Receptor Family

Dmg receptors represent another type of receptor family. The central nervous system (CNS) effects of the anxiolytic, diazepam, and the psychotropic actions of the caimabiaoids and phencycUdine have resulted ia the identification of specific receptors for these molecules. This has resulted ia the search for an endogenous ligand for these receptors. Thus, ia these situations, the pharmacological action has preceded the discovery of the receptor which, ia turn, has provided clues ia several iastances to the endogenous ligand. 

The class II cytokine receptor family includes receptors for interferon a/P (lEN a/P) and y (lENy) and IL-10. lEN-y immunoreactivity has been found in neurons in the hypothalamus, cerebral cortex, mammilary nuclei, and dorsal tegmentum. Astrocytes and microglia in vitro can be stimulated to express class II histocompatibiHty complex (MHC-II) antigens by lEN-y, which may be involved in the presentation of antigen to T-ceUs by astrocytes. Thus lEN-y may be critical in CNS-immune function and dysfunction especially in regard to neuronal and gHal apoptotic processes. 

The class III cytokine receptor family includes two TNE receptors, the low affinity NGE receptor and 7-ceU surface recognition sites that appear to play a role in proliferation, apoptosis, and immunodeficiency. TNE-a (- 17, 000 protein) is produced by astrocytes and microglia and can induce fever, induce slow-wave sleep, reduce feeding, stimulate prostaglandin synthesis, stimulate corticotrophin-releasing factor and prolactin secretion, and reduce thyroid hormone secretion. TNE-a stimulates IL-1 release, is cytotoxic to oligodendrocytes, and reduces myelination this has been impHcated in multiple sclerosis and encephalomyelitis. Astrocyte TNE-a receptors mediate effects on IL-6 expression and augment astrocytic expression of MHC in response to other stimulants such as lEN-y. 

The G-proteins are heterotrimers made of three families of subunits, a, P, and y, which can interact specifically with discrete regions on G-protein-coupled receptors. This includes most receptors for neurotransmitters and polypeptide hormones (see Neuroregulators). G-protein-coupled receptors also embrace the odorant receptor family and the rhodopsin-linked visual cascade. 

In this chapter we describe some examples of structures of membrane-bound proteins known to high resolution, and outline how the elucidation of these structures has contributed to understanding the specific function of these proteins, as well as some general principles for the construction of membrane-bound proteins. In Chapter 13 we describe some examples of the domain organization of receptor families and their associated proteins involved in signal transduction through the membrane. 

Epidermal Growth Factor Receptor Family Growth Factors... 

Currently no drugs directly modulating the LDL receptor family are known. The possible use of drugs targeting the LDL receptor family or downstream signaling proteins may be derived from Table 1. 

For differentiation of G-protein-coupled receptor sub-types from subtypes permanently linked to ion channels (ligand-gated ion channels) the terms metabotropic versus ionotropic receptors, respectively, are used. Prime examples of metabotropic receptors are given by the lnGlu receptor family of G-protein-coupled glutamate receptors. 

Epidermal Growth Factor (EGF) Receptor Family Epidermal Growth Factor Receptor 2 (ErbB2) Epidural (Space)... 

ErbB Receptor Family Erectile Dysfunction ERGIC... 

Hsps serve other ftmctions during nonstressful conditions. Hsp90 acts as a molecular brake for the steroid receptor family (Bresnick et al., 1988 Bagchi et al., 1990,1991). The complex of hsp90 and the glucocorticoid receptor prevents DNA binding of the receptor until the ligand for the receptor is present (Cadepond et al.,... 

Kopp EB. Medzhitov R The Toll-receptor family and control of irmate immunity. Curr Opin Immunol 1999 11 13-18. 

Cases M, Garcia-Serna R, Hettne K, Weeber M, van der Lei J, Boyer S, Mestres J. Chemical and biological profiling of an annotated compound library directed to the nuclear receptor family. Curr Top Med Chem 2005 5 763-72. 

The ligand-receptor complex serves as the initial signal for members of the nuclear receptor family. 

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