Itoh Kazuyoshi, Nishihara Shoko
Glycan & Life Systems Integration Center (GaLSIC), Soka University, Hachioji, Japan.
Department of Biosciences, Graduate School of Science and Engineering, Soka University, Hachioji, Japan.
Front Neuroanat. 2021 Oct 18;15:767126. doi: 10.3389/fnana.2021.767126. eCollection 2021.
Mucin-type -glycosylation, a predominant type of -glycosylation, is an evolutionarily conserved posttranslational modification in animals. Mucin-type -glycans are often found on mucins in the mucous membranes of the digestive tract. These glycan structures are also expressed in other cell types, such as blood cells and nephrocytes, and have crucial physiological functions. Altered expression of mucin-type -glycans is known to be associated with several human disorders, including Tn syndrome and cancer; however, the physiological roles of mucin-type -glycans in the mammalian brain remains largely unknown. The functions of mucin-type -glycans have been studied in the fruit fly, . The basic structures of mucin-type -glycans, including Tn antigen (GalNAcα1-Ser/Thr) and T antigen (Galβ1-3GalNAcα1-Ser/Thr), as well as the glycosyltransferases that synthesize them, are conserved between and mammals. These mucin-type -glycans are expressed in the nervous system, including the central nervous system (CNS) and neuromuscular junctions (NMJs). In primary cultured neurons of , mucin-type -glycans show a characteristic localization pattern in axons. Phenotypic analyses using mutants of glycosyltransferase genes have revealed that mucin-type -glycans are required for CNS development, NMJ morphogenesis, and synaptic functions of NMJs in . In this review, we describe the roles of mucin-type -glycans in the nervous system. These findings will provide insight into the functions of mucin-type -glycans in the mammalian brain.
粘蛋白型O-糖基化是O-糖基化的主要类型，是动物中一种进化保守的翻译后修饰。粘蛋白型O-聚糖常见于消化道粘膜中的粘蛋白上。这些聚糖结构也在其他细胞类型中表达，如血细胞和肾细胞，并具有关键的生理功能。已知粘蛋白型O-聚糖的表达改变与多种人类疾病有关，包括Tn综合征和癌症；然而，粘蛋白型O-聚糖在哺乳动物大脑中的生理作用仍 largely unknown。已在果蝇中研究了粘蛋白型O-聚糖的功能。粘蛋白型O-聚糖的基本结构，包括Tn抗原（GalNAcα1-Ser/Thr）和T抗原（Galβ1-3GalNAcα1-Ser/Thr），以及合成它们的糖基转移酶，在果蝇和哺乳动物之间是保守的。这些粘蛋白型O-聚糖在果蝇的神经系统中表达，包括中枢神经系统（CNS）和神经肌肉接头（NMJ）。在果蝇的原代培养神经元中，粘蛋白型O-聚糖在轴突中呈现出特征性的定位模式。使用糖基转移酶基因突变体进行的表型分析表明，粘蛋白型O-聚糖是果蝇中枢神经系统发育、神经肌肉接头形态发生和神经肌肉接头突触功能所必需的。在本综述中，我们描述了粘蛋白型O-聚糖在果蝇神经系统中的作用。这些发现将为深入了解粘蛋白型O-聚糖在哺乳动物大脑中的功能提供线索。
