発表論文
英文原著
- Tachizaki, M., Sakamoto, S., Kobori, Y., Asano, Y., Kawaguchi, S., Seya, K., Tanaka, H., Morita, E. , Imaizumi, T. Interferon-stimulated gene 56 positively regulates Toll-like receptor 3-mediated CXCL10 expression in human renal proximal tubular epithelial cells. FEBS Open Bio. 2024 Aug;14(8):1303-1319. doi: 10.1002/2211-5463.13851.
- Izumida, K., Morita, E. The roles of HCV core protein and its binding host factor in virus assembly and release. Frontiers in Virology 2024 4:1383261 doi:10.3389/fviro.2024.1383261
- Konno, Y., Uriu, K., Chikata, T., Takada, T., Kurita, J.I., Ueda, M.T., Islam, S., Yang, Tan B.J., Ito, J., Aso, H., Kumata, R., Williamson, C., Iwami, S., Takiguchi, M., Nishimura, Y., Morita, E., Satou, Y., Nakagawa, S., Koyanagi, Y., Sato, K. Two-step evolution of HIV-1 budding system leading to pandemic in the human population. Cell Rep. 2024 43(2):113697. doi: 10.1016/j.celrep.2024.113697.
- Izumida, K., Hara, Y., Furukawa, Y., Ishida, K., Tabata, K.,Morita, E. Purification of Hepatitis C Virus Core Protein in Non-Denaturing Condition. J Virol Methods. 2024 Jan; 322:114852 doi: 10.1016/j.jviromet.2023.114852.
- Maeda, K., Goto, S., Miura, K., Saito, K., Morita, E. The Incorporation of Extracellular Vesicle Markers Varies Among Vesicles with Distinct Surface Charges. J Biochem. 2024 175(3):299-312 doi: 10.1093/jb/mvad097.
- Ishida, K., Yagi, H., Kato, Y., Morita, E. N-linked glycosylation of flavivirus E protein contributes to viral particle formation. PLoS Pathog. 2023 19(10):e1011681. doi: 10.1371/journal.ppat.1011681.
- Hashimoto, K., Kimura, K., Ishida, K., Morita, E. Tanaka, K., Hashimoto, M. HIV-1 Integrase Inhibitor, Dihydroobionin B, and the Investigation of its Extraordinary Specific Rotation. J Nat Prod. 2023 86(9): 2139-2144. 10.1021/acs.jnatprod.3c00353
- Miura, K., Suzuki, Y., Ishida, K., Arakawa, M., Wu, H., Fujioka, Y., Emi, A., Maeda, K., Hamajima, R., Nakano, T., Tenno, T., Hiroaki, H., Morita, E. Distinct Motifs in the E Protein are Required for SARS-CoV-2 Virus Particle Formation and Lysosomal Deacidification in Host Cells. J Virol. 2023 e0042623. doi: 10.1128/jvi.00426-23.
- Arakawa, M., Morita, E. Protein Pull-down Assay Using HiBiT-tag-dependent Luciferase Activity Measurement. Bioprotocol. 2023 13(6) e4640. DOI: 10.21769/BioProtoc.4640
- Miura, S., Ishida, K., Tanaka, K., Morita, E. Hashimoto, M. Integrasone derivatives isolated from Lepteutypa sp. KT4162 and their anti-HIV-1 integrase activity. J Nat Prod. 2023 86, 4, 1019–1024 DOI: 10.1021/acs.jnatprod.3c00065
- Arakawa, M., Yoshida, A., Okamura, S., Ebina, H., Morita, E. A highly sensitive NanoLuc-based protease biosensor for detecting apoptosis and SARS-CoV-2 infection. Sci Rep. 2023 13(1)1753. Doi: 10.1038/s41598-023-28984-4
- Ishida, K., Noguchi, T., Kimura, S., Suzuki, H., Ebina, H., Morita E. Tracking of human parvovirus B19 virus-like particles using short peptide tags reveals a membrane-associated extracellular release of these particles. J Virol. 2023 e0163122. Doi: 10.1128/jvi.01631-22
- Morita, E. ESCRT-mediated plasma membrane shaping. Plasma Membrane Shaping 1st Edition, Academic Press, 2022 Chapter 7 p91- 103 eBook ISBN 9780323899192, Paper Book ISBN 9780323899116 doi: 10.1016/B978-0-323-89911-6.00003-0
- Suzuki, H., Noguchi, T., Matsugu, N., Suzuki, A., Kimura, S., Onishi, M., Kosaka, M., Miyazato, P., Morita, E., Ebina, H. Safety and immunogenicity of parvovirus B19 virus-like particle vaccine lacking phospholipase A2 activity. 2022 40(42):6100-6106. doi: 10.1016/j.vaccine.2022.09.009.
- Liu, CC., Liu, YY., Zhou, JF., Chen, X., Chen, H., Hu, JH., Chen, J., Zhang, J., Sun, RC., Wei, JC., Go, YY., Morita, E., Zhou, B. Cellular ESCRT components are recruited to regulate the endocytic trafficking and RNA replication compartment assembly during classical swine fever virus infection. PLoS Pathog. 2022, 18(2):e1010294. doi: 10.1371/journal.ppat. 1010294.
- Arakawa, M., Tabata, K., Ishida, K., Kobayashi, M., Arai, A., Ishikawa, T., Suzuki, R., Takeuchi, H., Tripathi, LP., Mizuguchi, K., Morita, E.. Flavivirus recruits the valosin-containing protein (VCP)/NPL4 complex to induce stress granule disassembly for efficient viral genome replication. J Biol Chem. 2022 298(3):101597, doi: 10.1016/j.jbc.2022.101597.
- Okudera, M., Odawara, M., Arakawa, M., Kawaguchi, S., Seya, K., Matsumiya, T., Sato, R., Ding, J.,Morita, E.. , Imaizumi, T. Expression of Zinc-finger antiviral protein in hCMEC/D3 human cerebral microvascular endothelial cells: effect of a Toll-like receptor 3 agonist. Neuroimmunomodulation 2021 Dec 22:1-10. doi: 10.1159/000521012.
- Suzuki, H., Noguchi, T., Ogawa, K., Miyazato, P., Hatakeyama, Y., Morita, E.. , Ebina, H. Fusion of parvovirus B19 receptor-binding domain and pneumococcal surface protein A induces protective immunity against parvovirus B19 and Streptococcus pneumoniae. Vaccine 2021, 39(36):5146-5152. doi: 10.1016/j.vaccine.2021.07.046.
- Morita, E. , Suzuki, Y. Membrane-Associated Flavivirus Replication Complex—Its Organization and Regulation. Viruses 2021, 13(6), 1060 doi: 10.3390/v13061060
- Kimura, S., Maeda, K., Nagashima, R., Miura, K., Ebina, H., Tanaka, N., Morita, E. Efficient immunogenic peptide antigen delivery to dendritic cells using an ESCRT-mediated extracellular vesicle formation method. Vaccine 2021, 39(22), 2976-2982. doi: 10.1128/JVI.02234-20.
- Tabata, K., Arakawa, M., Ishida, K., Kobayashi, M., Nara, A., Sugimoto, T., Okada, T., Mori K., Morita, E. Endoplasmic reticulum-associated degradation controls virus protein homeostasis that is required for the flavivirus propagation. J Virol. 2021 May 12:JVI.02234-20. doi: 10.1016/j.vaccine.2021.04.021.
- Ozaki, R., Ishida, K., Morita, E. , Hanada, Y. Nanoparticle deposition of fluoropolymer CYTOP via holographic femtosecond laser processing and its biochip application. Applied Sciences. 2020, 10(20), 7243
- Goto, S., Ishida, K., Suzuki, R., Morita, E. . Split nano luciferase-based assay to measure assembly of Japanese encephalitis virus. Bioprotocol. 2020 May 5, 10:9 e3606.
- Tayone, WC., Ishida, K., Goto, S., Tayone, JC., Arakawa, M., Morita, E. , and Hashimoto, M. Anti-Japanese Encephalitis Virus (JEV) Activity of Triterpenes and Flavonoids from Euphorbia hirta. Philippine Journal of Science. 2020 149 (3): 603-613
- Arakawa, M., Morita, E. Zika virus infection and replication organelle biogenesis. Elsevier “Zika Virus Biology, Pathology and Control” 2020 in press.
- Ishida, K., Goto, S., Ishimura, M., Amanuma, M., Hara, Y., Suzuki, R., Katoh, K., Morita, E. Functional correlation between subcellular localizations of Japanese encephalitis virus capsid protein and virus production. J Virol. 2019 Jul 17. pii: JVI.00612-19.
- Arakawa, M., Morita, E. Flavivirus replication organelle biogenesis in the endoplasmic reticulum: comparison with other single-stranded positive-sense RNA viruses. Int J Mol Sci. 2019 20:2336
- Morita, E. Membrane closure in stress induced-autophagosome formation. Cell Stress. 2018 2(6):122-124
- Tripathi, L.P., Chen, Y. A., Mizuguchi, K andMorita, E. Network-based analysis of host-pathogen interactions. Encyclopedia of Bioinformatics and Computational Biology. 2019 3:932-937
- Tabata, K., Nara, A., Omori, H.,Morita, E. Immuno-localization of ESCRT proteins in virus-infected cells by fluorescence and electron microscopy. Methods in Molecular Biology. 2019 1998:73-92.
- Tabata, K., Arimoto, M., Arakawa, M., Nara, A., Saito, K., Omori, H., Arai, A., Ishikawa, T., Konishi, E., Suzuki, R., Matsuura, Y., Morita, E. Unique Requirement for ESCRT Factors in Flavivirus Particle Formation on the Endoplasmic Reticulum. Cell Rep. 2016 16(9):2339-2347
- Hao, F., Itoh, T., Morita, E., Shirahama-Noda, K., Yoshimori, T., Noda, T. The PtdIns3-phosphatase MTMR3 interacts with mTORC1 and suppresses its activity. FEBS Lett. 2016 590(1):161-173.
- Suzuki, H., Tabata, K., Morita, E., Kawasaki, M., Kato, R., Dobson, RJ., Yoshimori, T., Wakatsuki, S. Structural basis of the autophagy-related LC3/Atg13 LIR complex: recognition and interaction mechanism. Structure. 2014 22(1):47-58.
- Fujita, N.†, Morita, E. †, Itoh, T., Tanaka, A., Nakaoka, M., Osada, Y., Umemoto, T., Saitoh, T., Nakatogawa, H., Kobayashi, S., Haraguchi, T., Guan, J.L., Iwai, K., Tokunaga, F., Saito, K., Ishibashi, K., Akira, S., Fukuda, M., Noda, T., Yoshimori, T. Recruitment of the autophagic machinery to endosomes during infection is mediated by ubiquitin. J Cell Biol. 2013 203(1):115-28 †These authors contributed equally
- Tripathi, L.P., Kambara, H., Chen, Y.A., Nishimura, Y., Moriishi, K., Okamoto, T., Morita, E., Abe, T., Mori, Y., Matsuura, Y., Mizuguchi, K. Understanding the biological context of NS5A-host interactions in HCV infection: a network-based approach. J Proteome Res. 2013 Jun 7;12(6):2537-51.
- Katoh, H., Okamoto, T., Fukuhara, T., Kambara, H., Morita, E., Mori, Y., Kamitani, W., Matsuura, Y. Japanese encephalitis virus core protein inhibits stress granule formation through an interaction with Caprin-1 and facilitates viral propagation. J Virol. 2013 Jan;87(1):489-502.
- Morita, E., Arii J, Christensen D, Votteler J, Sundquist WI. Attenuated protein expression vectors for use in siRNA rescue experiments. Biotechniques. 2012 Aug;0(0):1-5.
- Tripathi LP, Kambara H, Moriishi K, Morita E, Abe T, Mori Y, Chen YA, Matsuura Y, Mizuguchi K. Proteomic analysis of hepatitis C virus (HCV) core protein transfection and host regulator PA28γ knockout in HCV pathogenesis: a network-based study. J Proteome Res. 2012 Jul 6;11(7):3664-79.
- Fukuhara T, Kambara H, Shiokawa M, Ono C, Katoh H,Morita, E., Okuzaki D, Maehara Y, Koike K, Matsuura Y. Expression of microRNA miR-122 facilitates an efficient replication in nonhepatic cells upon infection with hepatitis C virus. J Virol. 22012 Aug;86(15):7918-33.
- Morita, E., Yoshimori, T. Membrane recruitment of LC3 proteins during autophagosome formation. Hepatol Res. 2012 May;42(5):435-41.
- Morita, E. ESCRT Connections: Factor Requirements for Multivesicular Body Formation, Virus Budding and Cell Division. FEBS J. 2012 Apr;279(8):1399-406
- Katoh, H., Mori, Y., Kambara, H., Abe, T., Fukuhara, T., Morita, E., Moriishi, K., Kamitani, W., Matsuura, Y. Heterogeneous nuclear ribonucleoprotein A2 participates in the replication of Japanese encephalitis virus through an interaction with viral proteins and RNA. J Virol. 2011 85(21):10976-88
- Morita, E., Sandrin, V., McCullough, J., Katsuyama, A., Hamilton, IB., Sundquist, WI. ESCRT-III protein requirements for HIV-1 budding. Cell Host Microbe. 2011, 3:235-42.
- Matsunaga, K., Morita, E., Saitoh, T., Akira, S., Ktistakis, NT., Izumi, T., Noda, T., Yoshimori, T. Autophagy requires endoplasmic reticulum targeting of the PI3-kinase complex via Atg14L. J Cell Biol. 2010 190(4):511-21.
- Morita, E., Colf, LA., Karren, MA., Sandrin, V., Rodesch, CK., Sundquist, WI. Human ESCRT-III and VPS4 proteins are required for centrosome and spindle maintenance. Proc Natl Acad Sci U S A. 2010 107(29):12889-94.
- Bajorek, M., Morita, E., Skalicky, JJ, Morham, SG., Babst, M., Sundquist, WI. Biochemical analyses of human IST1 and its function in cytokinesis. Mol Biol Cell 2009 20(5):1360-73.
- Kieffer, C., Skalicky JJ., Morita, E., De Domenico, I., Ward, DM., Kaplan, J., Sundquist, WI. A New Functionally Important ESCRT-III Recognition Mode for the VPS4 ATPases. Dev. Cell 2008, 15(1):62-73.
- Chung, HY., Morita, E., von Schwedler, U., Müller, B., Kräusslich, HG. and Sundquist, WI.. NEDD4L Overexpression Rescues Release and Infectivity of HIV-1 Constructs Lacking PTAP and YPXL Late Domains. J Virol. 2008, 82(10):4884-97.
- Morita, E., Sandrin, V., Chung, HY., Morham, SG., Gygi, SP., Rodesch, CK. and Sundquist,, WI. Human ESCRT and ALIX Proteins Interact with Proteins of the Midbody and Function in Cytokinesis. EMBO J, 2007, 26(19):4215-27.
- Morita, E., Sandrin, V., Alam, SL., Eckert, DM., Gygi, SP., Sundquist, WI. Identification of MVB12 Proteins as Human ESCRT-I Subunits that Function in HIV Budding. Cell Host Microbe 2007, 2(1):19-28
- Morita, E., Sundquist, WI. Retrovirus budding. Annu Rev Cell Dev Biol. 2004 20:395-425.
- Nakashima, A., Morita, E., Saito, S., Sugamura, K. Human Parvovirus B19 nonstructural protein transactivates the p21/WAF1 through Sp1. Virology 2004 329:493-504.
- von Schwedler, UK., Stuchell, M., Muller, B., Ward, DM., Chung, HY., Morita, E., Wang, HE., Davis, T., He, GP., Cimbora, DM., Scott, A., Krausslich, HG., Kaplan, J., Morham, SG., Sundquist, WI. The protein network of HIV budding. Cell. 2003 114:701-13.
- Kanazawa, C., Morita, E., Yamada, M., Ishii, N., Miura, S., Asao, H., Yoshimori, T., Sugamura, K. Effects of deficiencies of STAMs and Hrs, mammalian class E Vps proteins, on receptor downregulation. Biochem Biophys Res Commun. 2003 309:848-56.
- Morita, E., Nakashima, A., Asao, H., Sato, H., Sugamura, K. Human parvovirus B19 nonstructural protein (NS1) induces cell cycle arrest at G(1) phase. J Virol. 2003 77:2915-21.
- Morita, E., Sugamura, K. Human parvovirus B19-induced cell cycle arrest and apoptosis. Springer Semin Immunopathol 2002 24:187-199.
- Chisaka, H., Morita, E., Murata, K., Ishii, N., Yaegashi, N., Sugamura, K. A transgenic mouse model for nonimmune hydrops fetalis induced by the NS1 gene of human parvovirus B19. J Gen Virol. 2002 83:273-81.
- Morita, E., Tada, K., Chisaka, H., Asao, H., Sato, H., Yaegashi, N., Sugamura, K. Human parvovirus B19 induces cell cycle arrest at G(2) phase with accumulation of mitotic cyclins. J Virol. 2001 75:7555-63.
- Kasai, H., Morita, E., Hatakeyama, K., Sugiyama K. Characterization of haemagglutinin -esterase protein (HE) of murine corona virus DVIM by monoclonal antibodies. Arch Virol. 1998;143:1941-8.
- Morita, E., Ebina, H., Muto, A., Himeno, H., Hatakeyama, K., Sugiyama, K. Primary structures of hemagglutinin-esterase and spike glycoproteins of murine coronavirus DVIM. Virus Genes 1998;17:123-8.
和文総説
- 森田英嗣 細胞外微粒子に積荷をローディングする方法の概念と応用 実験医学別冊 決定版エクソソーム実験ガイド 171-174 2020
- 森田英嗣 ゼノファジーの分子機構 医学のあゆみ 272:9 826-832 2020
- 森田英嗣 プラス鎖RNAウイルスによって形成される複製オルガネラの構造と形成の分子機構 生化学 2017 89:5 744-747
- 森田英嗣 細胞内病原体の増殖を制御するオートファジー機構 最新医学 2016 72:2 240-249
- 田端桂介、森田英嗣 ウイルス感染とオートファジー 臨床免疫・アレルギー科 2016 66:4 330-336
- 森田英嗣 Multivesicular Bodyの形成とESCRT複合体の役割 生体の科学 2012 65:522-525
- 森田英嗣 エンベロープウイルスの出芽と細胞質分裂 生化学 2010 82:415-419
- 森田英嗣 エンベロープウイルス粒子形成の分子メカニズム 蛋白質 核酸 酵素 増刊号「メンブレントラフィックの奔流」.蛋白質 核酸 酵素 2008 53:2245-2250.
- 八重樫伸生、千坂泰、森田英嗣、多田孝太郎、岡村州博、菅村和夫 パルボウイルスB19の母子感染 ウイルス 2001 51:51-56
招待講演等
- Morita, E., Intracellular membrane remodeling in Flavivirus infected cells. 第44回日本分子生物学会年会 Symposium ”Molecular bases of membrane remodeling and organization”, invited lecture, 横浜. 2021年12月 第44回日本分子生物学会年会シンポジウム「膜のリモデリングと組織化の分子基盤」
- 森田 英嗣 第94回日本細菌学会総会 シンポジウム 招待講演 オンライン. 細胞膜損傷を認識するオートファジーレセプターの同定とサルモネラに対するゼノファジーにおける役割. 2021年3月
- 森田 英嗣 第93回日本生化学会大会 シンポジウム招待講演 オンライン. 細胞膜損傷を認識するオートファジーレセプターの同定とゼノファジーにおける役割. 2020年9月
- Morita, E. 江蘇省農業科学院セミナー(江蘇省農業科学院) 南京 中国.Cellular Factors Involved in the Formation of Flavivirus Replication Organelle. 2019年11月
- Morita, E. 南京農業大学セミナー(南京農業大学) 南京 中国. Cellular Factors Involved in the Formation of Flavivirus Replication Organelle. 2019年11月
- 森田 英嗣 第3回オルガネラゾーン研究会 (東京大学)東京.ウイルスの増殖に必要な小胞体応答ゾーン. 2019年11月
- 森田 英嗣 メディカルサイエンスフォーラム・ランチョンセミナー 細胞外小胞形成の分子機構. (弘前大学) 弘前. 2019年11月
- 森田 英嗣 第92回日本生化学会大会. シンポジウム 招待講演 フラビウイルスの増殖に必要な小胞体応答ゾーン. 横浜2019.9
- 森田 英嗣 第41回日本分子生物学会年会. シンポジウム 招待講演 フラビウイルスの複製オルガネラ形成におけるVCP/p97の役割 横浜 2018.11
- 森田 英嗣 第91回日本生化学会大会. シンポジウム 招待講演 フラビウイルス感染時に誘導されるウイルス複製オルガネラ形成・維持の分子機構. 京都 2018.9
- 森田 英嗣 名古屋大学セミナー 招待講演、 2016.9 フラビウイルス増殖に関与する宿主因子の同定と機能解析
- 森田 英嗣 北海道大学獣医学部セミナー 招待講演、 2016.6 フラビウイルス増殖に関与する宿主因子の同定と機能解析
- Morita, E.,The 65th Annual Meeting of the Japan Society for Cell Biology. Invited Lecture. 2013.6 Nagoya. Involvement of ESCRT Factors in Flavivirus Replication.
- 森田 英嗣 第10回ウイルスキャンプ 教育講演 2013.5 ESCRT経路を介したRNAエンベロープウイルス粒子形成の分子メカニズム
- 森田 英嗣 第19回トガ・フラビ・ペスチウイルス研究会 特別講演 2012.11 ESCRT経路を介したRNAエンベロープウイルス粒子形成の分子機構3. 森田 英嗣 第19回トガ・フラビ・ペスチウイルス研究会 特別講演 2012.11 ESCRT経路を介したRNAエンベロープウイルス粒子形成の分子機構
- Morita, E., Invited Lecture. Institute for Tropical Medicine. Nagasaki University., 2012.7 Mechanisms of enveloped RNA virus budding and cytokinesis.
- 森田 英嗣 京都大学ウイルス研究所セミナー 招待講演、京都大学 2012.6 ESCRT経路を介したRNAエンベロープウイルス粒子形成の分子メカニズム
- 森田 英嗣 大阪大学微生物病研究所セミナー 招待講演、大阪大学2010.10 Multivesicular body とオートファゴソーム膜形成の分子メカニズム
- Morita, E.,, 11th KUMAMOTO AIDS Seminar, Invited Lecture, Kumamoto Oct 2010, Identification of the ESCRT-III proteins required for HIV budding
- Morita, E.,, Kobe University Global COE Program on Integrative Membrane Biology 4th Workshop, Invited Lecture, July 2010 Awaji, Identification of the ESCRT-III proteins required for retrovirus budding and cell division
- Morita, E.,, International Symposium on Organelle Network: Microbiology, Immunology, and Cell Biology, Invited Lecture, July 2010, Identification of the ESCRT-III proteins required for retrovirus budding and cell division
- 森田 英嗣 第57回日本ウイルス学会学術集会ワークショップ口頭発表、東京2010.10レトロウイルスの出芽に必要なESCRT-IIIの同定
- 森田 英嗣 弘前大学遺伝子実験施設セミナー 招待講演、弘前大学2009. 7. HIV Budding and Cell Division
- Morita, E.,, Sandrin, V., Sundquist, WI. Identification of the ESCRT-III Proteins Required for Retrovirus Budding. Cold Spring Harbor Laboratory Meeting, Retrovirus, New York, USA (May 2009) *oral presentation
- 森田 英嗣 BMB2008シンポジウム口頭発表 神戸2008.12 細胞質分裂におけるESCRT経路の役割
- Morita, E., Tokyo Institute of Technology, Invited Lecture. Dec. 2008. HIV Budding and Cell Division
- 森田 英嗣 東京大学医科学研究所学友会セミナー 招待講演 東京大学2008.12 HIV-1粒子出芽と細胞分裂
- 森田 英嗣 国立感染症研究所 招待講演 東京大学2008.12 HIV-1粒子出芽と細胞分裂
- 森田 英嗣 東北大学大学院医学系研究科セミナー 招待講演 東北大学2008.7 ESCRT-I結合分子の同定とHIV-1粒子出芽における役割
- 森田 英嗣 大阪大学微生物病研究所セミナー 招待講演 大阪大学2008.7 ESCRT-I結合分子の同定とHIV-1粒子出芽における役割
- Morita, E., Sandrin, V., Karren, MA., Gygi, SP., Morham, SG., Sundquist. WI. Identification of ESCRT-I Binding Factors Required for Efficient HIV-1 Release. Keystone Symposia, HIV Pathogenesis, 275, Banff, Canada, March 2008 *oral presentation
- Morita, E.,Sandrin, V., Karren, MA., Gygi, SP., Morham, SG., Sundquist, WI. Identification of ESCRT-I Binding Factors Required for Efficient HIV-1 Release. 15th Conference on Retroviruses and Opportunistic Infection, 102, Boston, USA, February 2008 *oral presentation