Branched Sialylated N-glycans Are Accumulated in Brain Synaptosomes and Interact with Siglec-H

Cell Structure and Function

Katsunori Tanaka¹  Hiroyuki Konishi²  Yuko Fukata³  Takeshi Yoshimura⁴  Yoshiyuki Manabe⁵  Mai Handa-Narumi⁶ 

[1] Department of Chemistry, Graduate School of Science, Osaka University;Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University;Department of Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine;Department of Physiological Sciences, School of Life Sciences, SOKENDAI (The Graduate University for Advanced Studies);Division of Membrane Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences;Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, National Institutes of Natural Sciences

关键词: N-glycan;    subcellular fractionation;    calreticulin;    dendritic spine;    Siglec-H;   

DOI  :  10.1247/csf.18009

学科分类：分子生物学，细胞生物学和基因

来源: Japan Society for Cell Biology

【 摘 要 】

Proper N-glycosylation of proteins is important for normal brain development and nervous system function. Identification of the localization, carrier proteins and interacting partners of N-glycans is essential for understanding the roles of glycoproteins. The present study examined the N-glycan A2G'2F (Galβ1-3GlcNAcβ1-2Manα1-6[Galβ1-3GlcNAcβ1-2Manα1-3]Manβ1-4GlcNAcβ1-4[Fucα1-6]GlcNAc-). A2G'2F has a branched sialic acid structural feature, and branched sialylated A2G'2F is a major N-glycan in the mouse brain. Its expression in the mouse brain increases during development, suggesting that branched sialylated N-glycans play essential roles during brain development. However, the carrier proteins, interacting partners and localization of branched sialylated N-glycans remain unknown. We previously improved our method for analyzing N-glycans from trace samples, and here we succeeded in detecting A2G'2F in small fragments excised from the two-dimensional electrophoresis gels of subcellular fractionated mouse brain proteins. A2G'2F was accumulated in mouse brain synaptosomes. We identified calreticulin as one of the candidate A2G'2F carriers and found calreticulin expression in both the endoplasmic reticulum and synaptosomal fractions. Calreticulin was observed in dendritic spines of cultured cortical neurons. Synthesized branched sialylated glycan clusters interacted with sialic acid-binding immunoglobulin-like lectin H (Siglec-H), which is known to be a microglia-specific molecule. Taken together, these results suggest that branched sialylated A2G'2F in synaptosomes plays a role in the interaction of dendritic spines with microglia.

【 授权许可】

Unknown