Receptors clustering

Crestani F, Lorez M, Baer K et al (1999) Decreased GABAA-receptor clustering results in enhanced anxiety and a bias for threat cues. Nat Neurosci 2 833-839... 

Adaptor protein enriched in the post-synaptic region of neurons. Important for assembly of receptor clusters and signaling complexes. 

Sharon D., Glusman G., Pilpel Y., Khen M., et al. (1999). Primate evolution of an olfactory receptor cluster diversification by gene conversion and recent emergence of pseudogenes. Genomics 61, 24-36. 

The first study was conducted to determine whether carotenoids and cholesterol share common pathways (transporters) for their intestinal absorption (During et al., 2005). Differentiated Caco-2 cells on membranes were incubated (16 h) with a carotenoid (1 pmol/L) with or without ezetimibe (EZ Zetia, an inhibitor of cholesterol transport), and with or without antibodies against the receptors, cluster determinant 36 (CD36) and scavenger receptor class B, type I (SR-BI). Carotenoid transport in Caco-2 cells (cellular uptake + secretion) was decreased by EZ (lOmg/L) as follows P-C and a-C (50% inhibition) P-cryptoxanthin and LYC (20%) LUT ZEA (1 1) (7%). EZ reduced cholesterol transport by 31%, but not retinol transport. P-Carotene transport was also inhibited by anti-SR-BI, but not by anti-CD36. The inhibitory effects of EZ and anti-SR-BI on P-C transport... 

Figure 9.5 TNF binding to its receptor (TNF-R55), with resulting clustering of the receptor and generation of intracellular signals. Binding of TNF to its other receptor (TNF-R75) also induces receptor clustering. (See text for details)...

Tadokoro, S., Tachibana, T., Imanaka, T Nishida, W and Sobue, K. (1999) Involvement of unique leucine-zipper motif of PSD-Zip45 (Homer lc/vesl-lL) in group 1 metabotropic glutamate receptor clustering. Proc. Natl. Acad. Sci. USA 96, 13801-13806. 

Kneussel, M., Brandstatter, J. H., Laube, B., Stahl, S., Muller, U., and Betz, H. (1999) Loss of postsynaptic GABAa receptor clustering in gephyrin-deficient mice. J. Neurosci. 19, 9289-9297. 

Note finally that the preceding derivations assumed that the carriers were all uniformly reactive with no restrictions due to their spatial orientation. Although cases of receptor clustering have been documented in the literature [350], this would appear to have no advantage for the cell, since, in this case, the cluster will at best behave approximately as a single site with a larger area... 

Goldstein, B. (1989). Diffusion limited effects of receptor clustering, Comm. Theor. Biol., 1, 109-127. 

R. J. Bloch, M. Velez, J. Krikorian, and D. Axelrod, Microfilaments and actin-associated proteins at sites of membrane-substrate attachment within acetylcholine receptor clusters, Exp. Cell Res. 182, 583-596 (1989). 

Caveolae, Folate Receptor, Receptor Clustering, and Potocytosis... 

JeHe, A., Bock, J., MueUer, C., Kun, J. and Gulbins E. 2001, The CD95 death domain is required for acid sphingomyehnase mediated receptor clustering. In prep. 

Although both LDL and HDL are primarily cholesterol particles, most of the cholesterol measured in the blood is assodated with LDL. The normal role of LDL is to deliver cholesterol to tissues for biosynthesis. When a cell is repairing membrane or dividing, the cholesterol is required for membrane synthesis. Bile acids and salts are made from cholesterol in the liver, and many other tissues require some cholesterol for steroid synthesis. As shown in Figure 1-15-6, about 80% of LDL are picked up by hepatocytes, the remainder by peripheral tissues. ApoB-100 is the only apoprotein on LDL, and endocytosis of LDL is mediated by apoB-100 receptors (LDL receptors) clustered in areas of cell membranes lined with the protdn clathrin. 

Siess, D., Kozak, S. and Kabat, D. (1996) Exceptional fusogenicity of Chinese hamster ovary cells with murine retroviruses suggests roles for cellular factor(s) and receptor clusters in the membrane fusion process. J VirollO, 3432-3439. 

Apoptosis is one of a number of phenotypic responses that may occur as a result of a signal transduction pathways occurring in the cell. Clustering of cellular receptors is a commonly observed first step in the mechanism of signal transduction pathways to result in apoptosis. Receptor-clustered cytoplasmic domains trigger... 

Receptor clustering also accounts for receptor internalization. The basis of this phenomenon is endocytosis via coated pits. These pits are apparent in electron micrographs as membrane invaginations coated on the inner (cytoplasmic) side with a web of the protein clathrine. It has been suggested that certain receptor proteins have structural domains that allow them to react with coated pits. Receptor clusters in coated pits are rapidly endocytosed, resulting in the formation of vesicles (endosomes) that are then... 

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