Structural Studies Of Receptor Tyrosine Kinases 451 Ligand Binding Domains

Several structures of ligand-binding domains of RTKs have been reported in the last 10 years, providing a basis for understanding dimerization mechanisms and ligand-receptor specificity (Table 4.1). The structures include receptors for cytokines such as growth hormone, prolactin, and eryth-ropoietin, as well as receptors for growth factors such as insulin-like growth factor I, fibroblast growth factor, nerve growth factor, and vascular endothelial growth factor. In general, only a subset...

The 4tm Receptors

The 4TM family of receptors consists of the nicotinic acetylcholine receptor (nAChR), serotonin receptor (5HT3), glycine receptor, and y-aminobutyric acid receptors (GABAa and GABAC). The nAChRs are the primary excitatory receptors in the skeletal muscle and the peripheral nervous system of vertebrates. In the central nervous system, nAChRs are present in much smaller number than the glutamate receptors. 5HT3 receptors are also cation-selective but are located exclusively on neurons. Glycine...

The PKB Signaling Pathway

The tyrosine phosphorylated growth factor receptors recruit p85PI3-kinase, an adaptor molecule that associates with p110PI3-kinase, and together they form a lipid kinase called phosphatidylinositol-3 kinase (PI3-kinase). This protein kinase plays an important role in a number of cellular processes regulation of glycogenesis (in response to insulin), regulation of cell size, migration, survival, and proliferation. In this chapter, we will focus on its role in cellular proliferation (EGF, PDGF)...

Introduction

The term receptor is used in pharmacology to denote a class of cellular macromolecules that are concerned specifically and directly with chemical signaling between and within cells. Combination of a hormone, neurotransmitter, or intracellular messenger with its receptor(s) results in a change in cellular activity. Hence, a receptor must not only recognize the particular molecules that activate it, but also, when recognition occurs, alter cell function by causing, for example, a change in...