Related Experiment Video
Updated: Aug 9, 2026

Using an α-Bungarotoxin Binding Site Tag to Study GABA A Receptor Membrane Localization and Trafficking
Published on: March 28, 2014
Enhanced G-protein activation by a mixture of Abeta(25-35), Abeta(1-40/42) and zinc
Zs Molnár1, P Kovács, I Laczkó
1Department of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, PO Box 521, H-6701 Szeged, Hungary.
Abstract:
Beta-amyloid peptides (Abetas) bind to several G-protein coupled receptor proteins and stimulate GTPase activity in neurons. In this study we determined the effects of Abeta(1-42), Abeta(1-40), Abeta(25-35) and their mixtures on [(35)S]GTP binding in rat brain cortical membranes in the absence and presence of zinc. We found that the Abetas alone induced a concentration-dependent activation of G-proteins (IC50 approximately 10(-6) m), while aggregated Abeta fibrils only affected GTP binding at concentrations above 10(-5) m. Mixing Abeta(25-35) with Abeta(1-42) or Abeta(1-40) induced a several-fold increase in GTP-binding. This potentiation followed a bell shaped curve with a maximum at 50 : 50 ratios. No potentiating effect could be seen by mixing Abeta(1-40) and Abeta(1-42) or highly aggregated Abetas. Zinc had no effect on Abeta(1-40/42) but strongly potentiated the Abeta(25-35) or the mixed peptides-induced GTP-binding. Changes in secondary structure accompanied the mixed peptides or the peptide/zinc complexes induced potentiation, revealing that structural alterations are behind the increased biological action. These concentration dependent potentiating effects of zinc and the peptide mixtures could be physiologically important at brain regions where peptide fragments and/or zinc are present at elevated concentrations.
More Related Videos
07:41A Kinetic Fluorescence-based Ca2+ Mobilization Assay to Identify G Protein-coupled Receptor Agonists, Antagonists, and Allosteric Modulators
Published on: February 20, 2018
07:16Methods for the Discovery of Novel Compounds Modulating a Gamma-Aminobutyric Acid Receptor Type A Neurotransmission
Published on: August 16, 2018
Related Concept Videos
G-protein Coupled Receptors
G Protein-coupled Receptors
GPCRs are also called heptahelical, 7TM, or serpentine receptors, and consist of seven (H1-H7) transmembrane alpha-helices that span the bilayer to form a cylindrical core. The transmembrane helices are connected by three extracellular loops and three...
Activation and Inactivation of G Proteins
GPCR Desensitization
GPCRs Regulate Adenylyl Cylase Activity
Two...
Transducer Mechanism: G Protein–Coupled Receptors
GPCRs are also called heptahelical, 7TM, or...