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2018 | Buch

Study of the Calcium Regulation Mechanism of TCR Activation Using Nanodisc and NMR Technologies

verfasst von: Yunchen Bi

Verlag: Springer Berlin Heidelberg

Buchreihe : Springer Theses

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SUCHEN

Über dieses Buch

This thesis describes the use of biophysical and biochemical methods to prove that calcium has a positive feedback effect on amplifying and sustaining CD3 phosphorylation and should enhance T-cell sensitivity to foreign antigens. The study presented shows that calcium can regulate the signal pathway in cells not only as a secondary messenger but also through direct interactions with the phospholipid bilayer. The approach used in the thesis also represents an important advance, as it couples the use of nuclear magnetic resonance (NMR) to the analysis of signaling phenomena in living cells. Moreover, the thesis optimizes the Nanodisc assembly protocol, which can broaden its range of applications in membrane protein studies. A preliminary study on the structure of dengue virus NS2B-NS3p in complex with aprotinin, which may help to develop new drugs against the dengue virus, is also included.

Inhaltsverzeichnis

Frontmatter
Chapter 1. Introduction
Abstract
A hurricane is being influenced by minor perturbations such as the flapping of the wings of a distant butterfly. The cell is the basic structural and functional unit of living systems, but how cell orchestrates its responses to stimuli from the intracellular or extracellular environment remains a fundamental question in biology. A tiny variation in these environments will elicit a series of biochemical events known as the cascade reactions inside the cell through signal transduction pathways. The consequences of such cascade reactions depend on cell type and can lead to changes in metabolism, gene or protein expression, morphology and cell cycle regulation. The interior and exterior environments of the cell are separated by the cell membrane, a lipid bilayer composed mainly of phospholipids and embedded proteins. The intracellular environment, termed the cytoplasm, is bounded by this membrane and consists of the cytosol and the cell’s organelles, which house the most important biochemical functions of the cell. However, many of the signaling molecules that mediate signal transduction pathways are located at the extracellular domain of the cell membrane and are excluded from the cytoplasm by this barrier. Like intracellular signal transduction, transmembrane signal transduction plays a key role in cell living process and must rely on these external molecules. This thesis discusses the transmembrane signal transduction study, using the calcium modulated T cell receptor (TCR) activity as a model.
Yunchen Bi
Chapter 2. Lipid Molecular-Ion Interaction Study Based on Nanodisc
Abstract
Reconstituting the membrane protein into a suitable model membrane is the first and essential step in studying the membrane protein in vitro. Commonly used membrane mimics include detergent micelles, detergent/lipid bicelles, and lipo somes (reviewed in the previous chapter). A newer model system is the “nanodisc,” originally designed by Dr. Sligar [1]. The nanodisc’s properties as a model membrane are discussed at length in this chapter, but in general its defining qualities are that it is a stable membrane mimic with a precisely controlled size and stoichiometry, making it a suitable system to study membrane proteins in their native environments.
Yunchen Bi
Chapter 3. Calcium Regulates T Cell Receptor Activation by Modulating Phospholipid Electrostatic Property
Abstract
Ionic protein-lipid interactions are critical for the structure and function of membrane receptors, ion channels, adhesion molecules, Ras superfamily small GTPases and other proteins.
Yunchen Bi
Chapter 4. Study on the Structure of Dengue Virus NS2B–NS3p in Complex with Aprotinin
Abstract
Dengue virus, a member of Flaviviridae, is one of the most prevalent Mosquito-borne viruses in tropical and subtropical regions of the world. It causes a range of clinical diseases, such as dengue fever, dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) [1]. Lack of approved vaccine or effective antiviral therapy for these diseases puts millions of lives at risk. Like other flaviviruses, the genome of dengue virus contains a positive single-stranded 11-kilobases RNA, which encodes three structural proteins (capsid protein C, membrane protein M, and envelope protein E) and seven non-structural proteins (NS1, NS2A, NS2B, NS3, NS4A, NS4B, and NS5) [2]. The N-terminus of NS3 (NS3p) functions as a serine protease, whose catalytic activity requires NS2B. A combination of NS2B–NS3p and the host proteases, cleaves the viral polyprotein into individual mature proteins. Therefore it is essential for viral replication [3]. Aprotinin, a classic inhibitor for trypsin and related proteolytic enzymes, was reported to inhibit the activity of NS2B–NS3p protease at submicromolar concentration [4]. In this chapter, the backbone 1H, 15N, 13C resonance assignments of the N terminal fragment of NS2B (4.8 kDa) and NS3p (18.5 kDa) in complex with aprotinin (6.5 kDa) is reported, which provides a requisite step for determining the solution structure of the complex. It is also important for screening and developing new antiviral drugs by structure-based designing strategies.
Yunchen Bi
Backmatter
Metadaten
Titel
Study of the Calcium Regulation Mechanism of TCR Activation Using Nanodisc and NMR Technologies
verfasst von
Yunchen Bi
Copyright-Jahr
2018
Verlag
Springer Berlin Heidelberg
Electronic ISBN
978-3-662-54618-5
Print ISBN
978-3-662-54616-1
DOI
https://doi.org/10.1007/978-3-662-54618-5

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