Review Paper 12
古川 良明*
脳神経内科 2023 Vol. 99, pp. 776-781


古川 良明*
化学と教育 2023 Vol. 71, pp. 298-301

Original Paper 53
Furukawa Y*, Shintani A, Narikiyo S, Sue K, Akutsu M, and Muraki N
“Characterization of a novel cysteine-less Cu/Zn-superoxide dismutase in Paenibacillus lautus missing a conserved disulfide bond”
Journal of Biological Chemistry 2023 in press

Copper-zinc superoxide dismutase (CuZnSOD) is an enzyme that catalyzes the disproportionation of superoxide and is conserved from bacteria to humans. It binds copper and zinc ions and also forms an intramolecular disulfide bond. We have previously shown that the intramolecular disulfide bond plays a critical role in both structural stability and enzymatic activity and is therefore highly conserved in CuZnSOD. However, a close examination of CuZnSODs in the NCBI database revealed that some CuZnSODs in Paenibacillus (Gram-positive bacteria), named PaSOD, lack cysteines and are expected to have a novel domain structure. Therefore, in this study, we investigated the expression, activity and structure of PaSOD and discussed the physiological significance of the lack of cysteines in CuZnSOD in Paenibacillus.


Original Paper 52
Hashimoto K, Watanabe S, Akutsu M, Muraki N, Kamishina H, Furukawa Y, and Yamanaka K*
“Intrinsic structural vulnerability in the hydrophobic core induces species-specific aggregation of canine SOD1 with degenerative myelopathy–linked E40K mutation”
Journal of Biological Chemistry 2023 Vol. 299, 104798
Press Release from Keio Univ.
Press Release from Nagoya Univ.

SOD1 mutations are one of the causes of amyotrophic lateral sclerosis (ALS), and mutations (E40K) in the SOD1 gene in dogs also cause degenerative myelopathy (DM), a motor neuron disease similar to ALS. Like ALS, mutation-induced amino acid substitution (E40K) is considered to affect the structure of canine SOD1 (cSOD1) and cause the disease; however, the details are not clear. In this study, Prof. Koji Yamanaka’s group at Nagoya University found that when methionine, the 117th amino acid of cSOD1, is replaced with leucine, the structural abnormality of cSOD1 caused by E40K mutation is not observed. Therefore, our group performed crystallographic analysis to clarify the reason why the E40K-cSOD1 structural abnormality is not observed by the M117L mutation. As a result, the methionine is located in the hydrophobic core of the cSOD1 structure but also creates a void in its vicinity. On the other hand, substitution of leucine, a hydrophobic amino acid slightly larger in size than methionine, was found to fill the void exactly (see figure below), which is considered to result in the structural stabilization of cSOD1. Since the 117th amino acid in human SOD1 is leucine, canine SOD1 is more structurally unstable than human SOD1 and also more vulnerable to amino acid substitutions such as E40K.


Original Paper 51
Furukawa Y*, Matsumoto K, Nakagome K, Shintani A, and Sue K
“Zinc-mediated interaction of copper chaperones through their heavy-metal associated domains”
Journal of Trace Elements in Medicine and Biology 2023 Vol.75, 127111

Our study on copper chaperones has been published in Journal of Trace Elements in Medicine and Biology (IF = 3.995).  A copper chaperone for superoxide dismutase, CCS, is known to be responsible for delivering a copper ion to superoxide dismutase (SOD1), but we have shown that CCS can interact with another copper chaperone, HAH1, through a zinc ion.  This study has actually a long history (almost 10 years?) in our lab and is an achievement of the struggles by Mr. Nakagome and Ms. Matsumoto.  It is quite interesting that distinct copper-delivering proteins (i.e. copper chaperones) interact with each other through a zinc (but not copper) ion.  Nonetheless, the interaction is relatively weak, and its physiological relevance remains obscure.  We still have a lot of work to do!

銅シャペロンに関する私たちの研究が、Journal of Trace Elements in Medicine and Biology (IF = 3.995)に掲載されました。CCSという銅シャペロンタンパク質は、SOD1に銅イオンを運ぶ役割を担っていますが、別の銅シャペロンタンパク質であるHAH1と亜鉛イオンを介して相互作用することを見出しました。この研究を始めてから10年近く経ってしまいましたが、卒業生の中込君や松本さんの奮闘もあって、なんとか形にすることができました。銅イオンを運ぶタンパク質が亜鉛イオンを介して相互作用するというのは非常に面白いと思うのですが、相互作用は比較的弱く、その生理的意義は不明のままです。まだまだやるべきことが残っているということでしょうか。

Original Paper 50
Moriyama Y, Ogata G, Nashimoto H, Sawamura S, Furukawa Y, Hibino H, Kusuhara H, and Einaga Y*
“A rapid and simple electrochemical detection of the free drug concentration in human serum using boron-doped diamond electrodes”
Analyst 2022 Vol. 147, pp. 4442-4449

Review Paper 11
Furukawa Y*
“A pathological link between dysregulated copper binding in Cu/Zn-superoxide dismutase and amyotrophic lateral sclerosis”
Journal of Clinical Biochemistry and Nutrition 2022 Vol. 71, pp. 73-77

This review summarizes the copper and zinc binding process of SOD1 in vivo, based upon which possible dysregulation of such metal binding processes is discussed as a pathomechanism of SOD1-related amyotrophic lateral sclerosis (ALS). Furthermore, a copper chaperone for SOD1, which is responsible for supplying a copper ion to SOD1 in vivo, is discussed as a potential target for developing ALS therapeutics.


Original Paper 49
Imamura Y, Okuzumi A, Yoshinaga S, Hiyama A, Furukawa Y, Miyasaka T, Hattori N, and Nukina N*
“Quantum-dot-labeled synuclein seed assay identifies drugs modulating the experimental prion-like transmission”
Communications Biology 2022 Vol. 5, 636

本論文は、貫名 信行 先生(同志社大学)のグループで進められている研究で、パーキンソン病などの原因タンパク質であるα-synucleinの線維が生体内でどのように伝播していくのかを理解するための研究で、その伝播を制御する薬剤に関する結果が報告されています。私たちは、本論文で用いられたα-synuclein線維の構造情報について、FT-IRなどを使って検討させていただきました。

Original Paper 48
Tajiri M, Aoki H, Shintani A, Sue K, Akashi S*, and Furukawa Y*
“Metal distribution in Cu/Zn-superoxide dismutase revealed by native mass spectrometry”
Free Radical Biology and Medicine 2022 Vol. 183, pp. 60-68


Original Paper 47
Kimura S, Kamishina H, Hirata Y, Furuta K, Furukawa Y, Yamato O, Maeda S, and Kamatari YO*
“Novel oxindole compounds inhibit the aggregation of amyloidogenic proteins associated with neurodegenerative diseases”
Biochimica et Biophysica Acta 2022 Vol.1866, 130114
Press Release from Gifu Univ.
Press Release from Keio Univ.


Original Paper 46
Furukawa Y*, Shintani A, Kokubo T
“A dual role of cysteine residues in the maturation of prokaryotic Cu/Zn-superoxide dismutase”
Metallomics 2021 Vol.13, mfab050

Previously, our group showed that the conserved disulfide bond of Cu/Zn-superoxide dismutase plays critical roles in the structural stabilization.  In our newly published study with E. coli Cu/Zn-superoxide dismutase (SodC), we have revealed that prior to the disulfide formation, the thiolates of the Cys residues can capture copper ions with extremely high affinity.  We hence suppose that the conserved Cys residues play a dual role: acquisition of a copper ion and formation of the disulfide bond.


Original Paper 45
Hirose M, Asano M, Watanabe-Matsumoto S, Yamanaka K, Abe Y, Yasui M, Tokuda E, Furukawa Y, and Misawa H*
“Stagnation of glymphatic interstitial fluid flow and delay in waste clearance in the SOD1-G93A mouse model of ALS”
Neuroscience Research 2020 Vol. 171, pp. 74-82

体の中で生じる老廃物を排せつ・処理するためにリンパ系が全身に張り巡らされていることはよく知られていますが、不思議なことに、脳や脊髄といった中枢神経系にはリンパ系が見つかっていませんでした。しかし、最近になって、中枢神経系に生じた老廃物は、脳脊髄液の流れを利用したシステム(脳リンパ流:glymphatic system)によって除去されることが提案されています。今回、薬学部の三澤教授は、脳リンパ流を発生させる水チャネルAQP4に着目し、AQP4をノックアウトすることで脳リンパ流の流れを悪くすると、変異型SOD1の凝集体(老廃物)が脳・脊髄から除去される効率が低下し、筋萎縮性側索硬化症(ALS)の発症につながるメカニズムを提唱しました。本研究は、慶應義塾大学次世代研究プロジェクトの支援を受けたもので、医学部の安井教授とともに、古川も変異型SOD1凝集体の提供・解析という面で協力させていただきました。

Review Paper 10
古川 良明*
生物物理 2020 Vol.60 pp.338-341


古川 良明*
Newsletter 日本化学会 生体機能関連化学部会 2020 Vol. 35, pp. 4-5

Review Paper 9
Furukawa Y*
“Good and bad of Cu/Zn-superoxide dismutase controlled by metal ions and disulfide bonds”
Chemistry Letters 2020 Vol. 50, pp. 331-341

This review summarizes intracellular processes for metal binding and disulfide formation in SOD1, both of which are essential to stabilization of the protein structure as well as its enzymatic function. Also, failure of those processes as a possible cause of a neurodegenerative disease through protein misfolding will be described.


Review Paper 8
Furukawa Y* and Tokuda E
“Does wild-type Cu/Zn-superoxide dismutase have pathogenic roles in amyotrophic lateral sclerosis?”
Translational Neurodegeneration 2020 Vol. 9 Article 33

Mutations in the gene coding Cu/Zn-superoxide dismutase (SOD1) have been detected in a part of familial forms of ALS, and abnormal accumulation of misfolded mutant SOD1 in affected spinal motor neurons has been established as a pathological hallmark of ALS caused by mutations in SOD1 (SOD1-ALS). Nonetheless, involvement of wild-type SOD1 remains quite controversial in the pathology of ALS with no SOD1 mutations (non-SOD1 ALS), which occupies more than 90% of total ALS cases. We reviewed pathological studies on mouse models and patients and then summarized arguments for and against possible involvement of wild-type SOD1 in non-SOD1 ALS as well as in SOD1-ALS.


Original Paper 44
Anzai I, Tokuda E, Handa S, Misawa H, Akiyama S, and Furukawa Y*
“Oxidative misfolding of Cu/Zn-superoxide dismutase triggered by non-canonical intramolecular disulfide formation”
Free Radical Biology and Medicine 2020 Vol. 147 pp.187-199
Press Release from Keio Univ.
Press Release from IMS

A dominant mutation in a gene coding Cu/Zn-superoxide dismutase (SOD1) is the first described genetic cause for familial ALS. SOD1-related ALS cases are characterized by abnormal accumulation of misfolded SOD1 proteins in motoneurons. Many researchers believe that elucidation of the SOD1 misfolding will contribute to the understanding of ALS pathogenesis; however, it still remains controversial how SOD1 misfolds in pathological conditions. In this study, a new mechanism of SOD1 misfolding has been proposed, which is characterized by the demetallation-triggered formation of a non-canonical intramolecular disulfide bond in oxidizing environment. The misfolded SOD1 with such a newly identified abnormal conformation was found to exhibit significant cytotoxicity as well as high propensity to aggregate. ALS patients are known to show marked elevation in several markers of oxidative damages; therefore, the oxidative misfolding of SOD1 we have proposed will be important in understanding the SOD1-related ALS pathomechanism.


Original Paper 43
Tokuda E, Takei Y, Ohara S, Fujiwara N, Hozumi I, and Furukawa Y*
“Wild-type Cu/Zn-superoxide dismutase is misfolded in cerebrospinal fluid of sporadic amyotrophic lateral sclerosis”
Molecular Neurodegeneration 2019 Vol.14 42
Press Release from Keio Univ.

There are currently no cures for the neurodegenerative disease ALS. In 1993, SOD1 was identified as a causative gene for familial ALS cases, and misfolded mutant SOD1 is known to abnormally accumulate in degenerating motor neurons. Nonetheless, SOD1 mutations are found in only 2% of total ALS cases. Because a pathogenic mutation is not a prerequisite for the misfolding of SOD1 in vitro, much effort has been made for the detection of misfolded wild-type SOD1 in ALS patients without SOD1 mutations. Here, we found for the first time that wild-type SOD1 was misfolded specifically in the cerebrospinal fluid (CSF) of sporadic ALS cases. More importantly, we showed that the misfolded wild-type SOD1 in the CSF was toxic to motor neuron-like cells. We thus believe that our manuscript will provide important insights into the development of therapeutics for sporadic ALS.


Original Paper 42
Tanaka G, Yamanaka T, Furukawa Y, Kajimura N, Mitsuoka K, and Nukina N*
“Sequence- and seed-structure-dependent polymorphic fibrils of alpha-synuclein”
Biochimica et Biophysica Acta – Molecular Basis of Disease 2019 Vol.1865 pp.1410-1420