Tamao Endo

Bio: Tamao Endo is an academic researcher from Kyoto University. The author has contributed to research in topics: Glycosylation & Glycan. The author has an hindex of 38, co-authored 126 publications receiving 5146 citations.

Demonstration of mammalian protein O-mannosyltransferase activity: coexpression of POMT1 and POMT2 required for enzymatic activity.

Abstract: Defects in O-mannosylation of α-dystroglycan are thought to cause certain types of congenital muscular dystrophies with neuronal migration disorders. Among these muscular dystrophies, Walker–Warburg syndrome is caused by mutations in the gene encoding putative protein O-mannosyltransferase 1 (POMT1), which is homologous to yeast protein O-mannosyltransferases. However, there is no evidence that POMT1 has enzymatic activity. In this study, we first developed a method to detect protein O-mannosyltransferase activity in mammalian cells. Then, using this method, we showed that coexpression of both POMT1 and POMT2 (another gene homologous to yeast protein O-mannosyltransferases) was necessary for the enzyme activity, but expression of either POMT1 or POMT2 alone was insufficient. The requirement of an active enzyme complex of POMT1 and POMT2 suggests that the regulation of protein O-mannosylation is complex. Further, protein O-mannosylation appears to be required for normal structure and function of α-dystroglycan in muscle and brain. In view of the potential importance of this form of glycosylation for a number of developmental and neurobiological processes, the ability to assay mammalian protein O-mannosyltransferase activity should greatly facilitate progress in the identification and localization of O-mannosylated proteins and the elucidation of their functional roles.

Proteomic analysis of two types of exosomes in human whole saliva.

Abstract: Saliva contains a large number of proteins that participate in the protection of oral tissue. Exosomes are small vesicles (30—100 nm in diameter) with an endosome-derived limiting membrane that are secreted by a diverse range of cell types. We have recently demonstrated that exosomes are present in human whole saliva. In this study, we found that whole saliva contained at least two types of exosomes (exosome I and exosome II) that are different in size and protein composition. Proteomic analysis revealed that both types of exosomes contained Alix, Tsg101 and Hsp70, all exosomal markers, immunoglobulin A and polymeric immunoglobulin receptor, whereas they had different protein compositions. Most of dipeptidyl peptidase IV known as CD26 in whole saliva, was present on the exosome II and metabolically active in cleaving chemokines (CXCL11 and CXCL12). Human whole saliva exosomes might participate in the catabolism of bioactive peptides and play a regulatory role in local immune defense in the oral cavity.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Extracellular vesicles: exosomes, microvesicles, and friends.

Abstract: Cells release into the extracellular environment diverse types of membrane vesicles of endosomal and plasma membrane origin called exosomes and microvesicles, respectively. These extracellular vesicles (EVs) represent an important mode of intercellular communication by serving as vehicles for transfer between cells of membrane and cytosolic proteins, lipids, and RNA. Deficiencies in our knowledge of the molecular mechanisms for EV formation and lack of methods to interfere with the packaging of cargo or with vesicle release, however, still hamper identification of their physiological relevance in vivo. In this review, we focus on the characterization of EVs and on currently proposed mechanisms for their formation, targeting, and function.

Biological properties of extracellular vesicles and their physiological functions

Abstract: In the past decade, extracellular vesicles (EVs) have been recognized as potent vehicles of intercellular communication, both in prokaryotes and eukaryotes. This is due to their capacity to transfer proteins, lipids and nucleic acids, thereby influencing various physiological and pathological functions of both recipient and parent cells. While intensive investigation has targeted the role of EVs in different pathological processes, for example, in cancer and autoimmune diseases, the EV-mediated maintenance of homeostasis and the regulation of physiological functions have remained less explored. Here, we provide a comprehensive overview of the current understanding of the physiological roles of EVs, which has been written by crowd-sourcing, drawing on the unique EV expertise of academia-based scientists, clinicians and industry based in 27 European countries, the United States and Australia. This review is intended to be of relevance to both researchers already working on EV biology and to newcomers who will encounter this universal cell biological system. Therefore, here we address the molecular contents and functions of EVs in various tissues and body fluids from cell systems to organs. We also review the physiological mechanisms of EVs in bacteria, lower eukaryotes and plants to highlight the functional uniformity of this emerging communication system.

Glycosylation in cancer: mechanisms and clinical implications

Abstract: Despite recent progress in understanding the cancer genome, there is still a relative delay in understanding the full aspects of the glycome and glycoproteome of cancer. Glycobiology has been instrumental in relevant discoveries in various biological and medical fields, and has contributed to the deciphering of several human diseases. Glycans are involved in fundamental molecular and cell biology processes occurring in cancer, such as cell signalling and communication, tumour cell dissociation and invasion, cell-matrix interactions, tumour angiogenesis, immune modulation and metastasis formation. The roles of glycans in cancer have been highlighted by the fact that alterations in glycosylation regulate the development and progression of cancer, serving as important biomarkers and providing a set of specific targets for therapeutic intervention. This Review discusses the role of glycans in fundamental mechanisms controlling cancer development and progression, and their applications in oncology.