Related Experiment Video
Updated: May 24, 2026
07:41
A Kinetic Fluorescence-based Ca2+ Mobilization Assay to Identify G Protein-coupled Receptor Agonists, Antagonists, and Allosteric Modulators
Published on: February 20, 2018
NCAM180 regulates Ric8A membrane localization and potentiates β-adrenergic response
Marie-Claude Amoureux1, Stéphane Nicolas, Geneviève Rougon
1Institut de Biologie du Développement de Marseille-Luminy, Aix-Marseille Université CNRS 6216, Marseille, France. Marie-Claude.Amoureux@ibdml.univmed.fr
Plos One
|March 3, 2012
Summary
The Neural Cell Adhesion Molecule (NCAM) isoform 180 interacts with guanine nucleotide exchange factor Ric8A, forming a complex that regulates G protein signaling. This crosstalk between NCAM and G protein-coupled receptors (GPCRs) influences cellular responses in the nervous system.
Area of Science:
- Neuroscience
- Cell Biology
- Molecular Biology
Background:
- Receptor cooperation integrates intracellular signaling for physiological responses.
- Neural Cell Adhesion Molecule (NCAM) has three isoforms (120, 140, 180 kDa) with adhesive and signaling roles, but their functions are not fully understood.
- Guanine nucleotide exchange factor Ric8A is crucial for G protein activity at GPCRs, neurotransmitter release, and cell division.
Purpose of the Study:
- To identify novel interactors of NCAM isoforms.
- To elucidate the functional relationship between NCAM and Ric8A in G protein signaling.
- To investigate the role of NCAM isoforms in modulating GPCR responses.
Main Methods:
- Yeast two-hybrid system and immunoprecipitation to identify protein interactions.
- Confocal microscopy for colocalization studies.
- In vitro recombinant systems and in vivo studies using NCAM knock-out mouse brains.
- siRNA-mediated inhibition and overexpression of Ric8A.
- Measurement of cAMP production following β-adrenergic receptor stimulation.
Main Results:
- Human NCAM180 intracellular domain interacts with human GEF Ric8A.
- NCAM, Ric8A, and G(αs) form a tripartite complex.
- NCAM180 recruits Ric8A to the membrane and dose-dependently regulates Ric8A redistribution in detergent-resistant membrane microdomains (DRM).
- Ric8A modulates cAMP production; NCAM180 potentiates G(αs)-coupled β-adrenergic receptor response in a Ric8A-dependent manner, unlike NCAM120 or NCAM140.
- NCAM is essential for isoproterenol-induced cAMP production in mouse hippocampal neurons, dependent on Ric8A.
Conclusions:
- NCAM180 is a novel interactor of Ric8A, forming a functional complex that influences G(αs) signaling.
- NCAM180 specifically modulates GPCR activity via Ric8A, highlighting a crosstalk between IgCAMs and GPCRs in the nervous system.
- This interaction provides new insights into integrated signaling pathways regulating neuronal function.
Related Concept Videos
01:26Adrenergic Receptors: β Subtype
β-adrenoceptors have varied sensitivities towards adrenaline, noradrenaline, and isoprenaline. The order of agonist potency is as follows:
Isoprenaline > Adrenaline > Noradrenaline
Neurotransmitter binding to these receptors causes activation of adenylyl cyclase resulting in increased concentrations of cAMP and modulation of calcium ion channels within the cell. They are further classified into β1, β2, and β3 subtypes.
β1-adrenoceptors: β1-adrenoceptors have equal affinities for...
Isoprenaline > Adrenaline > Noradrenaline
Neurotransmitter binding to these receptors causes activation of adenylyl cyclase resulting in increased concentrations of cAMP and modulation of calcium ion channels within the cell. They are further classified into β1, β2, and β3 subtypes.
β1-adrenoceptors: β1-adrenoceptors have equal affinities for...
01:09GPCRs Regulate Adenylyl Cylase Activity
Some GPCRs transmit signals through adenylyl cyclase (AC), a transmembrane enzyme. AC helps synthesize second messenger cyclic adenosine monophosphate (cAMP). AC catalyzes cyclization reaction and converts ATP to cAMP by releasing a pyrophosphate. The pyrophosphate is further hydrolyzed to phosphate by the enzyme pyrophosphatase, which drives cAMP synthesis to completion. However, cAMP is rapidly degraded to 5′ AMP by the enzymes phosphodiesterase (PDE), preventing overstimulation of cells.
Two...
Two...
01:27Adrenergic Receptors (Adrenoceptors): Classification
Adrenergic receptors, or adrenoceptors, respond to the autonomic neurotransmitter noradrenaline and other endogenous catecholamine agonists. They are classified into two main families, α and β, based on their pharmacological response and are further subdivided depending on their location, elicited response, and affinity to specific agonists or antagonists.
α-Adrenoceptors
α-Adrenoceptors are classified into two main subtypes: α1 and α2. The α1 adrenoceptors, which are found on postsynaptic...
α-Adrenoceptors
α-Adrenoceptors are classified into two main subtypes: α1 and α2. The α1 adrenoceptors, which are found on postsynaptic...
01:16Calmodulin-dependent Signaling
Calmodulin (CaM) is a calcium-binding protein in eukaryotes that controls various calcium-regulated cellular processes. It has four calcium-binding sites that bind calcium to form the calcium-calmodulin ( Ca2+-CaM) complex. GPCR stimulation increases the calcium levels in the cells that bind to CaM and induces a conformational change.
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
01:21G-Protein Gated Ion Channels
GPCRs are primarily responsible for our sense of smell, taste, and vision. The binding of a sensory stimulus activates GPCR to stimulate effector proteins, many of which are ion channels in the sensory organs. GPCRs modulate the opening and closing of the target ion channels either directly by binding them, or by releasing second messengers that activate these channels. As ions move across the membrane, the membrane potential is altered, which induces an appropriate response.
Sensory organs,...
Sensory organs,...
01:31Adrenergic Receptors: ɑ Subtype
Adrenoceptors are classified into α and ꞵ classes based on their potencies to catecholamine agonists. α-adrenoceptors show the following order of catecholamine potency:
Adrenaline ≥ Noradrenaline >> Isoprenaline
α-adrenoceptors are further divided into α1 and α2-adrenoceptors.
α1-Adrenoceptors: These receptors are located postsynaptically on the effector organs and cause constriction of smooth muscle mediated by activation of phospholipase C—inositol-1,4,5-trisphosphate...
Adrenaline ≥ Noradrenaline >> Isoprenaline
α-adrenoceptors are further divided into α1 and α2-adrenoceptors.
α1-Adrenoceptors: These receptors are located postsynaptically on the effector organs and cause constriction of smooth muscle mediated by activation of phospholipase C—inositol-1,4,5-trisphosphate...