0-glycoprotein podoplanin in vascular development

0-糖蛋白足足蛋白在血管发育中的作用

• 批准号: 8853325
• 负责人: RODGER PAUL MCEVER
• 金额: $ 46.31万
• 依托单位: OKLAHOMA MEDICAL RESEARCH FOUNDATION
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至 2017-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8853325
• 关键词: Address; Affect; Alveolar; Amino Acids; Binding; Biology; Biotinylation; Blood; Blood Circulation; Blood Platelets; Blood Vessels; Cell Survival; Cell surface; Cells; Collaborations; Cytoplasmic Tail; Data; Development; Doxycycline; Embryo; Embryonic Development; Employee Strikes; Endothelial Cells; Epithelial Cells; Epitopes; Event; Extracellular Domain; Galactose; Genetic Models; Glycobiology; Glycoproteins; Golgi Apparatus; Homeostasis; Human; Immune response; Immunofluorescence Immunologic; Implant; Label; Lead; Lectin; Link; Lipids; Location; Lymphangiogenesis; Lymphatic; Lymphatic Abnormalities; Lymphatic Endothelial Cells; Lymphatic System; Lymphatic vessel; Lymphoma; Maintenance; Mediating; Membrane; Metabolic; Molecular Weight; Mucins; Mus; Myeloid Cells; Neoplasm Metastasis; Osteoblasts; Pathologic Processes; Phenotype; Physiologic pulse; Play; Polysaccharides; Post-Translational Protein Processing; Process; Proteins; Publishing; Reaction; Recombinants; Rodent; Role; Serine; Sialic Acids; Signal Transduction; Site; Sorting - Cell Movement; Structure; System; Tail; Tamoxifen; Testing; Threonine; Tissues; Tn antigen; Transmembrane Domain; Vascular Endothelial Cell; Vascular System; absorption; base; cancer type; cell type; ezrin; glycosylation; glycosyltransferase; in vivo; insight; lymphatic circulation; melanoma; member; migration; moesin; mutant mouse model; neoplastic cell; novel; podocyte; podoplanin; postnatal; radixin protein; receptor; sialylation; trafficking; transdifferentiation; tumor; tumor growth

Podoplanin (Pdpn) is a type 1 transmembrane mucin-type O-glycoprotein [1, 2]. It consists of 172 amino acids in mice and 163 amino acids in humans. It is expressed in lymphafic endothelial cells (LECs) as well as many other cell types including alveolar type I epithelial cells, podocytes, osteoblast cells, and several tumor cell types [1-4]. Hence, it is also known as Tia, OTS-8, gp36 and Aggrus, based on the cell type in which it has been identified [2, 5-8]. Pdpn has an extracellular domain, a single transmembrane domain, and a short cytoplasmic tail (Fig. 1 A). It is highly consen/ed between rodents and humans (Fig. 1 A). Protein homology is particulariy evident in the cytoplasmic carboxy-terminal tail of Pdpn, suggesfing important functions. Indeed, the cytoplasmic domain of Pdpn has been shown to interact with members ofthe ERM (ezrin, radixin, moesin) proteins in epithelial cells, and to subsequently activate RhoA and promote cell transdifferentiation [9]. A striking feature of the extracellular domain of Pdpn is a high content of serine and threonine residues that could potenfially be O-glycosylated [10,11] (Fig. IA). Mucin-type O-glycosylation is a prevalent form of post-translational modification of membrane and secreted proteins [12-15]. It occurs in the Golgi apparatus via sequential reactions catalyzed by specific glycosyltransferases (Fig. IB). The core of all mucin-type O-glycans is serine/threonine-linked Nacetylgalactosamine (GalNAcal-Ser/Thr), also known as Tn antigen, which is normally further modified to form distinct subtypes of Oglycans. Among them, core 1 O-glycans are a predominant form. Core 1 O-glycans are synthesized by adding galactose (Gal) to Tn antigen, a reaction catalyzed solely by the T-synthase (core 1 synthase, Cigaltl) [13-16). Core 1 structure can be further branched to form extended core 1, core 2 structures, or can be modified by adding sialic acids. These glycans are known as core 1-derived O-glycans [15,16]. Core 1-derived O-glycans are present in most cell types, especially in epithelial cells and endothelial cells [15]. Altered O-glycosylafion can affect numerous processes such as glycoprotein conformafion, trafficking, sorting, or degradafion [14,17,18]. Moreover, the O-glycosylafion state of glycoproteins may also dictate changes in cell-cell interacfions and/or cell signaling [19]. The extracellular domain of mouse Pdpn contains 24 potential sites of O-glycosylafion (Fig. 1A). The molecular weight of core Pdpn protein is about 17 kDa, however, Pdpn isolated from different tissues has molecular weight ranging from 37 to 41 kDa, suggesting extensive O-glycosylafion. Our recent study provides the first evidence in vivo that O-glycosylation is essential for fhe cell surface expression of Pdpn [14], although how O-glycosylafion regulates Pdpn expression/funcfion remains to be determined. Our study also revealed a critical contribution of core 1-derived O-glycans and Pdpn to lymphatic vascular development.

Podoplanin（Pdpn）是一种1型跨膜粘蛋白型O-糖蛋白[1，2]。它由172个氨基酸在小鼠和163个氨基酸在人类。它在血管内皮细胞（LEC）以及许多其他细胞类型中表达，包括肺泡I型上皮细胞、足细胞、成骨细胞和几种肿瘤细胞。 细胞类型[1-4]。因此，基于其已被鉴定的细胞类型，其也被称为Tia、OTS-8、gp 36和聚集蛋白[2，5-8]。Pdpn具有胞外结构域、单个跨膜结构域和短的胞质尾区（图1A）。它在啮齿动物和人类之间高度一致/艾德（图1A）。蛋白质同源性是 在Pdpn的胞质羧基末端尾中特别明显，具有重要的功能。事实上，Pdpn的胞质结构域已显示与上皮细胞中的ERM（埃兹蛋白、根蛋白、膜突蛋白）蛋白的成员相互作用，并且随后激活RhoA并促进细胞转分化[9]。 Pdpn的胞外结构域的显著特征是高含量的丝氨酸， 苏氨酸残基可能潜在地被O-糖基化[10，11]（图1A）。粘蛋白型0-糖基化是膜和分泌蛋白的翻译后修饰的普遍形式[12-15]。 它通过由特定糖基转移酶催化的顺序反应发生在高尔基体中（图1B）。所有粘蛋白型O-聚糖的核心是 丝氨酸/苏氨酸连接的N乙酰半乳糖胺（GalNAcal-Ser/Thr），也 称为Tn抗原，其通常被进一步修饰以形成不同的O聚糖亚型。 其中，核心10-聚糖是主要形式。通过将半乳糖（Gal）添加至Tn抗原来合成核心10-聚糖，该反应仅由T-合酶（核心1合酶，Gal 1）催化[13-16）。核心1结构可以进一步分支以形成延伸的核心1、核心2结构，或者可以通过以下方式改性： 加入唾液酸。这些聚糖被称为核心1衍生的O-聚糖[15，16]。 核心1衍生的O-聚糖存在于大多数细胞类型中，特别是上皮细胞和内皮细胞中[15]。改变的O-糖基化可影响许多过程，如糖蛋白构象、运输、分选或降解[14，17，18]。此外，糖蛋白的O-糖基化状态也可能决定细胞-细胞相互作用和/或细胞信号传导的变化[19]。 小鼠Pdpn的胞外结构域含有24个潜在的O-糖基化位点（图1A）。Pdpn核心蛋白的分子量约为17 kDa，而从不同组织中分离到的Pdpn分子量在37 ~ 41 kDa之间，表明存在广泛的O-糖基化。我们最近的研究提供了 第一个体内证据表明O-糖基化对于Pdpn的细胞表面表达是必需的[14]，尽管O-糖基化如何调节Pdpn的表达/功能仍有待确定。我们的研究还显示， 核心1衍生的O-聚糖和Pdpn对淋巴管发育的关键贡献。