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Jun S, Ro HJ, Bharda A, Kim SI, Jeoung D, Jung HS. Advances in Cryo-Correlative Light and Electron Microscopy: Applications for Studying Molecular and Cellular Events. Protein J 2020; 38:609-615. [PMID: 31396855 DOI: 10.1007/s10930-019-09856-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Cryo-correlative light and electron microscopy (Cryo-CLEM) is materializing as a widespread approach amalgamating the advantages of both fluorescence light microscopy (FLM) as well as three dimensional (3D) cryo-electron tomography (cryo-ET) to reveal the ultrastructure of significant target molecules with specific cellular functions. Cryo-CLEM allows imaging of cells by means of fluorescence microscopy exhibiting the location of the destined molecule at high temporal and spatial resolution while cryo-ET is employed to analyze the 3D structure at a molecular resolution in close-to-physiological condition. Present review focuses upon the practical strategies for Cryo-CLEM and recent technical developments that will assist the broad implementation of this technique to investigate and answer questions pertaining to various biological events occurring in the cell.
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Affiliation(s)
- Sangmi Jun
- Drug & Disease Target Team, Korea Basic Science Institute, 162, Yeongudanji-ro, Ochang-eup, Cheongwon-gu, Cheongju-Si, Chungcheongbuk-do, 28119, South Korea. .,Convergent Research Center for Emerging Virus Infection, Korea Research Institute of Chemical Technology, Daejeon, South Korea. .,Bio-Analytical Science, University of Science & Technology, Daejeon, South Korea.
| | - Hyun-Joo Ro
- Drug & Disease Target Team, Korea Basic Science Institute, 162, Yeongudanji-ro, Ochang-eup, Cheongwon-gu, Cheongju-Si, Chungcheongbuk-do, 28119, South Korea.,Convergent Research Center for Emerging Virus Infection, Korea Research Institute of Chemical Technology, Daejeon, South Korea.,Bio-Analytical Science, University of Science & Technology, Daejeon, South Korea
| | - Anahita Bharda
- Department of Biochemistry, College of Natural Sciences, Kangwon National University, 1 Kangwondaehak-gil, Chuncheon-Si, Gangwon-do, 200-701, South Korea
| | - Seung Il Kim
- Drug & Disease Target Team, Korea Basic Science Institute, 162, Yeongudanji-ro, Ochang-eup, Cheongwon-gu, Cheongju-Si, Chungcheongbuk-do, 28119, South Korea.,Convergent Research Center for Emerging Virus Infection, Korea Research Institute of Chemical Technology, Daejeon, South Korea.,Bio-Analytical Science, University of Science & Technology, Daejeon, South Korea
| | - Dooil Jeoung
- Department of Biochemistry, College of Natural Sciences, Kangwon National University, 1 Kangwondaehak-gil, Chuncheon-Si, Gangwon-do, 200-701, South Korea
| | - Hyun Suk Jung
- Department of Biochemistry, College of Natural Sciences, Kangwon National University, 1 Kangwondaehak-gil, Chuncheon-Si, Gangwon-do, 200-701, South Korea.
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Multiple dynamin family members collaborate to drive mitochondrial division. Nature 2016; 540:139-143. [PMID: 27798601 PMCID: PMC5656044 DOI: 10.1038/nature20555] [Citation(s) in RCA: 357] [Impact Index Per Article: 44.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 10/24/2016] [Indexed: 12/11/2022]
Abstract
Mitochondria cannot be generated de novo; they must grow, replicate their genome, and divide in order to be inherited to each daughter cell during mitosis. Mitochondrial division is a structural challenge that requires a massive remodeling of membrane morphology 1–3. Although division factors differ across organisms, the need for multiple constriction steps and a dynamin-related protein (Drp1, Dnm1 in yeast) has been conserved 4–6. In mammalian cells, mitochondrial division has been shown to proceed with at least two sequential constriction steps: 1. endoplasmic reticulum (ER) and actin collaborate to generate constrictions suitable for Drp1 assembly; 2. Drp1 further constricts membranes until fission occurs 2,7–9. However, in vitro experiments argue that Drp1 does not have the dynamic range to complete membrane fission per se7. In contrast to Drp1, the neuronal-specific classical Dynamin-1 (Dyn1) has been shown to assemble on narrower lipid profiles and facilitates spontaneous membrane fission upon GTP hydrolysis 10,11. Here we discovered that the ubiquitously-expressed classical Dynamin-2 (Dyn2) is a fundamental component of the mitochondrial division machinery. A combination of live-cell and electron microscopy reveals that Dyn2 works in concert with Drp1 to orchestrate sequential constriction events leading up to division. Our work underscores the biophysical limitations of Drp1 and positions Dyn2, which has intrinsic membrane fission properties, at the final step of mitochondrial division.
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Hatch AL, Gurel PS, Higgs HN. Novel roles for actin in mitochondrial fission. J Cell Sci 2014; 127:4549-60. [PMID: 25217628 DOI: 10.1242/jcs.153791] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Mitochondrial dynamics, including fusion, fission and translocation, are crucial to cellular homeostasis, with roles in cellular polarity, stress response and apoptosis. Mitochondrial fission has received particular attention, owing to links with several neurodegenerative diseases. A central player in fission is the cytoplasmic dynamin-related GTPase Drp1, which oligomerizes at the fission site and hydrolyzes GTP to drive membrane ingression. Drp1 recruitment to the outer mitochondrial membrane (OMM) is a key regulatory event, which appears to require a pre-constriction step in which the endoplasmic reticulum (ER) and mitochondrion interact extensively, a process termed ERMD (ER-associated mitochondrial division). It is unclear how ER-mitochondrial contact generates the force required for pre-constriction or why pre-constriction leads to Drp1 recruitment. Recent results, however, show that ERMD might be an actin-based process in mammals that requires the ER-associated formin INF2 upstream of Drp1, and that myosin II and other actin-binding proteins might be involved. In this Commentary, we present a mechanistic model for mitochondrial fission in which actin and myosin contribute in two ways; firstly, by supplying the force for pre-constriction and secondly, by serving as a coincidence detector for Drp1 binding. In addition, we discuss the possibility that multiple fission mechanisms exist in mammals.
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Affiliation(s)
- Anna L Hatch
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Pinar S Gurel
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Henry N Higgs
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
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Cao M, Wang F, Qiao ZW, Zhang HB, Nishi R. Electron tomographic resolution of microns-thick specimens in the ultrahigh voltage electron microscope. Micron 2013; 49:71-4. [PMID: 23528481 DOI: 10.1016/j.micron.2013.02.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 02/25/2013] [Accepted: 02/25/2013] [Indexed: 11/29/2022]
Abstract
In this study, we determine the electron tomography (ET) resolution for microns-thick specimens by experiment in the ultra-high voltage electron microscope. A tilt series of projection images of a tilted 8μm thick epoxy-resin film are first acquired. Tomographic reconstructions are then calculated and the resolution is evaluated with the Fourier shell correlation method. The ET resolution of 32nm is achieved under the condition of 2MV accelerating voltage. We also demonstrate that some high tilt angle projections may be little useful for improving the final ET resolution because of the corresponding poor image qualities. These results are helpful to understand the possibility and limitation of ET applications in microns-thick specimens.
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Affiliation(s)
- Meng Cao
- Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Department of Electronic Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
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