Jinhwan Kim, Yanfeng Li, Yan Cheng, Xingcong Ren, Yi Zhang, Cheng Ji, Hua Zhu, Yoshinori Takahashi, Xingdong Xiong, Lixiang Gu, Chrispus Ngule, Xiaofang Xiong, Jianxun Song, Xiaoqi Liu, Jin-Ming Yang
Mitochondria continuously undergo morphologically dynamic processes of fusion and fission to maintain their size, shape, amount, and function; yet the precise molecular mechanisms by which mitochondrial dynamics is regulated remain to be fully elucidated. Here, we report a previous unappreciated but critical role of eukaryotic elongation factor 2 (eEF2) in regulating mitochondrial fission. eEF2, a G-protein superfamily member encoded by EEF2 gene in humans, has long been appreciated as a promoter of the GTP-dependent translocation of the ribosome during protein synthesis. We found unexpectedly in several types of cells that eEF2 was not only present in the cytosol but also in the mitochondria. Furthermore, we showed that mitochondrial length was significantly increased when the cells were subjected to silencing of eEF2 expression, suggesting a promotive role for eEF2 in the mitochondrial fission. Inversely, overexpression of eEF2 decreased mitochondrial length, suggesting an increase of mitochondrial fission. Inhibition of mitochondrial fission caused by eEF2 depletion was accompanied by alterations of cellular metabolism, as evidenced by a reduction of oxygen consumption and an increase of oxidative stress in the mitochondria. We further demonstrated that eEF2 and Drp1, a key driver of mitochondrial fission, colocalized at the mitochondria, as evidenced by microscopic observation, coimmunoprecipitation, and GST pulldown assay. Deletion of the GTP-binding motif of eEF2 decreased its association with Drp1 and abrogated its effect on mitochondria fission. Moreover, we showed that wild-type eEF2 stimulated GTPase activity of Drp1, whereas deletion of the GTP-binding site of eEF2 diminished its stimulatory effect on GTPase activity. This work not only reveals a previously unrecognized function of eEF2 (i.e., promoting mitochondrial fission), but also uncovers the interaction of eEF2 with Drp1 as a novel regulatory mechanism of the mitochondrial dynamics. Therefore, eEF2 warrants further exploration for its potential as a therapeutic target for the mitochondria-related diseases.
{"title":"Identification of elongation factor-2 as a novel regulator of mitochondrial fission","authors":"Jinhwan Kim, Yanfeng Li, Yan Cheng, Xingcong Ren, Yi Zhang, Cheng Ji, Hua Zhu, Yoshinori Takahashi, Xingdong Xiong, Lixiang Gu, Chrispus Ngule, Xiaofang Xiong, Jianxun Song, Xiaoqi Liu, Jin-Ming Yang","doi":"10.1002/ntls.20220011","DOIUrl":"https://doi.org/10.1002/ntls.20220011","url":null,"abstract":"Mitochondria continuously undergo morphologically dynamic processes of fusion and fission to maintain their size, shape, amount, and function; yet the precise molecular mechanisms by which mitochondrial dynamics is regulated remain to be fully elucidated. Here, we report a previous unappreciated but critical role of eukaryotic elongation factor 2 (eEF2) in regulating mitochondrial fission. eEF2, a G-protein superfamily member encoded by <i>EEF2</i> gene in humans, has long been appreciated as a promoter of the GTP-dependent translocation of the ribosome during protein synthesis. We found unexpectedly in several types of cells that eEF2 was not only present in the cytosol but also in the mitochondria. Furthermore, we showed that mitochondrial length was significantly increased when the cells were subjected to silencing of eEF2 expression, suggesting a promotive role for eEF2 in the mitochondrial fission. Inversely, overexpression of eEF2 decreased mitochondrial length, suggesting an increase of mitochondrial fission. Inhibition of mitochondrial fission caused by eEF2 depletion was accompanied by alterations of cellular metabolism, as evidenced by a reduction of oxygen consumption and an increase of oxidative stress in the mitochondria. We further demonstrated that eEF2 and Drp1, a key driver of mitochondrial fission, colocalized at the mitochondria, as evidenced by microscopic observation, coimmunoprecipitation, and GST pulldown assay. Deletion of the GTP-binding motif of eEF2 decreased its association with Drp1 and abrogated its effect on mitochondria fission. Moreover, we showed that wild-type eEF2 stimulated GTPase activity of Drp1, whereas deletion of the GTP-binding site of eEF2 diminished its stimulatory effect on GTPase activity. This work not only reveals a previously unrecognized function of eEF2 (i.e., promoting mitochondrial fission), but also uncovers the interaction of eEF2 with Drp1 as a novel regulatory mechanism of the mitochondrial dynamics. Therefore, eEF2 warrants further exploration for its potential as a therapeutic target for the mitochondria-related diseases.","PeriodicalId":501225,"journal":{"name":"Natural Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138532704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jieyang Huang, Andréa Martin, Anna Urbanski, Ranjit Kulkarni, Patrick Amsalem, Moritz Exner, Guiping Li, Johannes Müller, David Burmeister, Norbert Koch, Torsten Brezesinski, Nicola Pinna, Petra Uhlmann, Michael J. Bojdys
Silicon-based anodes with lithium ions as charge carriers have the highest predicted theoretical specific capacity of 3579 mA h g−1 (for Li15Si4). Contemporary electrodes do not achieve this theoretical value largely because conventional production paradigms rely on the mixing of weakly coordinated components. In this paper, a semiconductive triazine-based graphdiyne polymer network is grown around silicon nanoparticles directly on the current collector, a copper sheet. The porous, semiconducting organic framework (1) adheres to the current collector on which it grows via cooperative van der Waals interactions, (2) acts effectively as conductor for electrical charges and binder of silicon nanoparticles via conjugated, covalent bonds, and (3) enables selective transport of electrolyte and Li-ions through pores of defined size. The resulting anode shows extraordinarily high capacity at the theoretical limit of fully lithiated silicon. Finally, we combine our anodes in proof-of-concept battery assemblies using a conventional layered Ni-rich oxide cathode.
以锂离子为载流子的硅基阳极具有最高的预测理论比容量3579 mA h g−1(对于Li15Si4)。当代电极不能达到这一理论价值，主要是因为传统的生产模式依赖于弱协调成分的混合。在本文中，一个半导体的三嗪基石墨炔聚合物网络被生长在硅纳米颗粒周围，直接生长在电流收集器(铜片)上。多孔的半导体有机框架(1)通过范德华相互作用附着在电流收集器上，(2)通过共轭共价键有效地充当电荷的导体和硅纳米颗粒的粘合剂，(3)通过规定尺寸的孔选择性地传输电解质和锂离子。所得阳极在完全锂化硅的理论极限下显示出非常高的容量。最后，我们使用传统的层状富镍氧化物阴极将我们的阳极组合在概念验证电池组件中。
{"title":"One-pot synthesis of high-capacity silicon anodes via on-copper growth of a semiconducting, porous polymer","authors":"Jieyang Huang, Andréa Martin, Anna Urbanski, Ranjit Kulkarni, Patrick Amsalem, Moritz Exner, Guiping Li, Johannes Müller, David Burmeister, Norbert Koch, Torsten Brezesinski, Nicola Pinna, Petra Uhlmann, Michael J. Bojdys","doi":"10.1002/ntls.20210105","DOIUrl":"https://doi.org/10.1002/ntls.20210105","url":null,"abstract":"Silicon-based anodes with lithium ions as charge carriers have the highest predicted theoretical specific capacity of 3579 mA h g<sup>−1</sup> (for Li<sub>15</sub>Si<sub>4</sub>). Contemporary electrodes do not achieve this theoretical value largely because conventional production paradigms rely on the mixing of weakly coordinated components. In this paper, a semiconductive triazine-based graphdiyne polymer network is grown around silicon nanoparticles directly on the current collector, a copper sheet. The porous, semiconducting organic framework (1) adheres to the current collector on which it grows via cooperative van der Waals interactions, (2) acts effectively as conductor for electrical charges and binder of silicon nanoparticles via conjugated, covalent bonds, and (3) enables selective transport of electrolyte and Li-ions through pores of defined size. The resulting anode shows extraordinarily high capacity at the theoretical limit of fully lithiated silicon. Finally, we combine our anodes in proof-of-concept battery assemblies using a conventional layered Ni-rich oxide cathode.","PeriodicalId":501225,"journal":{"name":"Natural Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138532697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Front Cover: From atomic physics, to upper-atmospheric chemistry, to cosmology: A “laser photometric ratio star” to calibrate telescopes at major observatories","authors":"Justin E. Albert, Dmitry Budker, H. R. Sadeghpour","doi":"10.1002/ntls.10046","DOIUrl":"https://doi.org/10.1002/ntls.10046","url":null,"abstract":"<b>From Atoms to the Universe</b>","PeriodicalId":501225,"journal":{"name":"Natural Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138532699","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The free propagation in time of a normalisable wave packet is the oldest problem of continuum quantum mechanics. Its motion from microscopic to macroscopic distance is the way in which most quantum systems are detected experimentally. Although much studied and analysed since 1927 and presented in many textbooks, here the problem is re-appraised from the standpoint of semi-classical mechanics. Particular aspects are the emergence of deterministic trajectories of particles emanating from a region of atomic dimension and the interpretation of the wave function as describing a single particle or an ensemble of identical particles. Of possible wave packets, that of Gaussian form is most studied due to the simple exact form of the time-dependent solution in real and in momentum space. Furthermore, this form is important in laser optics. Here the equivalence of the time-dependent Schrödinger equation to the paraxial equation for the propagation of light is demonstrated explicitly. This parallel helps to understand the relevance of trajectory concepts and the conditions necessary for the perception of quantum motion as classical.
{"title":"Trajectories and the perception of classical motion in the free propagation of wave packets","authors":"John S. Briggs","doi":"10.1002/ntls.20210089","DOIUrl":"https://doi.org/10.1002/ntls.20210089","url":null,"abstract":"The free propagation in time of a normalisable wave packet is the oldest problem of continuum quantum mechanics. Its motion from microscopic to macroscopic distance is the way in which most quantum systems are detected experimentally. Although much studied and analysed since 1927 and presented in many textbooks, here the problem is re-appraised from the standpoint of semi-classical mechanics. Particular aspects are the emergence of deterministic trajectories of particles emanating from a region of atomic dimension and the interpretation of the wave function as describing a single particle or an ensemble of identical particles. Of possible wave packets, that of Gaussian form is most studied due to the simple exact form of the time-dependent solution in real and in momentum space. Furthermore, this form is important in laser optics. Here the equivalence of the time-dependent Schrödinger equation to the paraxial equation for the propagation of light is demonstrated explicitly. This parallel helps to understand the relevance of trajectory concepts and the conditions necessary for the perception of quantum motion as classical.","PeriodicalId":501225,"journal":{"name":"Natural Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138532700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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