
| | - Kohji Takei
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
| | - Tetsuya Takeda
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
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7
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Kretschmer S, Ganzinger KA, Franquelim HG, Schwille P. Synthetic cell division via membrane-transforming molecular assemblies. BMC Biol 2019; 17:43. [PMID: 31126285 PMCID: PMC6533746 DOI: 10.1186/s12915-019-0665-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Reproduction, i.e. the ability to produce new individuals from a parent organism, is a hallmark of living matter. Even the simplest forms of reproduction require cell division: attempts to create a designer cell therefore should include a synthetic cell division machinery. In this review, we will illustrate how nature solves this task, describing membrane remodelling processes in general and focusing on bacterial cell division in particular. We discuss recent progress made in their in vitro reconstitution, identify open challenges, and suggest how purely synthetic building blocks could provide an additional and attractive route to creating artificial cell division machineries.
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8
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Ganzinger KA, Schwille P. More from less - bottom-up reconstitution of cell biology. J Cell Sci 2019; 132:132/4/jcs227488. [PMID: 30718262 DOI: 10.1242/jcs.227488] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The ultimate goal of bottom-up synthetic biology is recreating life in its simplest form. However, in its quest to find the minimal functional units of life, this field contributes more than its main aim by also offering a range of tools for asking, and experimentally approaching, biological questions. This Review focusses on how bottom-up reconstitution has furthered our understanding of cell biology. Studying cell biological processes in vitro has a long tradition, but only recent technological advances have enabled researchers to reconstitute increasingly complex biomolecular systems by controlling their multi-component composition and their spatiotemporal arrangements. We illustrate this progress using the example of cytoskeletal processes. Our understanding of these has been greatly enhanced by reconstitution experiments, from the first in vitro experiments 70 years ago to recent work on minimal cytoskeleton systems (including this Special Issue of Journal of Cell Science). Importantly, reconstitution approaches are not limited to the cytoskeleton field. Thus, we also discuss progress in other areas, such as the shaping of biomembranes and cellular signalling, and prompt the reader to add their subfield of cell biology to this list in the future.
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Affiliation(s)
- Kristina A Ganzinger
- Physics of Cellular Interactions Group, AMOLF, 1098 XG Amsterdam, The Netherlands
| | - Petra Schwille
- Department Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
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9
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Damián-Zamacona S, García-González V, Avila-Barrientos LP, Delgado-Coello B, Reyes-Grajeda JP, Mas-Oliva J. Cell survival regulation during receptor-mediated endocytosis of chemically-modified lipoproteins associated to the formation of an Amphiphysin 2 (Bin1)/c-Myc complex. Biochem Biophys Res Commun 2018; 505:365-371. [PMID: 30253944 DOI: 10.1016/j.bbrc.2018.09.121] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 09/18/2018] [Indexed: 11/18/2022]
Abstract
Amphiphysin 2 and members of the BAR-domain family of proteins participate in a wide array of cellular processes including cell cycle and endocytosis. Given that amphiphysin 2 is related to diverse cell responses as a result of metabolic stress, we investigated in macrophages whether oxidative stress originated by the internalization of oxidized low density lipoproteins (oxLDL) affect both, the expression of amphiphysin 2 and its binding partner c-Myc. Here we report that under oxidative stress, a complex formation between amphiphysin 2(Bin1) and c-Myc allows the cell to develop a novel survival equilibrium state established between cell proliferation and cell death. We propose that under conditions of oxidative stress given by the internalization of oxLDL, macrophages employ the formation of the amphiphysin 2(Bin1)/c-Myc complex as a control mechanism to initially avoid the process of cell death in an attempt to prolong cell survival.
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Affiliation(s)
- Salvador Damián-Zamacona
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Victor García-González
- Departamento de Bioquímica, Facultad de Medicina Mexicali, Universidad Autónoma de Baja California, Mexicali, Baja California, Mexico
| | | | - Blanca Delgado-Coello
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | | | - Jaime Mas-Oliva
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico.
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10
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Somasundaram A, Taraska JW. Local protein dynamics during microvesicle exocytosis in neuroendocrine cells. Mol Biol Cell 2018; 29:1891-1903. [PMID: 29874123 PMCID: PMC6085826 DOI: 10.1091/mbc.e17-12-0716] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Calcium-triggered exocytosis is key to many physiological processes, including neurotransmitter and hormone release by neurons and endocrine cells. Dozens of proteins regulate exocytosis, yet the temporal and spatial dynamics of these factors during vesicle fusion remain unclear. Here we use total internal reflection fluorescence microscopy to visualize local protein dynamics at single sites of exocytosis of small synaptic-like microvesicles in live cultured neuroendocrine PC12 cells. We employ two-color imaging to simultaneously observe membrane fusion (using vesicular acetylcholine ACh transporter tagged to pHluorin) and the dynamics of associated proteins at the moments surrounding exocytosis. Our experiments show that many proteins, including the SNAREs syntaxin1 and VAMP2, the SNARE modulator tomosyn, and Rab proteins, are preclustered at fusion sites and rapidly lost at fusion. The ATPase N-ethylmaleimide–sensitive factor is locally recruited at fusion. Interestingly, the endocytic Bin-Amphiphysin-Rvs domain–containing proteins amphiphysin1, syndapin2, and endophilins are dynamically recruited to fusion sites and slow the loss of vesicle membrane-bound cargo from fusion sites. A similar effect on vesicle membrane protein dynamics was seen with the overexpression of the GTPases dynamin1 and dynamin2. These results suggest that proteins involved in classical clathrin-mediated endocytosis can regulate exocytosis of synaptic-like microvesicles. Our findings provide insights into the dynamics, assembly, and mechanistic roles of many key factors of exocytosis and endocytosis at single sites of microvesicle fusion in live cells.
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Affiliation(s)
- Agila Somasundaram
- Laboratory of Molecular Biophysics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Justin W Taraska
- Laboratory of Molecular Biophysics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
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11
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12
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Takeda T, Kozai T, Yang H, Ishikuro D, Seyama K, Kumagai Y, Abe T, Yamada H, Uchihashi T, Ando T, Takei K. Dynamic clustering of dynamin-amphiphysin helices regulates membrane constriction and fission coupled with GTP hydrolysis. eLife 2018; 7:30246. [PMID: 29357276 PMCID: PMC5780043 DOI: 10.7554/elife.30246] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Accepted: 12/18/2017] [Indexed: 01/16/2023] Open
Abstract
Dynamin is a mechanochemical GTPase essential for membrane fission during clathrin-mediated endocytosis. Dynamin forms helical complexes at the neck of clathrin-coated pits and their structural changes coupled with GTP hydrolysis drive membrane fission. Dynamin and its binding protein amphiphysin cooperatively regulate membrane remodeling during the fission, but its precise mechanism remains elusive. In this study, we analyzed structural changes of dynamin-amphiphysin complexes during the membrane fission using electron microscopy (EM) and high-speed atomic force microscopy (HS-AFM). Interestingly, HS-AFM analyses show that the dynamin-amphiphysin helices are rearranged to form clusters upon GTP hydrolysis and membrane constriction occurs at protein-uncoated regions flanking the clusters. We also show a novel function of amphiphysin in size control of the clusters to enhance biogenesis of endocytic vesicles. Our approaches using combination of EM and HS-AFM clearly demonstrate new mechanistic insights into the dynamics of dynamin-amphiphysin complexes during membrane fission. The nerve cells that make up a nervous system connect at junctions known as synapses. When a nerve impulse reaches the end of the cell, membrane-bound packages called vesicles fuse with the surface membrane and release their contents to the outside. The contents, namely chemicals called neurotransmitters, then travels across the synapse, relaying the signal to the next cell. Nerve cells can fire many times per second. The membrane from fused vesicles must be retrieved from the surface membrane and recycled to make new vesicles, ready to transmit more signals across the synapse. Many proteins at these sites are involved in folding the fused membrane back into the cell, constricting the opening, and eventually pinching off the new vesicles – a process known as endocytosis. Two proteins named dynamin and amphiphysin cooperate in this process, but their precise mechanism remained elusive. Dynamin is a protein that acts like a motor; it breaks down a molecule called GTP to release energy. Previous studies have seen that dynamin-amphiphysin complexes join end to end to form long helical structures. Takeda et al. have now looked at how the structure of the helices changes during endocytosis. This revealed that the dynamin-amphiphysin helices rearrange to form clusters when the GTP is broken down. Further analysis showed that the folded membrane becomes constricted at regions that are not coated with the clusters of dynamin-amphiphysin helices. Takeda et al. also discovered that amphiphysin controls the size of the clusters to help make the new vesicles more uniform. The gene for dynamin is altered in a number of disorders affecting the nervous system and muscles, including epileptic encephalopathy, Charcot-Marie-Tooth disease and congenital myopathy. Moreover, a neurological disorder characterized by muscle stiffness (known as Stiff-person syndrome) occurs when an individual’s immune system mistakenly attacks the amphiphysin protein. As such, these new findings will not only help scientists to better understand the process of endocytosis, but they will also give new insight into a number of human diseases.
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Affiliation(s)
- Tetsuya Takeda
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Toshiya Kozai
- Department of Physics, College of Science and Engineering, Kanazawa University, Kanazawa, Japan
| | - Huiran Yang
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Daiki Ishikuro
- Department of Physics, College of Science and Engineering, Kanazawa University, Kanazawa, Japan
| | - Kaho Seyama
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Yusuke Kumagai
- Department of Physics, College of Science and Engineering, Kanazawa University, Kanazawa, Japan
| | - Tadashi Abe
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Hiroshi Yamada
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Takayuki Uchihashi
- CREST, JST, Saitama, Japan.,Department of Physics, School of Science, Nagoya University, Nagoya, Japan
| | - Toshio Ando
- CREST, JST, Saitama, Japan.,Bio-AFM Frontier Research Center, College of Science and Engineering, Kanazawa University, Kanazawa, Japan
| | - Kohji Takei
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.,CREST, JST, Saitama, Japan
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13
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Candiello E, Mishra R, Schmidt B, Jahn O, Schu P. Differential regulation of synaptic AP-2/clathrin vesicle uncoating in synaptic plasticity. Sci Rep 2017; 7:15781. [PMID: 29150658 PMCID: PMC5694008 DOI: 10.1038/s41598-017-16055-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 10/24/2017] [Indexed: 11/09/2022] Open
Abstract
AP-1/σ1B-deficiency causes X-linked intellectual disability. AP-1/σ1B -/- mice have impaired synaptic vesicle recycling, fewer synaptic vesicles and enhanced endosome maturation mediated by AP-1/σ1A. Despite defects in synaptic vesicle recycling synapses contain two times more endocytic AP-2 clathrin-coated vesicles. We demonstrate increased formation of two classes of AP-2/clathrin coated vesicles. One which uncoats readily and a second with a stabilised clathrin coat. Coat stabilisation is mediated by three molecular mechanisms: reduced recruitment of Hsc70 and synaptojanin1 and enhanced μ2/AP-2 phosphorylation and activation. Stabilised AP-2 vesicles are enriched in the structural active zone proteins Git1 and stonin2 and synapses contain more Git1. Endocytosis of the synaptic vesicle exocytosis regulating Munc13 isoforms are differentially effected. Regulation of synaptic protein endocytosis by the differential stability of AP-2/clathrin coats is a novel molecular mechanism of synaptic plasticity.
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Affiliation(s)
- Ermes Candiello
- Department of Cellular Biochemistry, University Medical Center Goettingen, Georg-August-University Göttingen, Humboldtallee 23, 37073, Göttingen, Germany
| | - Ratnakar Mishra
- Department of Cellular Biochemistry, University Medical Center Goettingen, Georg-August-University Göttingen, Humboldtallee 23, 37073, Göttingen, Germany
| | - Bernhard Schmidt
- Department of Cellular Biochemistry, University Medical Center Goettingen, Georg-August-University Göttingen, Humboldtallee 23, 37073, Göttingen, Germany
| | - Olaf Jahn
- The Max-Planck-Institute for Experimental Medicine, Proteomics, Hermann-Rein-Str. 3, 37073, Göttingen, Germany
| | - Peter Schu
- Department of Cellular Biochemistry, University Medical Center Goettingen, Georg-August-University Göttingen, Humboldtallee 23, 37073, Göttingen, Germany.
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14
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Galli V, Sebastian R, Moutel S, Ecard J, Perez F, Roux A. Uncoupling of dynamin polymerization and GTPase activity revealed by the conformation-specific nanobody dynab. eLife 2017; 6:25197. [PMID: 29022874 PMCID: PMC5658065 DOI: 10.7554/elife.25197] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 10/11/2017] [Indexed: 01/28/2023] Open
Abstract
Dynamin is a large GTPase that forms a helical collar at the neck of endocytic pits, and catalyzes membrane fission (Schmid and Frolov, 2011; Ferguson and De Camilli, 2012). Dynamin fission reaction is strictly dependent on GTP hydrolysis, but how fission is mediated is still debated (Antonny et al., 2016): GTP energy could be spent in membrane constriction required for fission, or in disassembly of the dynamin polymer to trigger fission. To follow dynamin GTP hydrolysis at endocytic pits, we generated a conformation-specific nanobody called dynab, that binds preferentially to the GTP hydrolytic state of dynamin-1. Dynab allowed us to follow the GTPase activity of dynamin-1 in real-time. We show that in fibroblasts, dynamin GTP hydrolysis occurs as stochastic bursts, which are randomly distributed relatively to the peak of dynamin assembly. Thus, dynamin disassembly is not coupled to GTPase activity, supporting that the GTP energy is primarily spent in constriction.
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Affiliation(s)
- Valentina Galli
- Department of Biochemistry, University of Geneva, Geneva, Switzerland
| | - Rafael Sebastian
- Department of Computer Sciences, Universidad de Valencia, Valencia, Spain
| | - Sandrine Moutel
- Institut Curie, PSL Research University, Paris, France.,Translational Department, Institut Curie, Paris, France
| | - Jason Ecard
- Institut Curie, PSL Research University, Paris, France
| | - Franck Perez
- Institut Curie, PSL Research University, Paris, France
| | - Aurélien Roux
- Department of Biochemistry, University of Geneva, Geneva, Switzerland.,Swiss National Centre for Competence in Research Programme Chemical Biology, Geneva, Switzerland
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15
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Hohendahl A, Talledge N, Galli V, Shen PS, Humbert F, De Camilli P, Frost A, Roux A. Structural inhibition of dynamin-mediated membrane fission by endophilin. eLife 2017; 6:26856. [PMID: 28933693 PMCID: PMC5663480 DOI: 10.7554/elife.26856] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 09/20/2017] [Indexed: 01/19/2023] Open
Abstract
Dynamin, which mediates membrane fission during endocytosis, binds endophilin and other members of the Bin-Amphiphysin-Rvs (BAR) protein family. How endophilin influences endocytic membrane fission is still unclear. Here, we show that dynamin-mediated membrane fission is potently inhibited in vitro when an excess of endophilin co-assembles with dynamin around membrane tubules. We further show by electron microscopy that endophilin intercalates between turns of the dynamin helix and impairs fission by preventing trans interactions between dynamin rungs that are thought to play critical roles in membrane constriction. In living cells, overexpression of endophilin delayed both fission and transferrin uptake. Together, our observations suggest that while endophilin helps shape endocytic tubules and recruit dynamin to endocytic sites, it can also block membrane fission when present in excess by inhibiting inter-dynamin interactions. The sequence of recruitment and the relative stoichiometry of the two proteins may be critical to regulated endocytic fission.
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Affiliation(s)
- Annika Hohendahl
- Biochemistry Department, University of Geneva, Geneva, Switzerland
| | - Nathaniel Talledge
- Department of Biochemistry and Biophysics, University of California, San Francisco, United States.,California Institute for Quantitative Biomedical Research, University of California, San Francisco, United States.,Department of Biochemistry, University of Utah, Salt Lake City, United States.,Chan Zuckerberg Biohub, San Francisco, United States
| | - Valentina Galli
- Biochemistry Department, University of Geneva, Geneva, Switzerland
| | - Peter S Shen
- Department of Biochemistry, University of Utah, Salt Lake City, United States
| | - Frédéric Humbert
- Biochemistry Department, University of Geneva, Geneva, Switzerland
| | - Pietro De Camilli
- Department of Neuroscience, Yale University School of Medicine, New Haven, United States.,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, United States.,Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, United States.,Department of Cell Biology, Yale University School of Medicine, New Haven, United States.,Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, United States
| | - Adam Frost
- Department of Biochemistry and Biophysics, University of California, San Francisco, United States.,California Institute for Quantitative Biomedical Research, University of California, San Francisco, United States.,Department of Biochemistry, University of Utah, Salt Lake City, United States.,Chan Zuckerberg Biohub, San Francisco, United States
| | - Aurélien Roux
- Biochemistry Department, University of Geneva, Geneva, Switzerland.,Swiss National Centre for Competence in Research Programme Chemical Biology, Geneva, Switzerland
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16
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Simunovic M, Manneville JB, Renard HF, Evergren E, Raghunathan K, Bhatia D, Kenworthy AK, Voth GA, Prost J, McMahon HT, Johannes L, Bassereau P, Callan-Jones A. Friction Mediates Scission of Tubular Membranes Scaffolded by BAR Proteins. Cell 2017. [PMID: 28648660 PMCID: PMC5576516 DOI: 10.1016/j.cell.2017.05.047] [Citation(s) in RCA: 148] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Membrane scission is essential for intracellular trafficking. While BAR domain proteins such as endophilin have been reported in dynamin-independent scission of tubular membrane necks, the cutting mechanism has yet to be deciphered. Here, we combine a theoretical model, in vitro, and in vivo experiments revealing how protein scaffolds may cut tubular membranes. We demonstrate that the protein scaffold bound to the underlying tube creates a frictional barrier for lipid diffusion; tube elongation thus builds local membrane tension until the membrane undergoes scission through lysis. We call this mechanism friction-driven scission (FDS). In cells, motors pull tubes, particularly during endocytosis. Through reconstitution, we show that motors not only can pull out and extend protein-scaffolded tubes but also can cut them by FDS. FDS is generic, operating even in the absence of amphipathic helices in the BAR domain, and could in principle apply to any high-friction protein and membrane assembly.
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Affiliation(s)
- Mijo Simunovic
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 75005 Paris, France; Sorbonne Universités, UPMC University Paris 06, 75005 Paris, France; Department of Chemistry, Institute for Biophysical Dynamics, James Franck Institute, The University of Chicago, 5735 S. Ellis Avenue, Chicago, IL 60637, USA
| | - Jean-Baptiste Manneville
- Subcellular Structure and Cellular Dynamics Unit, Institut Curie, PSL Research University, CNRS UMR144, 75005 Paris, France
| | - Henri-François Renard
- Chemical Biology of Membranes and Therapeutic Delivery Unit, Institut Curie, PSL Research University, CNRS UMR3666, INSERM U1143, 75005 Paris, France
| | - Emma Evergren
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK; Centre for Cancer Research and Cell Biology, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK
| | - Krishnan Raghunathan
- Department of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, 718 Light Hall, Nashville, TN 37232, USA
| | - Dhiraj Bhatia
- Chemical Biology of Membranes and Therapeutic Delivery Unit, Institut Curie, PSL Research University, CNRS UMR3666, INSERM U1143, 75005 Paris, France
| | - Anne K Kenworthy
- Department of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, 718 Light Hall, Nashville, TN 37232, USA
| | - Gregory A Voth
- Department of Chemistry, Institute for Biophysical Dynamics, James Franck Institute, The University of Chicago, 5735 S. Ellis Avenue, Chicago, IL 60637, USA
| | - Jacques Prost
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 75005 Paris, France; Sorbonne Universités, UPMC University Paris 06, 75005 Paris, France; Mechanobiology Institute, National University of Singapore, Singapore 119077, Singapore
| | - Harvey T McMahon
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Ludger Johannes
- Chemical Biology of Membranes and Therapeutic Delivery Unit, Institut Curie, PSL Research University, CNRS UMR3666, INSERM U1143, 75005 Paris, France
| | - Patricia Bassereau
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 75005 Paris, France; Sorbonne Universités, UPMC University Paris 06, 75005 Paris, France.
| | - Andrew Callan-Jones
- Laboratoire Matière et Systèmes Complexes, CNRS UMR7057, 75205 Paris, France.
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17
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Chatterjee M, Hurley LC, Tainsky MA. Paraneoplastic antigens as biomarkers for early diagnosis of ovarian cancer. Gynecol Oncol Rep 2017; 21:37-44. [PMID: 28653032 PMCID: PMC5476453 DOI: 10.1016/j.gore.2017.06.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 05/30/2017] [Accepted: 06/05/2017] [Indexed: 12/24/2022] Open
Abstract
Paraneoplastic syndromes are a group of rare disorders that can be triggered by an abnormal immune response to proteins from tumors of the lung, ovary, lymphatics, or breast. Paraneoplastic clinical syndromes affect < 1% of patients with cancer; however, the frequency of subclinical levels of paraneoplastic autoantibodies in asymptomatic patients with cancer is unknown. Numerous studies have reported that ovarian cancer patients show signs of paraneoplastic neurological syndromes (PNSs) before or after their cancers are diagnosed. PNSs arise from a tumor-elicited immune response against onconeural antigens that are shared by tissues of nervous system, muscle, and tumor cells. Studies on the serum IgGs obtained from ovarian cancer patients have indicated the presence of onconeural antibodies in the absence of any PNS symptoms. The occurrence of PNSs is low in ovarian cancer patients and it can be accompanied by onconeural antibodies. The diagnosis of PNSs is accompanied by a suspicion of a malignant tumor such that neurologists typically refer such patients for a tumor diagnostic workup. There will be tremendous utility if subclinical levels (without paraneoplastic neurological symptoms or myositis) of these autoantibodies to paraneoplastic antigens can be exploited to screen asymptomatic high-risk patients for ovarian cancer, and used as biomarkers in immunoassays for the early detection or recurrence of ovarian cancer. Ovarian cancer overall survival is likely to be improved with early detection. Therefore, a panel of onconeural antigens that can detect paraneoplastic autoantibodies in patient sera should provide diagnostic utility for an earlier therapeutic intervention. Here we review the usefulness of PNS and other paraneoplastic syndromes and their association with paraneoplastic antigens to exploit these autoantibody biomarkers to form diagnostic multi-analyte panels for early detection of ovarian cancer.
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Affiliation(s)
- Madhumita Chatterjee
- Department of Oncology, Wayne State University School of Medicine, Detroit, MI 48201, United States
| | - Laura C Hurley
- Department of Oncology, Wayne State University School of Medicine, Detroit, MI 48201, United States.,Cancer Biology Graduate Program, Wayne State University School of Medicine, Detroit, MI 48201, United States
| | - Michael A Tainsky
- Department of Oncology, Wayne State University School of Medicine, Detroit, MI 48201, United States.,Cancer Biology Graduate Program, Wayne State University School of Medicine, Detroit, MI 48201, United States.,Molecular Therapeutics Program, Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201, United States.,Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, United States
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18
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Antonny B, Burd C, De Camilli P, Chen E, Daumke O, Faelber K, Ford M, Frolov VA, Frost A, Hinshaw JE, Kirchhausen T, Kozlov MM, Lenz M, Low HH, McMahon H, Merrifield C, Pollard TD, Robinson PJ, Roux A, Schmid S. Membrane fission by dynamin: what we know and what we need to know. EMBO J 2016; 35:2270-2284. [PMID: 27670760 PMCID: PMC5090216 DOI: 10.15252/embj.201694613] [Citation(s) in RCA: 349] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 07/25/2016] [Indexed: 12/04/2022] Open
Abstract
The large GTPase dynamin is the first protein shown to catalyze membrane fission. Dynamin and its related proteins are essential to many cell functions, from endocytosis to organelle division and fusion, and it plays a critical role in many physiological functions such as synaptic transmission and muscle contraction. Research of the past three decades has focused on understanding how dynamin works. In this review, we present the basis for an emerging consensus on how dynamin functions. Three properties of dynamin are strongly supported by experimental data: first, dynamin oligomerizes into a helical polymer; second, dynamin oligomer constricts in the presence of GTP; and third, dynamin catalyzes membrane fission upon GTP hydrolysis. We present the two current models for fission, essentially diverging in how GTP energy is spent. We further discuss how future research might solve the remaining open questions presently under discussion.
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Affiliation(s)
- Bruno Antonny
- CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Université de Nice Sophia-Antipolis, Valbonne, France
| | - Christopher Burd
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Pietro De Camilli
- Departments of Neuroscience and Cell Biology, Howard Hughes Medical Institute and Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, CT, USA
| | - Elizabeth Chen
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Oliver Daumke
- Department of Crystallography, Max-Delbrück Centrum für Molekulare Medizin, Berlin, Germany
| | - Katja Faelber
- Department of Crystallography, Max-Delbrück Centrum für Molekulare Medizin, Berlin, Germany
| | - Marijn Ford
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Vadim A Frolov
- Biofisika Institute (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country, Leioa, Spain.,IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - Adam Frost
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
| | - Jenny E Hinshaw
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD, USA
| | - Tom Kirchhausen
- Departments of Cell Biology and Pediatrics, Harvard Medical School, Boston, MA, USA.,Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Michael M Kozlov
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Martin Lenz
- LPTMS, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Orsay, France
| | - Harry H Low
- Department of Life Sciences, Imperial College, London, UK
| | | | | | - Thomas D Pollard
- Department of Molecular Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Phillip J Robinson
- Cell Signalling Unit, Children's Medical Research Institute, The University of Sydney, Westmead, NSW, Australia
| | - Aurélien Roux
- Department of Biochemistry and Swiss NCCR Chemical Biology, University of Geneva, Geneva 4, Switzerland
| | - Sandra Schmid
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX, USA
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19
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Hohendahl A, Roux A, Galli V. Structural insights into the centronuclear myopathy-associated functions of BIN1 and dynamin 2. J Struct Biol 2016; 196:37-47. [PMID: 27343996 PMCID: PMC5039012 DOI: 10.1016/j.jsb.2016.06.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 06/20/2016] [Accepted: 06/21/2016] [Indexed: 01/10/2023]
Abstract
Centronuclear myopathies (CNMs) are genetic diseases whose symptoms are muscle weakness and atrophy (wasting) and centralised nuclei. Recent human genetic studies have isolated several groups of mutations. Among them, many are found in two interacting proteins essential to clathrin-mediated endocytosis, dynamin and the BIN-Amphiphysin-Rvs (BAR) protein BIN1/amphiphysin 2. In this review, by using structural and functional data from the study of endocytosis mainly, we discuss how the CNM mutations could affect the structure and the function of these ubiquitous proteins and cause the muscle-specific phenotype. The literature shows that both proteins are involved in the plasma membrane tubulation required for T-tubule biogenesis. However, this system also requires the regulation of the dynamin-mediated membrane fission, and the formation of a stable protein-scaffold to maintain the T-tubule structure. We discuss how the specific functions, isoforms and partners (myotubularin in particular) of these two proteins can lead to the establishment of muscle-specific features.
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Affiliation(s)
- Annika Hohendahl
- Biochemistry Department, University of Geneva, CH-1211 Geneva, Switzerland
| | - Aurélien Roux
- Biochemistry Department, University of Geneva, CH-1211 Geneva, Switzerland; Swiss National Centre for Competence in Research Programme Chemical Biology, CH-1211 Geneva, Switzerland.
| | - Valentina Galli
- Biochemistry Department, University of Geneva, CH-1211 Geneva, Switzerland
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20
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Yoshida Y, Niwa H, Honsho M, Itoyama A, Fujiki Y. Pex11mediates peroxisomal proliferation by promoting deformation of the lipid membrane. Biol Open 2015; 4:710-21. [PMID: 25910939 PMCID: PMC4467191 DOI: 10.1242/bio.201410801] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pex11p family proteins are key players in peroxisomal fission, but their molecular mechanisms remains mostly unknown. In the present study, overexpression of Pex11pβ caused substantial vesiculation of peroxisomes in mammalian cells. This vesicle formation was dependent on dynamin-like protein 1 (DLP1) and mitochondrial fission factor (Mff), as knockdown of these proteins diminished peroxisomal fission after Pex11pβ overexpression. The fission-deficient peroxisomes exhibited an elongated morphology, and peroxisomal marker proteins, such as Pex14p or matrix proteins harboring peroxisomal targeting signal 1, were discernible in a segmented staining pattern, like beads on a string. Endogenous Pex11pβ was also distributed a striped pattern, but which was not coincide with Pex14p and PTS1 matrix proteins. Altered morphology of the lipid membrane was observed when recombinant Pex11p proteins were introduced into proteo-liposomes. Constriction of proteo-liposomes was observed under confocal microscopy and electron microscopy, and the reconstituted Pex11pβ protein localized to the membrane constriction site. Introducing point mutations into the N-terminal amphiphathic helix of Pex11pβ strongly reduced peroxisomal fission, and decreased the oligomer formation. These results suggest that Pex11p contributes to the morphogenesis of the peroxisomal membrane, which is required for subsequent fission by DLP1.
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Affiliation(s)
- Yumi Yoshida
- Department of Biology, Faculty of Sciences, Kyushu University Graduate School, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
| | - Hajime Niwa
- Department of Biology, Faculty of Sciences, Kyushu University Graduate School, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
| | - Masanori Honsho
- Department of Biology, Faculty of Sciences, Kyushu University Graduate School, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
| | - Akinori Itoyama
- Graduate School of Systems Life Sciences, Kyushu University Graduate School, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
| | - Yukio Fujiki
- Department of Biology, Faculty of Sciences, Kyushu University Graduate School, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan Graduate School of Systems Life Sciences, Kyushu University Graduate School, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan International Institute for Carbon-Neutral Energy Research (ICNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
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21
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Pinot M, Vanni S, Pagnotta S, Lacas-Gervais S, Payet LA, Ferreira T, Gautier R, Goud B, Antonny B, Barelli H. Lipid cell biology. Polyunsaturated phospholipids facilitate membrane deformation and fission by endocytic proteins. Science 2014; 345:693-7. [PMID: 25104391 DOI: 10.1126/science.1255288] [Citation(s) in RCA: 262] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Phospholipids (PLs) with polyunsaturated acyl chains are extremely abundant in a few specialized cellular organelles such as synaptic vesicles and photoreceptor discs, but their effect on membrane properties is poorly understood. Here, we found that polyunsaturated PLs increased the ability of dynamin and endophilin to deform and vesiculate synthetic membranes. When cells incorporated polyunsaturated fatty acids into PLs, the plasma membrane became more amenable to deformation by a pulling force and the rate of endocytosis was accelerated, in particular, under conditions in which cholesterol was limiting. Molecular dynamics simulations and biochemical measurements indicated that polyunsaturated PLs adapted their conformation to membrane curvature. Thus, by reducing the energetic cost of membrane bending and fission, polyunsaturated PLs may help to support rapid endocytosis.
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Affiliation(s)
- Mathieu Pinot
- Institut de Pharmacologie Moléculaire et Cellulaire, Université Nice Sophia Antipolis and CNRS, 06560 Valbonne, France. Unité Mixte de Recherche 144, Institut Curie and CNRS, F-75248 Paris, France
| | - Stefano Vanni
- Institut de Pharmacologie Moléculaire et Cellulaire, Université Nice Sophia Antipolis and CNRS, 06560 Valbonne, France
| | - Sophie Pagnotta
- Centre Commun de Microscopie Appliquée, Université Nice Sophia Antipolis, Parc Valrose, 06000 Nice, France
| | - Sandra Lacas-Gervais
- Centre Commun de Microscopie Appliquée, Université Nice Sophia Antipolis, Parc Valrose, 06000 Nice, France
| | - Laurie-Anne Payet
- Signalisation et Transports Ioniques Membranaires, Université de Poitiers and CNRS, Poitiers, France
| | - Thierry Ferreira
- Signalisation et Transports Ioniques Membranaires, Université de Poitiers and CNRS, Poitiers, France
| | - Romain Gautier
- Institut de Pharmacologie Moléculaire et Cellulaire, Université Nice Sophia Antipolis and CNRS, 06560 Valbonne, France
| | - Bruno Goud
- Unité Mixte de Recherche 144, Institut Curie and CNRS, F-75248 Paris, France
| | - Bruno Antonny
- Institut de Pharmacologie Moléculaire et Cellulaire, Université Nice Sophia Antipolis and CNRS, 06560 Valbonne, France.
| | - Hélène Barelli
- Institut de Pharmacologie Moléculaire et Cellulaire, Université Nice Sophia Antipolis and CNRS, 06560 Valbonne, France
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22
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Daumke O, Roux A, Haucke V. BAR domain scaffolds in dynamin-mediated membrane fission. Cell 2014; 156:882-92. [PMID: 24581490 DOI: 10.1016/j.cell.2014.02.017] [Citation(s) in RCA: 171] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2013] [Indexed: 10/25/2022]
Abstract
Biological membranes undergo constant remodeling by membrane fission and fusion to change their shape and to exchange material between subcellular compartments. During clathrin-mediated endocytosis, the dynamic assembly and disassembly of protein scaffolds comprising members of the bin-amphiphysin-rvs (BAR) domain protein superfamily constrain the membrane into distinct shapes as the pathway progresses toward fission by the GTPase dynamin. In this Review, we discuss how BAR domain protein assembly and disassembly are controlled in space and time and which structural and biochemical features allow the tight regulation of their shape and function to enable dynamin-mediated membrane fission.
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Affiliation(s)
- Oliver Daumke
- Max-Delbrück Centrum für Molekulare Medizin, Robert-Rössle-Strasse 10, 13125 Berlin, Germany; Institute of Chemistry and Biochemistry, Freie Universität Berlin, Takustraße 6, 14195 Berlin, Germany.
| | - Aurélien Roux
- University of Geneva, Department of Biochemistry, 30 quai Ernest Ansermet, 1211 Geneva 4, Switzerland, and Swiss National Centre for Competence in Research Programme Chemical Biology, 1211 Geneva, Switzerland.
| | - Volker Haucke
- Leibniz Institut für Molekulare Pharmakologie (FMP), Robert-Rössle-Strasse 10, 13125 Berlin, Germany; NeuroCure Cluster of Excellence, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany.
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23
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Kapus A, Janmey P. Plasma membrane--cortical cytoskeleton interactions: a cell biology approach with biophysical considerations. Compr Physiol 2013; 3:1231-81. [PMID: 23897686 DOI: 10.1002/cphy.c120015] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
From a biophysical standpoint, the interface between the cell membrane and the cytoskeleton is an intriguing site where a "two-dimensional fluid" interacts with an exceedingly complex three-dimensional protein meshwork. The membrane is a key regulator of the cytoskeleton, which not only provides docking sites for cytoskeletal elements through transmembrane proteins, lipid binding-based, and electrostatic interactions, but also serves as the source of the signaling events and molecules that control cytoskeletal organization and remolding. Conversely, the cytoskeleton is a key determinant of the biophysical and biochemical properties of the membrane, including its shape, tension, movement, composition, as well as the mobility, partitioning, and recycling of its constituents. From a cell biological standpoint, the membrane-cytoskeleton interplay underlies--as a central executor and/or regulator--a multitude of complex processes including chemical and mechanical signal transduction, motility/migration, endo-/exo-/phagocytosis, and other forms of membrane traffic, cell-cell, and cell-matrix adhesion. The aim of this article is to provide an overview of the tight structural and functional coupling between the membrane and the cytoskeleton. As biophysical approaches, both theoretical and experimental, proved to be instrumental for our understanding of the membrane/cytoskeleton interplay, this review will "oscillate" between the cell biological phenomena and the corresponding biophysical principles and considerations. After describing the types of connections between the membrane and the cytoskeleton, we will focus on a few key physical parameters and processes (force generation, curvature, tension, and surface charge) and will discuss how these contribute to a variety of fundamental cell biological functions.
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Affiliation(s)
- András Kapus
- Keenan Research Center, Li Ka Shing Knowledge Institute, St. Michael's Hospital and Department of Surgery, University of Toronto, Ontario, Canada.
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González-Jamett AM, Haro-Acuña V, Momboisse F, Caviedes P, Bevilacqua JA, Cárdenas AM. Dynamin-2 in nervous system disorders. J Neurochem 2013; 128:210-23. [DOI: 10.1111/jnc.12455] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 09/04/2013] [Accepted: 09/12/2013] [Indexed: 12/21/2022]
Affiliation(s)
- Arlek M. González-Jamett
- Centro Interdisciplinario de Neurociencia de Valparaíso; Facultad de Ciencias; Universidad de Valparaíso; Valparaíso Chile
| | - Valentina Haro-Acuña
- Centro Interdisciplinario de Neurociencia de Valparaíso; Facultad de Ciencias; Universidad de Valparaíso; Valparaíso Chile
| | - Fanny Momboisse
- Centro Interdisciplinario de Neurociencia de Valparaíso; Facultad de Ciencias; Universidad de Valparaíso; Valparaíso Chile
| | - Pablo Caviedes
- Programa de Farmacología Molecular y Clínica; Facultad de Medicina; Universidad de Chile; Santiago Chile
| | - Jorge A. Bevilacqua
- Departamento de Neurología y Neurocirugía; Hospital Clínico Universidad de Chile; and Programa de Anatomía y Biología del Desarrollo; ICBM; Facultad de Medicina; Universidad de Chile; Santiago Chile
| | - Ana M. Cárdenas
- Centro Interdisciplinario de Neurociencia de Valparaíso; Facultad de Ciencias; Universidad de Valparaíso; Valparaíso Chile
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25
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A local, periactive zone endocytic machinery at photoreceptor synapses in close vicinity to synaptic ribbons. J Neurosci 2013; 33:10278-300. [PMID: 23785143 DOI: 10.1523/jneurosci.5048-12.2013] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Photoreceptor ribbon synapses are continuously active synapses with large active zones that contain synaptic ribbons. Synaptic ribbons are anchored to the active zones and are associated with large numbers of synaptic vesicles. The base of the ribbon that is located close to L-type voltage-gated Ca(2+) channels is a hotspot of exocytosis. The continuous exocytosis at the ribbon synapse needs to be balanced by compensatory endocytosis. Recent analyses indicated that vesicle recycling at the synaptic ribbon is also an important determinant of synaptic signaling at the photoreceptor synapse. To get insights into mechanisms of vesicle recycling at the photoreceptor ribbon synapse, we performed super-resolution structured illumination microscopy and immunogold electron microscopy to localize major components of the endocytotic membrane retrieval machinery in the photoreceptor synapse of the mouse retina. We found dynamin, syndapin, amphiphysin, and calcineurin, a regulator of activity-dependent endocytosis, to be highly enriched around the active zone and the synaptic ribbon. We present evidence for two clathrin heavy chain variants in the photoreceptor terminal; one is enriched around the synaptic ribbon, whereas the other is localized in the entry region of the terminal. The focal enrichment of endocytic proteins around the synaptic ribbon is consistent with a focal uptake of endocytic markers at that site. This endocytic activity functionally depends on dynamin. These data propose that the presynaptic periactive zone surrounding the synaptic ribbon complex is a hotspot of endocytosis in photoreceptor ribbon synapses.
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26
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Neumann S, Schmid SL. Dual role of BAR domain-containing proteins in regulating vesicle release catalyzed by the GTPase, dynamin-2. J Biol Chem 2013; 288:25119-25128. [PMID: 23861397 DOI: 10.1074/jbc.m113.490474] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Dynamin-2 (Dyn2) is ubiquitously expressed and catalyzes membrane fission during clathrin-mediated endocytosis in nonneuronal cells. We have previously shown that Dyn2 inefficiently generates membrane curvature and only mediates fission of highly curved membranes. This led to the hypothesis that other endocytic accessory proteins (EAPs) generate curvature needed to sculpt a sufficiently narrow neck to trigger Dyn2 assembly and fission. Candidates for this activity are EAPs that bind to the dynamin proline/arginine-rich domain (PRD) through their SH3 (src homology-3) domains and also encode curvature-generating BAR (Bin/Amphiphysin/Rvs) domains. We show that at low concentrations, amphiphysin and endophilin, but not SNX9 or the curvature-generating epsin N-terminal homology (ENTH) domain, are able to generate tubules from planar membrane templates and to synergize with Dyn2ΔPRD to catalyze vesicle release. Unexpectedly, SH3-PRD interactions were inhibitory and reciprocally regulate scaffold assembly. Of the three proteins studied, only full-length amphiphysin functions synergistically with full-length Dyn2 to catalyze vesicle release. The differential activity of these proteins correlates with the relative potency of their positive, curvature-generating activity, and the negative regulatory effects mediated by SH3 domain interactions. Our findings reveal opportunities for the spatio-temporal coordination of membrane curvature generation, dynamin assembly, and fission during clathrin-mediated endocytosis.
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Affiliation(s)
- Sylvia Neumann
- From the Department of Cell Biology, The Scripps Research Institute, La Jolla, California 92037
| | - Sandra L Schmid
- From the Department of Cell Biology, The Scripps Research Institute, La Jolla, California 92037.
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Popova N, Deyev I, Petrenko A. Clathrin-mediated endocytosis and adaptor proteins. Acta Naturae 2013; 5:62-73. [PMID: 24307937 PMCID: PMC3848845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Macromolecules gain access to the cytoplasm of eukaryotic cells using one of several ways of which clathrin-dependent endocytosis is the most researched. Although the mechanism of clathrin-mediated endocytosis is well understood in general, novel adaptor proteins that play various roles in ensuring specific regulation of the mentioned process are being discovered all the time. This review provides a detailed account of the mechanism of clathrin-mediated internalization of activated G protein-coupled receptors, as well as a description of the major proteins involved in this process.
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Affiliation(s)
- N.V. Popova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Miklukho-Maklaya St., 16/10, Moscow, Russia, 117997
| | - I.E. Deyev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Miklukho-Maklaya St., 16/10, Moscow, Russia, 117997
| | - A.G. Petrenko
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Miklukho-Maklaya St., 16/10, Moscow, Russia, 117997
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Stabilization of actin bundles by a dynamin 1/cortactin ring complex is necessary for growth cone filopodia. J Neurosci 2013; 33:4514-26. [PMID: 23467367 DOI: 10.1523/jneurosci.2762-12.2013] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Dynamin GTPase, a key molecule in endocytosis, mechanically severs the invaginated membrane upon GTP hydrolysis. Dynamin functions also in regulating actin cytoskeleton, but the mechanisms are yet to be defined. Here we show that dynamin 1, a neuronal isoform of dynamin, and cortactin form ring complexes, which twine around F-actin bundles and stabilize them. By negative-staining EM, dynamin 1-cortactin complexes appeared as "open" or "closed" rings depending on guanine nucleotide conditions. By pyrene actin assembly assay, dynamin 1 stimulated actin assembly in mouse brain cytosol. In vitro incubation of F-actin with both dynamin 1 and cortactin led to the formation of long and thick actin bundles, on which dynamin 1 and cortactin were periodically colocalized in puncta. A depolymerization assay revealed that dynamin 1 and cortactin increased the stability of actin bundles, most prominently in the presence of GTP. In rat cortical neurons and human neuroblastoma cell line, SH-SY5Y, both dynamin 1 and cortactin localized on actin filaments and the bundles at growth cone filopodia as revealed by immunoelectron microscopy. In SH-SY5Y cell, acute inhibition of dynamin 1 by application of dynamin inhibitor led to growth cone collapse. Cortactin knockdown also reduced growth cone filopodia. Together, our results strongly suggest that dynamin 1 and cortactin ring complex mechanically stabilizes F-actin bundles in growth cone filopodia. Thus, the GTPase-dependent mechanochemical enzyme property of dynamin is commonly used both in endocytosis and regulation of F-actin bundles by a dynamin 1-cortactin complex.
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Meinecke M, Boucrot E, Camdere G, Hon WC, Mittal R, McMahon HT. Cooperative recruitment of dynamin and BIN/amphiphysin/Rvs (BAR) domain-containing proteins leads to GTP-dependent membrane scission. J Biol Chem 2013; 288:6651-61. [PMID: 23297414 PMCID: PMC3585104 DOI: 10.1074/jbc.m112.444869] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Dynamin mediates various membrane fission events, including the scission of clathrin-coated vesicles. Here, we provide direct evidence for cooperative membrane recruitment of dynamin with the BIN/amphiphysin/Rvs (BAR) proteins, endophilin and amphiphysin. Surprisingly, endophilin and amphiphysin recruitment to membranes was also dependent on binding to dynamin due to auto-inhibition of BAR-membrane interactions. Consistent with reciprocal recruitment in vitro, dynamin recruitment to the plasma membrane in cells was strongly reduced by concomitant depletion of endophilin and amphiphysin, and conversely, depletion of dynamin dramatically reduced the recruitment of endophilin. In addition, amphiphysin depletion was observed to severely inhibit clathrin-mediated endocytosis. Furthermore, GTP-dependent membrane scission by dynamin was dramatically elevated by BAR domain proteins. Thus, BAR domain proteins and dynamin act in synergy in membrane recruitment and GTP-dependent vesicle scission.
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Affiliation(s)
- Michael Meinecke
- Laboratory of Molecular Biology, Medical Research Council, Hills Road, Cambridge CB2 0QH, United Kingdom
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Mattiazzi M, Sun Y, Wolinski H, Bavdek A, Petan T, Anderluh G, Kohlwein SD, Drubin DG, Križaj I, Petrovič U. A neurotoxic phospholipase A2 impairs yeast amphiphysin activity and reduces endocytosis. PLoS One 2012; 7:e40931. [PMID: 22844417 PMCID: PMC3402474 DOI: 10.1371/journal.pone.0040931] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Accepted: 06/15/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Presynaptically neurotoxic phospholipases A(2) inhibit synaptic vesicle recycling through endocytosis. PRINCIPAL FINDINGS Here we provide insight into the action of a presynaptically neurotoxic phospholipase A(2) ammodytoxin A (AtxA) on clathrin-dependent endocytosis in budding yeast. AtxA caused changes in the dynamics of vesicle formation and scission from the plasma membrane in a phospholipase activity dependent manner. Our data, based on synthetic dosage lethality screen and the analysis of the dynamics of sites of endocytosis, indicate that AtxA impairs the activity of amphiphysin. CONCLUSIONS We identified amphiphysin and endocytosis as the target of AtxA intracellular activity. We propose that AtxA reduces endocytosis following a mechanism of action which includes both a specific protein-protein interaction and enzymatic activity, and which is applicable to yeast and mammalian cells. Knowing how neurotoxic phospholipases A(2) work can open new ways to regulate endocytosis.
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Affiliation(s)
- Mojca Mattiazzi
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Yidi Sun
- Department of Molecular and Cell Biology, University of California, Berkeley, California, United States of America
| | - Heimo Wolinski
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Andrej Bavdek
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Toni Petan
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Gregor Anderluh
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Sepp D. Kohlwein
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - David G. Drubin
- Department of Molecular and Cell Biology, University of California, Berkeley, California, United States of America
| | - Igor Križaj
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Uroš Petrovič
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia
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Tian Q, Zhang JF, Fan J, Song Z, Chen Y. Endophilin isoforms have distinct characteristics in interactions with N-type Ca2+ channels and dynamin I. Neurosci Bull 2012; 28:483-92. [PMID: 22961472 DOI: 10.1007/s12264-012-1257-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Accepted: 05/10/2012] [Indexed: 11/28/2022] Open
Abstract
OBJECTIVE Formation of the endophilin II-Ca(2+) channel complex is Ca(2+)-dependent in clathrin-mediated endocytosis. However, little is known about whether the other two endophilin isoforms have the same features. The present study aimed to investigate the characteristics of the interactions of all three isoforms with Ca(2+) channels and dynamin I. METHODS N-type Ca(2+) channel C-terminal fragments (NCFs) synthesized with a (3)H-leucine-labeled kit, were incubated with endophilin-GST fusion proteins, followed by pull-down assay. Results were counted on a scintillation counter. In addition, the different endophilin isoforms were each co-transfected with dynamin I into 293T cells, followed by flow cytometry and co-immunoprecipitation assay. Immunostaining was performed and an image analysis program was used to evaluate the overlap coefficient of cells expressing endophilin and dynamin I. RESULTS All three isoforms interacted with NCF. Endophilins I and II demonstrated clear Ca(2+)-dependent interactions with NCF, whereas endophilin III did not. Co-immunoprecipitation showed that, compared to endophilin I/II, the interaction between endophilin III and dynamin I was significantly increased. Similar results were obtained from flow cytometry. Furthermore, endophilin III had a higher overlap coefficient with dynamin I in co-transfected 293T cells. CONCLUSION Endophilin isoforms have distinct characteristics in interactions with NCF and dynamin I. Endophilin III binding to NCF is Ca(2+)-independent, implying that it plays a different role in clathrin-mediated endocytosis.
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Affiliation(s)
- Qi Tian
- Center for Neurobiology, Zhongshan School of Medicine, Guangzhou, 510080, China
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32
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Troulinaki K, Tavernarakis N. Endocytosis and intracellular trafficking contribute to necrotic neurodegeneration in C. elegans. EMBO J 2011; 31:654-66. [PMID: 22157748 DOI: 10.1038/emboj.2011.447] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Accepted: 11/09/2011] [Indexed: 11/09/2022] Open
Abstract
Unlike apoptosis, necrotic cell death is characterized by marked loss of plasma membrane integrity. Leakage of cytoplasmic material to the extracellular space contributes to cell demise, and is the cause of acute inflammatory responses, which typically accompany necrosis. The mechanisms underlying plasma membrane damage during necrotic cell death are not well understood. We report that endocytosis is critically required for the execution of necrosis. Depletion of the key endocytic machinery components dynamin, synaptotagmin and endophilin suppresses necrotic neurodegeneration induced by diverse genetic and environmental insults in C. elegans. We used genetically encoded fluorescent markers to monitor the formation and fate of specific types of endosomes during cell death in vivo. Strikingly, we find that the number of early and recycling endosomes increases sharply and transiently upon initiation of necrosis. Endosomes subsequently coalesce around the nucleus and disintegrate during the final stage of necrosis. Interfering with kinesin-mediated endosome trafficking impedes cell death. Endocytosis synergizes with autophagy and lysosomal proteolytic mechanisms to facilitate necrotic neurodegeneration. These findings demonstrate a prominent role for endocytosis in cellular destruction during neurodegeneration, which is likely conserved in metazoans.
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Affiliation(s)
- Kostoula Troulinaki
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, Heraklion, Greece
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33
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Thomas RS, Lelos MJ, Good MA, Kidd EJ. Clathrin-mediated endocytic proteins are upregulated in the cortex of the Tg2576 mouse model of Alzheimer's disease-like amyloid pathology. Biochem Biophys Res Commun 2011; 415:656-61. [PMID: 22079091 DOI: 10.1016/j.bbrc.2011.10.131] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Accepted: 10/28/2011] [Indexed: 10/15/2022]
Abstract
Amyloid-β (Aβ) is cleaved from amyloid precursor protein (APP) predominantly after APP has trafficked through the secretory pathway and then become re-internalised by endocytosis. Clathrin-mediated and, more recently, clathrin-independent endocytosis have both been implicated in this process. Furthermore, endocytic abnormalities have been identified in cases of Alzheimer's disease (AD), however, the relevance of these changes to the aetiology of the disease remains unclear. We therefore examined the expression of proteins related to these endocytic processes in the cortex of Tg2576 mice that overexpress the Swedish mutation in APP, and consequently overexpress Aβ, to determine if there were any changes in their associated pathways. We identified significant increases in the levels of clathrin, dynamin and PICALM, all proteins intimately involved with the clathrin-mediated endocytic pathway, in the transgenic animals. However, levels of proteins associated with flotillin or caveolin-mediated endocytic pathways remained unchanged. These results emphasise the importance of clathrin-mediated endocytosis in the aetiology of AD and reinforce the results of the recent GWAS studies that identified genes for clathrin-mediated endocytosis as susceptibility genes for AD. Such studies in transgenic mice will allow us to learn more about the role of clathrin-mediated endocytosis in AD.
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Affiliation(s)
- Rhian S Thomas
- Welsh School of Pharmacy, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff CF10 3NB, UK.
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34
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Knezevic I, Predescu D, Bardita C, Wang M, Sharma T, Keith B, Neamu R, Malik AB, Predescu S. Regulation of dynamin-2 assembly-disassembly and function through the SH3A domain of intersectin-1s. J Cell Mol Med 2011; 15:2364-76. [PMID: 21129155 PMCID: PMC3072443 DOI: 10.1111/j.1582-4934.2010.01226.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Accepted: 11/18/2010] [Indexed: 01/05/2023] Open
Abstract
Intersectin-1s (ITSN-1s), a five Src homology 3 (SH3) domain-containing protein, is critically required for caveolae and clathrin-mediated endocytosis (CME), due to its interactions with dynamin (dyn). Of the five SH3A-E domains, SH3A is unique because of its high affinity for dyn and potent inhibition of CME. However, the molecular mechanism by which SH3A integrates in the overall function of ITSN-1s to regulate the endocytic process is not understood. Using biochemical and functional approaches as well as high-resolution electron microscopy, we show that SH3A exogenously expressed in human lung endothelial cells caused abnormal endocytic structures, distorted caveolae clusters, frequent staining-dense rings around the caveolar necks and 60% inhibition of caveolae internalization. In vitro studies further revealed that SH3A, similar to full-length ITSN-1s stimulates dyn2 oligomerization and guanosine triphosphatase (GTP)ase activity, effects not detected when other SH3 domains of ITSN-1s were used as controls. Strikingly, in the presence of SH3A, dyn2-dyn2 interactions are stabilized and despite continuous GTP hydrolysis, dyn2 oligomers cannot disassemble. SH3A may hold up caveolae release from the plasma membrane and formation of free-transport vesicles, by prolonging the lifetime of assembled dyn2. Altogether, our results indicate that ITSN-1s, via its SH3A has the unique ability to regulate dyn2 assembly-disassembly and function during endocytosis.
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Affiliation(s)
- Ivana Knezevic
- Department of Pharmacology, Rush University Medical Center, Medical College, Vascular Biology SectionChicago, IL, USA
| | - Dan Predescu
- Department of Pharmacology, Rush University Medical Center, Medical College, Vascular Biology SectionChicago, IL, USA
| | - Cristina Bardita
- Department of Pharmacology, Rush University Medical Center, Medical College, Vascular Biology SectionChicago, IL, USA
| | - Minhua Wang
- Department of Pharmacology, Rush University Medical Center, Medical College, Vascular Biology SectionChicago, IL, USA
| | - Tiffany Sharma
- Department of Pharmacology, University of Illinois at Chicago, College of MedicineChicago, IL, USA
| | - Barbara Keith
- Department of Pharmacology, University of Illinois at Chicago, College of MedicineChicago, IL, USA
| | - Radu Neamu
- Saint Raphael HospitalNew Haven, CT, USA
| | - Asrar B Malik
- Department of Pharmacology, University of Illinois at Chicago, College of MedicineChicago, IL, USA
| | - Sanda Predescu
- Department of Pharmacology, Rush University Medical Center, Medical College, Vascular Biology SectionChicago, IL, USA
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Abstract
Bacteria and eukaryotic cells contain geometry-sensing tools in their cytosol: protein motifs or domains that recognize the curvature, concave or convex, deep or shallow, of lipid membranes. These sensors contrast with classical lipid-binding domains by their extended structure and, sometimes, counterintuitive chemistry. Among the sensors are long amphipathic helices, such as the ALPS motif and the N-terminal region of α-synuclein, whose apparent "design defects" translate into a remarkable ability to specifically adsorb to the surface of small vesicles. Fundamental differences in the lipid composition of membranes of the early and late secretory pathways probably explain why some sensors use mostly electrostatics whereas others take advantage of the hydrophobic effect. Membrane curvature sensors help to organize very diverse reactions, such as lipid transfer between membranes, the tethering of vesicles at the Golgi apparatus, and the assembly-disassembly cycle of protein coats.
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Affiliation(s)
- Bruno Antonny
- Université de Nice-Sophia Antipolis and Centre National de la Recheche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, 06560 Valbonne, France.
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Koch J, Brocard C. Membrane elongation factors in organelle maintenance: the case of peroxisome proliferation. Biomol Concepts 2011; 2:353-364. [PMID: 21984887 DOI: 10.1515/bmc.2011.031] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Separation of metabolic pathways in organelles is critical for eukaryotic life. Accordingly, the number, morphology and function of organelles have to be maintained through processes linked with membrane remodeling events. Despite their acknowledged significance and intense study many questions remain about the molecular mechanisms by which organellar membranes proliferate. Here, using the example of peroxisome proliferation, we give an overview of how proteins elongate membranes. Subsequent membrane fission is achieved by dynamin-related proteins shared with mitochondria. We discuss basic criteria that membranes have to fulfill for these fission factors to complete the scission. Because peroxisome elongation is always associated with unequal distribution of matrix and membrane proteins, we propose peroxisomal division to be non-stochastic and asymmetric. We further show that these organelles need not be functional to carry on membrane elongation and present the most recent findings concerning members of the Pex11 protein family as membrane elongation factors. These factors, beside known proteins such as BAR-domain proteins, represent another family of proteins containing an amphipathic α-helix with membrane bending activity.
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Affiliation(s)
- Johannes Koch
- Department of Biochemistry and Cell Biology, University of Vienna, Max F. Perutz Laboratories, Center of Molecular Biology, Dr. Bohr-Gasse 9, A-1030 Vienna, Austria
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Qualmann B, Koch D, Kessels MM. Let's go bananas: revisiting the endocytic BAR code. EMBO J 2011; 30:3501-15. [PMID: 21878992 DOI: 10.1038/emboj.2011.266] [Citation(s) in RCA: 194] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 07/15/2011] [Indexed: 12/27/2022] Open
Abstract
Against the odds of membrane resistance, members of the BIN/Amphiphysin/Rvs (BAR) domain superfamily shape membranes and their activity is indispensable for a plethora of life functions. While crystal structures of different BAR dimers advanced our understanding of membrane shaping by scaffolding and hydrophobic insertion mechanisms considerably, especially life-imaging techniques and loss-of-function studies of clathrin-mediated endocytosis with its gradually increasing curvature show that the initial idea that solely BAR domain curvatures determine their functions is oversimplified. Diagonal placing, lateral lipid-binding modes, additional lipid-binding modules, tilde shapes and formation of macromolecular lattices with different modes of organisation and arrangement increase versatility. A picture emerges, in which BAR domain proteins create macromolecular platforms, that recruit and connect different binding partners and ensure the connection and coordination of the different events during the endocytic process, such as membrane invagination, coat formation, actin nucleation, vesicle size control, fission, detachment and uncoating, in time and space, and may thereby offer mechanistic explanations for how coordination, directionality and effectiveness of a complex process with several steps and key players can be achieved.
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Affiliation(s)
- Britta Qualmann
- Institute for Biochemistry I, University Hospital Jena-Friedrich Schiller University Jena, Germany.
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38
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Ramanan V, Agrawal NJ, Liu J, Engles S, Toy R, Radhakrishnan R. Systems biology and physical biology of clathrin-mediated endocytosis. Integr Biol (Camb) 2011; 3:803-15. [PMID: 21792431 PMCID: PMC3153420 DOI: 10.1039/c1ib00036e] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
In this review, we describe the application of experimental data and modeling of intracellular endocytic trafficking mechanisms with a focus on the process of clathrin-mediated endocytosis. A detailed parts-list for the protein-protein interactions in clathrin-mediated endocytosis has been available for some time. However, recent experimental, theoretical, and computational tools have proved to be critical in establishing a sequence of events, cooperative dynamics, and energetics of the intracellular process. On the experimental front, total internal reflection fluorescence microscopy, photo-activated localization microscopy, and spinning-disk confocal microscopy have focused on assembly and patterning of endocytic proteins at the membrane, while on the theory front, minimal theoretical models for clathrin nucleation, biophysical models for membrane curvature and bending elasticity, as well as methods from computational structural and systems biology, have proved insightful in describing membrane topologies, curvature mechanisms, and energetics.
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Affiliation(s)
- Vyas Ramanan
- Department of Bioengineering, University of Pennsylvania, 210 South 33rd Street, Philadelphia, PA 19104, USA
| | - Neeraj J. Agrawal
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, 210 South 33rd Street, Philadelphia, PA 19104, USA
| | - Jin Liu
- Department of Bioengineering, University of Pennsylvania, 210 South 33rd Street, Philadelphia, PA 19104, USA
| | - Sean Engles
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, 210 South 33rd Street, Philadelphia, PA 19104, USA
| | - Randall Toy
- Department of Bioengineering, University of Pennsylvania, 210 South 33rd Street, Philadelphia, PA 19104, USA
| | - Ravi Radhakrishnan
- Department of Bioengineering, University of Pennsylvania, 210 South 33rd Street, Philadelphia, PA 19104, USA
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, 210 South 33rd Street, Philadelphia, PA 19104, USA
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39
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Abstract
Receptor-mediated endocytosis is used by a number of viruses and toxins to gain entry into cells. Some have evolved to use specific lipids in the plasma membrane as their receptors. They include bacterial toxins such as Shiga and Cholera toxin and viruses such as mouse polyoma virus and simian virus 40. Through multivalent binding to glycosphingolipids, they induce lipid clustering and changes in membrane properties. Internalization occurs by unusual endocytic mechanisms involving lipid rafts, induction of membrane curvature, trans-bilayer coupling, and activation of signaling pathways. Once delivered to early endosomes, they follow diverse intracellular routes to the lumen of the ER, from which they penetrate into the cytosol. The role of the lipid receptors is central in these well-studied processes.
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Affiliation(s)
- Helge Ewers
- Laboratorium für Physikalische Chemie, ETH Zurich, 8093 Zurich, Switzerland
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40
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Differential curvature sensing and generating activities of dynamin isoforms provide opportunities for tissue-specific regulation. Proc Natl Acad Sci U S A 2011; 108:E234-42. [PMID: 21670293 DOI: 10.1073/pnas.1102710108] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Dynamin 1 (Dyn1) and Dyn2 are neuronal and ubiquitously expressed isoforms, respectively, of the multidomain GTPase required for clathrin-mediated endocytosis (CME). Although they are 79% identical, Dyn1 and Dyn2 are not fully functionally redundant. Through direct measurements of basal and assembly-stimulated GTPase activities, membrane binding, self-assembly, and membrane fission on planar and curved templates, we have shown that Dyn1 is an efficient curvature generator, whereas Dyn2 is primarily a curvature sensor. Using Dyn1/Dyn2 chimeras, we identified the lipid-binding pleckstrin homology domain as being responsible for the differential in vitro properties of these two isoforms. Remarkably, their in vitro activities were reversed by a single amino acid change in the membrane-binding variable loop 3. Reconstitution of KO mouse embryo fibroblasts showed that both the pleckstrin homology and the Pro/Arg-rich domains determine the differential abilities of these two isoforms to support CME. These domains are specific to classical dynamins and are involved in regulating their activity. Our findings reveal opportunities for fundamental differences in the regulation of Dyn1, which mediates rapid endocytosis at the synapse, vs. Dyn2, which regulates early and late events in CME in nonneuronal cells.
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41
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Abstract
We review mainly the work from our research group here. Our focus has been on the use of genetic methods to delineate the mechanisms of synaptic vesicle recycling and cellular trafficking. Acute temperature-sensitive paralytic mutants have been of particular value in this approach. We have primarily used screens for suppressor and enhancer mutations to identify genetic loci coding for proteins that interact with Dynamin in Drosophila. In addition, we have used reverse genetic approaches to investigate few other candidate molecules that may play a role in synaptic vesicle endocytosis. We have in particular discussed at some length the role of endocytic accessory proteins Stoned and Eps15 in vesicle recycling.
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Affiliation(s)
- Riddhi Majumder
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
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42
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Ross JA, Chen Y, Müller J, Barylko B, Wang L, Banks HB, Albanesi JP, Jameson DM. Dimeric endophilin A2 stimulates assembly and GTPase activity of dynamin 2. Biophys J 2011; 100:729-737. [PMID: 21281588 DOI: 10.1016/j.bpj.2010.12.3717] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Revised: 12/02/2010] [Accepted: 12/14/2010] [Indexed: 10/18/2022] Open
Abstract
Endophilin, which participates in membrane vesiculation during receptor-mediated endocytosis, is a ∼40 kDa SH3 domain-containing protein that binds to the proline/arginine-rich domain of dynamin, a ∼100 kDa GTPase that is essential for endocytic membrane scission. It has been suggested that endophilin is monomeric in the cytoplasm and dimerizes only after it binds to membranes (or perhaps to dimers or tetramers of dynamin). To clarify this issue, we studied the oligomeric state of endophilin both in vitro using analytical ultracentrifugation and fluorescence anisotropy, and in living cells using two-photon fluorescence fluctuation spectroscopy. We analyzed the fluctuation data using the Q-analysis method, which allowed us to determine the intrinsic brightness of the labeled protein complexes and hence its aggregation state in the cytoplasmic regions of the cell. Although a relatively high K(d) (∼5-15 μM) was observed in vitro, the cell measurements indicate that endophilin is dimeric in the cytoplasm, even at submicromolar concentrations. We also demonstrate that endophilin significantly enhances the assembly of dynamin, and that this enhancement is proportional to the fraction of dimeric endophilin that is present. Moreover, there is correlation between the concentrations of endophilin that promote dynamin self-assembly and those that stimulate dynamin GTPase activity. These findings support the view that endophilin-dynamin interactions play an important role in endocytosis.
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Affiliation(s)
- Justin A Ross
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
| | - Yan Chen
- Physics Department, University of Minnesota, Minneapolis, Minnesota
| | - Joachim Müller
- Physics Department, University of Minnesota, Minneapolis, Minnesota
| | - Barbara Barylko
- Pharmacology Department, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Lei Wang
- Pharmacology Department, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Hunter B Banks
- Pharmacology Department, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Joseph P Albanesi
- Pharmacology Department, University of Texas Southwestern Medical Center, Dallas, Texas
| | - David M Jameson
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii.
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43
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Abstract
During exocytosis, neuroendocrine cells can achieve partial release of stored secretory products from dense core vesicles (DCVs) by coupling endocytosis directly at fusion sites and without full discharge. The physiological role of partial secretion is of substantial interest. Much is known about SNARE-mediated initiation of exocytosis and dynamin-mediated completion of endocytosis, but little is known about coupling events. We have used real-time microscopy to examine the role of secretory carrier membrane protein SCAMP1 in exo-endocytic coupling in PC12 cells. While reduced SCAMP1 expression is known to impede dilation of newly opened fusion pores during onset of DCV exocytosis, we now show that SCAMP1 deficiency also inhibits closure of fusion pores after they have opened. Inhibition causes accumulation of fusion figures at the plasma membrane. Closure is recovered by restoring expression and accelerated slightly by overexpression. Interestingly, inhibited pore closure resulting from loss of SCAMP1 appears to increase secondary fusion of DCVs to already-fused DCVs (compound exocytosis). Unexpectedly, reinternalization of expanded DCV membranes following compound exocytosis appears to proceed normally in SCAMP1-deficient cells. SCAMP1's apparent dual role in facilitating dilation and closure of fusion pores implicates its function in exo-endocytic coupling and in the regulation of partial secretion. Secondarily, SCAMP1 may serve to limit the extent of compound exocytosis.
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Affiliation(s)
- Jie Zhang
- Department of Cell Biology, Molecular, Cell and Developmental Biology Program, University of Virginia, Charlottesville, VA 22908-0732, USA.
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44
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Low HH, Löwe J. Dynamin architecture--from monomer to polymer. Curr Opin Struct Biol 2010; 20:791-8. [PMID: 20970992 DOI: 10.1016/j.sbi.2010.09.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2010] [Revised: 09/09/2010] [Accepted: 09/15/2010] [Indexed: 01/04/2023]
Abstract
Dynamins form a family of eukaryotic and prokaryotic proteins involved in membrane fission, fusion and restructuring. They have complex mechanisms of self-assembly, which are coupled to the tubulation and destabilization of lipid bilayers. Recent structural data has revolutionized our understanding and is now yielding detailed insights into dynamin structure, from monomer through to polymer. Traditional division of the dynamin subunit into GTPase domain, middle domain and GTPase effector domain based on sequence alignments and biochemistry is not supported by recent structural data. A unified model of dynamin architecture is presented here, based on observation that the basic dynamin fold is conserved across evolutionary kingdoms.
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Affiliation(s)
- Harry H Low
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, United Kingdom.
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45
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Arumugam S, Chwastek G, Schwille P. Protein-membrane interactions: the virtue of minimal systems in systems biology. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2010; 3:269-80. [PMID: 20865776 DOI: 10.1002/wsbm.119] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The plasma membrane of cells can be viewed as a highly dynamic, regulated, heterogeneous environment with multiple functions. It constitutes the boundary of the cell, encapsulating all its components. Proteins interact with the membrane in many ways to accommodate essential processes, such as membrane trafficking, membrane protrusions, cytokinesis, signaling, and cell-cell communication. A vast amount of literature has already fostered our current understanding of membrane-protein interactions. However, many phenomena still remain to be understood, e.g., the exact mechanisms of how certain proteins cause or assist membrane transformations. Systems biology aims to predict biological processes on the basis of the set of molecules involved. Many key processes arise from interactions with the lipid membrane. Protein interactome maps do not consider such specific interactions, and thus cannot predict precise outcomes of the interactions of the involved proteins. These can only be inferred from experimental approaches. We describe examples of how an emergent behavior of protein-membrane interactions has been demonstrated by the use of minimal systems. These studies contribute to a deeper understanding of protein interactomes involving membranes and complement other approaches of systems biology.
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46
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Kenniston JA, Lemmon MA. Dynamin GTPase regulation is altered by PH domain mutations found in centronuclear myopathy patients. EMBO J 2010; 29:3054-67. [PMID: 20700106 PMCID: PMC2944063 DOI: 10.1038/emboj.2010.187] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Accepted: 07/14/2010] [Indexed: 01/18/2023] Open
Abstract
The large GTPase dynamin has an important membrane scission function in receptor-mediated endocytosis and other cellular processes. Self-assembly on phosphoinositide-containing membranes stimulates dynamin GTPase activity, which is crucial for its function. Although the pleckstrin-homology (PH) domain is known to mediate phosphoinositide binding by dynamin, it remains unclear how this promotes activation. Here, we describe studies of dynamin PH domain mutations found in centronuclear myopathy (CNM) that increase dynamin's GTPase activity without altering phosphoinositide binding. CNM mutations in the PH domain C-terminal α-helix appear to cause conformational changes in dynamin that alter control of the GTP hydrolysis cycle. These mutations either 'sensitize' dynamin to lipid stimulation or elevate basal GTPase rates by promoting self-assembly and thus rendering dynamin no longer lipid responsive. We also describe a low-resolution structure of dimeric dynamin from small-angle X-ray scattering that reveals conformational changes induced by CNM mutations, and defines requirements for domain rearrangement upon dynamin self-assembly at membrane surfaces. Our data suggest that changes in the PH domain may couple lipid binding to dynamin GTPase activation at sites of vesicle invagination.
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Affiliation(s)
- Jon A Kenniston
- Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Mark A Lemmon
- Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
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47
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Ramachandran R. Vesicle scission: dynamin. Semin Cell Dev Biol 2010; 22:10-7. [PMID: 20837154 DOI: 10.1016/j.semcdb.2010.09.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Revised: 09/03/2010] [Accepted: 09/03/2010] [Indexed: 11/17/2022]
Abstract
Dynamin is a large GTPase involved in endocytic vesicle formation, but its exact role and mechanism are subjects of long-standing debate. Despite recent advances in the structural analyses of isolated dynamin domains and the faithful reconstitution of dynamin-dependent membrane fission in model membrane systems, the mechanism of its action remains poorly understood at the molecular level. Here, I will review current progress in elucidating dynamin action in vesicle scission and highlight the most visible gaps in knowledge that limit the development of a coherent and complete model for its role in vesicle biogenesis. Coordinated functions of BAR domain-containing binding partners are also discussed.
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Affiliation(s)
- Rajesh Ramachandran
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
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48
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Dores MR, Schnell JD, Maldonado-Baez L, Wendland B, Hicke L. The function of yeast epsin and Ede1 ubiquitin-binding domains during receptor internalization. Traffic 2010; 11:151-60. [PMID: 19903324 DOI: 10.1111/j.1600-0854.2009.01003.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The formation of a primary endocytic vesicle is a dynamic process involving the transient organization of adaptor and scaffold proteins at the plasma membrane. Epsins and Eps15-like proteins are ubiquitin-binding proteins that act early in this process. The yeast epsins, Ent1 and Ent2, carry functional ubiquitin-interacting motifs (UIMs), whereas the yeast Eps15-like protein, Ede1, has a C-terminal ubiquitin-associated (UBA) domain. Analysis of mutants lacking early endocytic adaptors reveals that the ubiquitin-binding domains (UBDs) of Ent2 and Ede1 are likely to function primarily to mediate protein-protein interactions between components of the early endocytic machinery. Cells that lack epsin and Ede1 UBDs are able to internalize activated, ubiquitinated receptors. Furthermore, under conditions in which epsin UIMs are important for receptor internalization, receptors internalized via both ubiquitin-dependent and ubiquitin-independent signals require the UIMs, indicating that UIM function is not restricted to ubiquitinated receptors. Epsin UIMs share function with non-UBD protein-protein interaction motifs in Ent2 and Ede1, and the Ede1 UBA domain appears to negatively regulate interactions between endocytic proteins. Together, our results suggest that the ubiquitin-binding domains within the yeast epsin Ent2 and Ede1 are involved in the formation and regulation of the endocytic network.
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Affiliation(s)
- Michael R Dores
- Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, 2205 Campus Drive, Evanston, IL 60208, USA
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49
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Molecular basis for SH3 domain regulation of F-BAR-mediated membrane deformation. Proc Natl Acad Sci U S A 2010; 107:8213-8. [PMID: 20404169 DOI: 10.1073/pnas.1003478107] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Members of the Bin/amphiphysin/Rvs (BAR) domain protein superfamily are involved in membrane remodeling in various cellular pathways ranging from endocytic vesicle and T-tubule formation to cell migration and neuromorphogenesis. Membrane curvature induction and stabilization are encoded within the BAR or Fer-CIP4 homology-BAR (F-BAR) domains, alpha-helical coiled coils that dimerize into membrane-binding modules. BAR/F-BAR domain proteins often contain an SH3 domain, which recruits binding partners such as the oligomeric membrane-fissioning GTPase dynamin. How precisely BAR/F-BAR domain-mediated membrane deformation is regulated at the cellular level is unknown. Here we present the crystal structures of full-length syndapin 1 and its F-BAR domain. Our data show that syndapin 1 F-BAR-mediated membrane deformation is subject to autoinhibition by its SH3 domain. Release from the clamped conformation is driven by association of syndapin 1 SH3 with the proline-rich domain of dynamin 1, thereby unlocking its potent membrane-bending activity. We hypothesize that this mechanism might be commonly used to regulate BAR/F-BAR domain-induced membrane deformation and to potentially couple this process to dynamin-mediated fission. Our data thus suggest a structure-based model for SH3-mediated regulation of BAR/F-BAR domain function.
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50
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Ayton GS, Lyman E, Voth GA. Hierarchical coarse-graining strategy for protein-membrane systems to access mesoscopic scales. Faraday Discuss 2010; 144:347-57; discussion 445-81. [PMID: 20158037 DOI: 10.1039/b901996k] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
An overall multiscale simulation strategy for large scale coarse-grain simulations of membrane protein systems is presented. The protein is modeled as a heterogeneous elastic network, while the lipids are modeled using the hybrid analytic-systematic (HAS) methodology, where in both cases atomistic level information obtained from molecular dynamics simulation is used to parameterize the model. A feature of this approach is that from the outset liposome length scales are employed in the simulation (i.e., on the order of 1/2 a million lipids plus protein). A route to develop highly coarse-grained models from molecular-scale information is proposed and results for N-BAR domain protein remodeling of a liposome are presented.
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Affiliation(s)
- Gary S Ayton
- Center for Biophysical Modeling and Simulation and Department of Chemistry, University of Utah, 315 S. 1400 E, Room 2020, Salt Lake City, Utah 84112-0850, USA
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