Receptor anchoring

Stallmeyer, B., Schwarz, G., Schulze, J., Nerlich, A., Reiss, J., Kirsch, j., and Mendel, R. R. The neurotransmitter receptor-anchoring protein gephyrin reconstitutes molybdenum cofactor biosynthesis in bacteria, plants, and mammalian cells, Proc Natl Acad Sci USA 1999, 96, 1333-1338. 

Figure 11.24 A silicon wafer array, with micromachined pyramidal wells (detail shown right) for holding receptor derivatised beads. Fluid containing the experimental solution is added to the top of the array and flows through the bead matrix, and out of the bottom of the pyramidal wells holding the beads. Analyte binding by the differential receptors anchored to the beads gives a recognition pattern unique to each analyte mixture (reproduced with permission from [34] 2001 American Chemical Society).

Receptors anchored to the plasma membrane by lipids Glycosylphosphatidylinositol (GPI)-anchored proteins and glycolipids... 

Commentary on Energy landscapes of biomolecular adhesion and receptor anchoring at interfaces explored with dynamics force spectroscopy, E. Evans, Faraday Discuss., 1998, 111, 1. 

Wyszynski M, Kharazia V, Shanghvi R, Rao A, Beggs AH, et al. 1998. Differential regional expression and ultrastructural localization of alpha-actinin-2, a putative NMDA receptor-anchoring protein, in rat brain. J. Neurosci. 18 1383-92... 

Mechanism of action of cholera toxin. The steps consist of cholera toxin (CT) binding to GMi receptors anchored by its ceramide moiety internalization of CT in endosomes the release of A1-subunit of CT from the trans-Golgi network and endoplasmic reticulum (ER) ADP ribosylation of the a-subunit of stimulatory G-protein by At activation of adenylyl cyclase and production of cAMP activation of protein kinase A phosphorylation of the regulatory (R) subunit of CFTR and finally opening of the chloride channel. Vibrio cholerae also produces a zona occludens toxin (ZOT) which increases the ionic permeability of the zona occludens. 

Wyszynski M, Kim E, Yang F-C, Sheng M (1998b) Biochemical and immunocytochemical characterization of GRIP, a putative AMPA receptor anchoring protein, in rat brain. Neuropharmacology 37 1335-1344. 

Figure S.21 The hemaggiutinin moiecuie is formed from three subunits. Each of these subunits Is anchored In the membrane of the influenza vims. The globular heads contain the receptor sites that bind to sialic acid residues on the surface of eukaryotic cells. A major part of the subunit interface is formed by the three long intertwining helices, one from each subunit. (Adapted from I. Wilson et al.. Nature 289 366-373, 1981.)...

Figure 13.2 Activated G protein receptors, here represented as seven red transmembrane helices, catalyze the exchange of GTP for GDP on the Gapy trimer. The then separated Ga-GTP and Gpy molecules activate various effector molecules. The receptor is embedded in the membrane, and Ga, Gpy and G py are attached to the membrane by lipid anchors, and they all therefore move in two dimensions. (Adapted from D. Clapham, Nature 379 297-299, 1996.)...

A variety of cellular and viral proteins contain fatty acids covalently bound via ester linkages to the side chains of cysteine and sometimes to serine or threonine residues within a polypeptide chain (Figure 9.18). This type of fatty acyl chain linkage has a broader fatty acid specificity than A myristoylation. Myristate, palmitate, stearate, and oleate can all be esterified in this way, with the Cjg and Cjg chain lengths being most commonly found. Proteins anchored to membranes via fatty acyl thioesters include G-protein-coupled receptors, the surface glycoproteins of several viruses, and the transferrin receptor protein. 

FIGURE 15.21 Hormone (H) binding to its receptor (R) creates a hormone receptor complex (H R) that catalyzes GDP-GTP exchange on the o -subunit of the heterotrimer G protein (G ), replacing GDP with GTP. The G -subunit with GTP bound dissociates from the /37-subunits and binds to adenylyl cyclase (AC). AC becomes active upon association with G GTP and catalyzes the formation of cAMP from ATP. With time, the intrinsic GTPase activity of the G -subunit hydrolyzes the bound GTP, forming GDP this leads to dissociation of G GDP from AC, reassociation of G with the /Sy subunits, and cessation of AC activity. AC and the hormone receptor H are integral plasma membrane proteins G and G are membrane-anchored proteins. 

Several nonconventional cadherins that contain cadherin repeats have been described but they have specific features not found in the classical cadherins [1]. The cadherin Flamingo, originally detected in Drosophila, contains seven transmembrane segments and in this respect resembles G protein-coupled receptors. The extracellular domain of Flamingo and its mammalian homologs is composed of cadherin repeats as well as EGF-like and laminin motifs. The seven transmembrane span cadherins have a role in homotypic cell interactions and in the establishment of cell polarity. The FAT-related cadherins are characterized by a large number of cadherin repeats (34 in FAT and 27 in dachsous). Their cytoplasmic domains can bind to catenins. T- (=truncated-)cadherin differs from other cadherins in that it has no transmembrane domain but is attached to the cell membrane via a glycosylpho-sphatidylinositol anchor. 

Smad anchor for receptor activation) An intracellular protein Sara which accumulates at early endosomes and plays a key role in TGF- 3 signal transduction through the recruitment of receptor activated R-Smads for phosphorylation by the type ITGF-B receptor. 

Many GPCRs contain one or more conserved cysteine residues within their C-terminal tails, which are modified by covalent attachment of palmitoyl or isoprenyl residues. The palmitoyl moiety is anchored in the lipid bilayer forming a fourth intracellular loop. There is evidence that palmitoylation of a GPCR is a dynamic process and may affect receptor desensitization. 

As early as 1848, it had been suggested that sensory receptors transduce only one sensation, independent of the manner of stimulation. Behavioral experiments tend to support this theory. In 1919, Renqvist proposed that the initial reaction of taste stimulation takes place on the surface of the taste-cell membrane. The taste surfaces were regarded as colloidal dispersions in which the protoplasmic, sensory particles and their components were suspended in the liquor or solution to be tested. The taste sensation would then be due to adsorption of the substances in the solution, and equal degrees of sensation would correspond to adsorption of equal amounts. Therefore, the rate of adsorption of taste stimulants would be proportional to the total substances adsorbed. The phenomenon of taste differences between isomers was partly explained by the assumption that the mechanism of taste involves a three-dimensional arrangement for example, a layer of fatty acid floating on water would have its carboxylic groups anchored in the water whereas the long, hydrocarbon ends would project upwards. 

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