研究者詳細 - 佐藤　ちひろ

Hypoxic culture induces expression of Sialin, a sialic acid transporter, and cancer-associated gangliosides containing non-human sialic acid on human cancer cells. , 査読有り Open Access

Yin, J., Hashimoto, A., Izawa, M., Miyazaki, K., Chen G-Y., Takematsu, H., Kozutsumi, Y., Suzuki, A., Furuhata, K., Cheng, F.-L. Lin, C.-H., Sato, C., Kitajima, K., and Kannagi, R.

Cancer Res. 66 巻頁： 2937-2945 2006年

Flagellasialin: a novel sulfated alpha2,9-linked polysialic acid glycoprotein of sea urchin sperm flagella. 査読有り Open Access

Miyata S, Sato C, Kumita H, Toriyama M, Vacquier VD, Kitajima K.

Glycobiology 16 巻頁： 1229-12241 2006年

記述言語：英語掲載種別：研究論文（学術雑誌）

A novel α2,9-linked polysialic acid-containing glycoprotein of sea urchin sperm flagella was previously identified and named “flagellasialin". Flagellasialin from Hemicentrotus pulcherrimus shows a diverse relative molecular mass on SDS-PAGE of 40-80 kDa. Its glycan structures were determined as HSO3→8Neu5Acα2→9(Neu5Acα2→9)n-2Neu5Acα2→6GalNAcα1→Thr (n, averaging 15) [Miyata et al. (2004) Glycobiology, 14, 827-840]. In this study, we purified flagellasialin, and cloned its cDNA. Flagellasialin is a 96-amino acid, threonine-rich, heavily O-glycosylated (80-90% by weight) glycoprotein with a single transmembrane segment at its C-terminus and no apparent cytosolic domain. Of 12 extracellular Thr residues, eight are O-glycosylated and three are non-glycosylated. Flagellasialin is highly expressed in testis, but cannot be detected in ovary. The amino acid sequences of flagellasialin from three sea urchin species (H. pulcherrimus, Strongylocentrotus purpuratus and S. franciscanus) are identical, but some species differences exist in the three core glycan structures to which the sulfated α2,9-linked polyNeu5Ac chain is linked. Finally, a specific antibody against the α2,9-linked polyNeu5Ac structure inhibits sperm motility and reduces fertilization, implicating flagellasialin as a regulator of these critical processes.

DOI： 10.1093/glycob/cwl036

*Identification of disialic acid-containing glycoproteins in mouse serum. 査読有り

Yasukawa, Z., Sato, C., Sano, K., Ogawa, H. and Kitajima, K.

Glycobiology 15 巻頁： 827-837 2006年

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）

Serum glycoproteins are involved in various biological activities such as removal of exogenous antigen, fibrinolysis, transport of metal. They are also useful markers of inflammation and diseases. Although it is known that the amount of sialic acid increases after inflammation, little attention has been paid to the presence of linkage specific epitope in serum,especially, the α2,8-linkage. In the previous study, we demonstrated that four components in mouse serum contain the α2,8-linked disialic acid, based on the immunoreactivity with mAb.2-4B that is specific to Neu5Gcα2→(8Neu5Gcα2→)n-1, n≥2 (Yasukawa, Z. et al. (2005) Glycobiology 15, 827-837). In this study, we purified three components, 30kDa-gp, 70kDa-gp, and 120kDa-gp and identified as the light chain of immunoglobulins, vitronectin, and plasminogen, respectively, using MALDI-TOF MS analyses. The modifications of these proteins with the α2,8-linked disialic acid was chemically confirmed by fluorometric C7/C9 analyses and acid hydrolysates-DMB methods. We also showed that the light chains of IgG, IgM and IgE are commonly modified with the α2,8-linked disialic acid. In addition, not only mouse vitronectin but also rat vitronectin was also modified with disialic acid and the amount of disialylation on vitronectin decreased after hepatectomy. These results indicate that disialic acid-modification on serum glycoprotein has some biological meanings in immunological events and fibrinolysis.

Involvement of the alpha2,8-polysialyltransferases II/STX and IV/PST in the biosynthesis of polysialic acid chains on the O-linked glycoproteins in rainbow trout ovary. 査読有り

Asahina S, Sato C, Matsuno M, Matsuda T, Colley K, Kitajima K. Asahina S, Sato C, Matsuno M, Matsuda T, Colley K, Kitajima K.

J Biochem. 140 巻頁： 687-701 2006年

Oral ingestion of mannose alters the expression level of deaminoneuraminic acid (KDN) in mouse organs. 査読有り

Go, S., Sato, C., and Kitajima, K.

Glycoconjugate J. 23 巻頁： 411-421 2006年

Weaning-induced expression of a milk-fat globule protein, MFG-E8, in mouse mammary glands, as demonstrated by the analyses of its mRNA, protein and phosphatidylserine-binding activity. 査読有り Open Access

Nakatani H, Aoki N, Nakagawa Y, Jin-No S, Aoyama K, Oshima K, Ohira S, Sato C, Nadano D, Matsuda T.

Biochem J. 395 巻頁： 21-30 2006年

Nakatani H, Aoki N, Nakagawa Y, Jin-No S, Aoyama K, Oshima K, Ohira S, Sato C, Nadano D, Matsuda T

Biochem J. 395 巻頁： 21-30 2006年

Hypoxic culture induces expression of Sialin, a sialic acid transporter, and cancer-associated gangliosides containing non-human sialic acid on human cancer cells. , 査読有り Open Access

Yin, J, Hashimoto, A, Izawa, M, Miyazaki, K, Chen G-Y, Takematsu, H, Kozutsumi, Y, Suzuki, A, Furuhata, K, Cheng, F.-L. Lin, C.-H, Sato, C, Kitajima, K, Kannagi, R

Cancer Res. 66 巻頁： 2937-2945 2006年

Oral ingestion of mannose alters the expression level of deaminoneuraminic acid (KDN) in mouse organs. 査読有り

Go, S, Sato, C, Kitajima, K

Glycoconjugate J. 23 巻頁： 411-421 2006年

Involvement of the alpha2,8-polysialyltransferases II/STX and IV/PST in the biosynthesis of polysialic acid chains on the O-linked glycoproteins in rainbow trout ovary. 査読有り

Asahina S, Sato C, Matsuno M, Matsuda T, Colley K, Kitajima, K, Asahina S, Sato C, Matsuno M, Matsuda T, Colley K, Kitajima K

J Biochem. 140 巻頁： 687-701 2006年

Inflammation-dependent changes in alpha2,3-, alpha2,6-, and alpha2,8-sialic acid glycotopes on serum glycoproteins in mice. 査読有り Open Access

Yasukawa Z, Sato C, Kitajima K

Glycobiology 15 巻 ( 9 ) 頁： 827 - 37 2005年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Glycobiology

The expression of acute-phase serum proteins increases in response to inflammatory stimuli. Most of these proteins are glycoproteins that often contain sialic acids (Sia). It is unknown, however, how the expression of Sia in these glycoproteins changes during inflammation. This study demonstrates changes in the α2,3-, α2,6-, and α2,8-Sia glycotopes on serum glycoproteins in response to turpentine oil-induced inflammation, based on lectin- and immunoblot analyses by using sialyl linkage-specific lectins, Maackia amurensis for the α2,3-Sia glycotope and Sambucus sieboldiana for the α2,6-Sia glycotopes, and monoclonal antibody 2-4B (mAb.2-4B) recognizing the di- and oligomers of the α2,8-Neu5Gc residue. There was an increase in a limited number of sialoglycoproteins containing the α2,3-, α2,6-, or α2,8-Sia glycotopes. Reverse transcription-polymerase chain reaction (RT-PCR) analysis of the expression profiles of mRNAs for the known sialyltransferases in mouse liver during inflammation indicated the up-regulated expression of β-galactoside α2,3-sialyltransferases (ST3Gal I and ST3Gal III) and β-N-acetylgalactosaminide α2,6-sialyltransferase (ST6GalNAc VI) as well as β-galactoside α2,6-sialyltransferase (ST6Gal I) mRNAs. Notably, ST3Gal I and III and ST6GalNAc VI are involved in the synthesis of the α2,3- and α2,6-Sia glycotopes on O-glycan chains and possibly on gangliosides, whereas ST6Gal I is specific for N-glycan chains. These results provide evidence for the inflammation-induced expression of sialyl glycotopes in serum glycoproteins. We demonstrated that inflammation significantly increased the expression of an unknown 32-kDa glycoprotein containing the α2,8-Sia glycotope. The mechanism for the increase in glycoprotein in inflamed mouse serum remains to be examined, as mRNA expression for all of the α2,8-sialyltransferases (ST8Sia I-VI) was unchanged during inflammation. © The Author 2005. Published by Oxford University Press. All right reserved.

DOI： 10.1093/glycob/cwi068

Crystallization and preliminary X-ray analysis of mitochondrial presequence receptor Tom20 in complexes with a presequence from aldehyde dehydrogenase Open Access

Igura M, Ose T, Obita T, Sato C, Maenaka K, Endo T, Kohda D

ACTA CRYSTALLOGRAPHICA SECTION F-STRUCTURAL BIOLOGY COMMUNICATIONS 61 巻 ( 5 ) 頁： 514-517 2005年5月

Distal myopathy with rimmed vacuoles - Impaired O-glycan formation in muscular glycoproteins Open Access

Tajima Y, Uyama E, Go S, Sato C, Tao N, Kotani M, Hino H, Suzuki A, Sanai Y, Kitajima K, Sakuraba H

AMERICAN JOURNAL OF PATHOLOGY 166 巻 ( 4 ) 頁： 1121-1130 2005年4月

Distal myopathy with rimmed vacuoles: impaired O-glycan formation in muscular glycoproteins. 査読有り Open Access

Tajima Y, Uyama E, Go S, Sato C, Tao N, Kotani M, Hino H, Suzuki A, Sanai Y, Kitajima K, Sakuraba H

The American journal of pathology 166 巻 ( 4 ) 頁： 1121 - 30 2005年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：American Journal of Pathology

Distal myopathy with rimmed vacuoles (DMRV), is an autosomal recessive disorder with early adult onset, displays distal dominant muscular involvement and is characterized by the presence of numerous rimmed vacuoles in the affected muscle fibers. The pathophysiology of DMRV has not been clarified yet, although the responsible gene was identified as that encoding UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase involved hi the biosynthesis of sialic acids. To identify defective carbohydrate moieties of muscular glycoproteins from DMRV patients, frozen skeletal muscle sections from seven patients with DMRV, as well as normal and pathological controls, were treated with or without sialidase or N-glycosidase F followed by lectin staining and lectin blotting analysis. The sialic acid contents of the O-glycans in the skeletal muscle specimens from the DMRV patients were also measured. We found that Arachis hypogaea agglutinin (PNA) lectin reacted strongly with sarcolemmal glycoproteins in the DMRV patients but not with those in control subjects. α-Dystroglycan from the DMRV patients strongly associated with PNA lectin, although that from controls did not. The sialic acid level of the O-glycans in the DMRV muscular glycoproteins with molecular weights of 30 to 200 kd was reduced to 60 to 80% of the control level. The results show that impaired sialyl O-glycan formation in muscular glycoproteins, including α-dystroglycan, occurs in DMRV.

DOI： 10.1016/S0002-9440(10)62332-2

Differentiation of noncancerous tissue and cancer lesions by apparent diffusion coefficient values in transition and peripheral zones of the prostate Open Access

Sato C, Naganawa S, Nakamura T, Kumada H, Miura S, Takizawa O, Ishigaki T

JOURNAL OF MAGNETIC RESONANCE IMAGING 21 巻 ( 3 ) 頁： 258-262 2005年3月

Development of a simple and efficient method for assaying cytidine monophosphate sialic acid synthetase activity using an enzymatic reduced nicotinamide adenine dinucleotide/oxidized nicotinamide adenine dinucleotide converting system. 査読有り

Fujita A, Sato C, Münster-Kühnel AK, Gerardy-Schahn R, Kitajima K

Analytical biochemistry 337 巻 ( 1 ) 頁： 12 - 21 2005年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Analytical Biochemistry

A new reliable method to assay the activity of cytidine monophosphate sialic acid (CMP-Sia) synthetase (CSS) has been developed. The activation of sialic acids (Sia) to CMP-Sia is a prerequisite for the de novo synthesis of sialoglycoconjugates. In vertebrates, CSS has been cloned from human, mouse, and rainbow trout, and the crystal structure has been resolved for the mouse enzyme. The mouse and rainbow trout enzyme have been compared with respect to substrate specificity, demonstrating that the mouse enzyme exhibits a pronounced specificity for N-acetylneuraminic acid (Neu5Ac), while the rainbow trout CSS is equally active with either of three Sia species, Neu5Ac, N-glycolylneuraminic acid (Neu5Gc), and deaminoneuraminic acid (KDN). However, molecular details that explain the pronounced substrate specificities are unknown. Understanding the catalytic mechanisms of these enzymes is of major importance, since CSSs play crucial roles in cellular sialylation patterns and thus are potential drug targets in a number of pathophysiological situations. The availability of the cDNAs and the obtained structural data enable rational approaches; however, these efforts are limited by the lack of a reliable high-throughput assay system. Here we describe a new assay system that allows product quantification in a reduced nicotinamide adenine dinucleotide (NADH)-dependent color reaction. The activation reaction catalyzed by CSS, CTP + Sia → CMP-Sia + pyrophosphate, was evaluated by a consumption of Sia, which corresponds to that of NADH on the following two successive reactions: (i) Sia → pyruvate + ManNAc (or Man), catalyzed by a sialic acid lyase (SAL), and (ii) pyruvate + NADH → lactate + oxidized nicotinamide adenine dinucleotide (NAD +), catalyzed by a lactate dehydrogenase (LDH). Consumption of NADH can be photometrically monitored on a microtiter plate reader for a number of test samples at the same time. Furthermore, based on the quantification of CSS used in the SAL/LDH assay, relative activities toward Sia derivatives have been obtained. The preference of mouse CSS toward Neu5Ac and the ability of the rainbow trout enzyme to activate both KDN and Neu5Ac were confirmed. Thus, this simple and time-saving method is suitable for a systematic comparison of enzyme activity of structurally mutated enzymes based on the relative specific activity. © 2004 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.ab.2004.10.033