Cytoskeletal Regulation of Erythrocyte Glucose Transporter-1

总结 红细胞血影蛋白-肌动蛋白连接在维持细胞形状和功能方面起着关键作用。 膜性能因此，它们的组织和膜连接是至关重要的 对红细胞生理学的重要性。我们最近的证据表明，dematin执行一个 通过将这些连接点连接到细胞膜来发挥中枢功能。在这里，我们建议， 通过将血影蛋白-肌动蛋白连接点连接到膜上来执行其生物学功能， 葡萄糖转运蛋白-1（GLUT 1）。我们将在以下条件下检验这一假设： 以下三个目的：A1：GLUT 1与人血影蛋白-肌动蛋白连接的相互作用 红细胞我们已经确定GLUT 1是dematin的主要膜受体， 内收蛋白。我们建议确定GLUT 1的相互作用域， dematin和内收蛋白，并通过生物化学手段破坏GLUT 1-细胞骨架桥， 评估其对人红细胞的膜稳定性和形状的影响。A2.德马廷 以及小鼠红细胞和脂肪细胞中的内收蛋白结合受体。我们建议 dematin和adducin与小鼠红细胞中的一种新的膜受体结合。我们将 使用免疫沉淀、质谱和化学交联鉴定该受体 测定。我们将测试dematin和adducin与几种潜在的膜的结合 在我们对小鼠红细胞膜囊泡的蛋白质组学筛选中鉴定的蛋白质。我们将 同时研究了dematin和adducin与GLUT 4的结合，并探讨了它们的功能 对脂肪细胞中GLUT 4再循环和葡萄糖摄取的影响。这些实验将阐明 小鼠红细胞中连接血影蛋白-肌动蛋白连接的替代受体的作用， 脂肪细胞A3.完全性地马丁缺乏的生理意义。最近我们 在dematin头部结构域缺失小鼠中观察到肥胖表型。阐明本 为了研究dematin头部结构域的特异性作用，我们提出了一种新的小鼠模型 使用常规基因靶向技术治疗完全dematin缺乏的患者。我们将 比较headpiece和dematin敲除小鼠的贫血和肥胖表型， 特别是受损的GLUT 4运输和糖尿病。总之，这些研究很可能 揭示了dematin，内收蛋白和葡萄糖转运蛋白在贫血调节中的新功能 和代谢性疾病，对其他含有头片段结构域的 proteins.

SUMMARY Erythrocyte spectrin-actin junctions play a critical role in the maintenance of cell shape and membrane properties. Their organization and membrane linkage is therefore of fundamental importance to erythrocyte physiology. Our recent evidence indicates that dematin performs a pivotal function by linking these junctions to the membrane. Here, we propose that dematin performs its biological function by linking the spectrin-actin junctions to the membrane via glucose transporter-1 (GLUT1) in human erythrocytes. We will test this hypothesis under the following three aims: A1: GLUT1 interaction with the spectrin-actin junctions in human erythrocytes. We have identified GLUT1 as the primary membrane receptor for dematin and adducin in human erythrocytes. We propose to identify the interacting domains of GLUT1, dematin, and adducin, and disrupt the GLUT1-cytoskeletal bridge by biochemical means, thus assessing its impact on the membrane stability and shape of human erythrocytes. A2. Dematin and adducin binding receptor(s) in mouse erythrocytes and adipocytes. We propose that dematin and adducin bind to a novel membrane receptor(s) in mouse erythrocytes. We will identify this receptor using immunoprecipitation, mass spectrometry, and chemical crosslinking assays. We will test the binding of dematin and adducin with several potential membrane proteins identified in our proteomics screen of mouse erythrocyte membrane vesicles. We will also investigate the binding of dematin and adducin with GLUT4, and investigate their functional effects on GLUT4 recycling and glucose uptake in adipocytes. These experiments will clarify the role of alternate receptors that link the spectrin-actin junctions in mouse erythrocytes and adipocytes. A3. Physiological implications of complete dematin deficiency. Recently, we observed an obesity phenotype in the dematin headpiece domain null mice. To elucidate the specific role of the headpiece domain of dematin, we propose to generate a new mouse model with complete dematin deficiency using the conventional gene targeting techniques. We will compare the anemia and obesity phenotypes in the headpiece and dematin null mice focusing particularly on the impaired GLUT4 trafficking and diabetes. Together, these studies are likely to unveil a novel function of dematin, adducin, and glucose transporters in the regulation of anemia and metabolic disorders with broader implications for other headpiece domain-containing proteins.