Characterization and regulation of the expression of scyllatoxin (Leiurotoxin I) receptors in the human neuroblastoma cell line NB-OK 1. |
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| Authors: | D Gossen J C Gesquière M Tastenoy P De Neef M Waelbroeck J Christophe |
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| Institution: | Department of Biochemistry and Nutrition, Medical School, Université Libre de Bruxelles, Belgium. |
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| Abstract: | 125I-Tyr2]scyllatoxin allowed to label a single class of high-affinity receptors in membranes from the human neuroblastoma cell line NB-OK 1. The Kd of these receptors was 60 pM for scyllatoxin (Leiurotoxin I) and 20 pM for apamin and the Bmax was low (3.8 fmol/mg membrane protein). K+ increased toxin binding at low concentrations but exerted opposite effects at high concentrations. Ca2+, guanidinium and Na+ exerted only inhibitory effects on binding. Scyllatoxin binding sites were overexpressed 2.5-fold after a 24-h cell pretreatment with 2 mM butyrate. This effect was suppressed by cycloheximide. |
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