Related Experiment Video
Updated: May 18, 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
PLCβ isoforms differ in their subcellular location and their CT-domain dependent interaction with Gαq
Merel J W Adjobo-Hermans1, Kevin C Crosby, Mateusz Putyrski
1Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands. m.adjobo-hermans@ncmls.ru.nl
Cellular Signalling
|September 26, 2012
Summary
Phospholipase C (PLC) β isoforms show distinct subcellular localizations. The C-terminal domain inhibits Gq-mediated calcium increases, with PLCβ3 and Gαq interacting transiently at the plasma membrane.
Area of Science:
- Biochemistry
- Cell Biology
- Molecular Physiology
Background:
- Phospholipase C (PLC) β isoforms are crucial in various physiological processes and pathologies.
- Limited mechanistic understanding exists regarding the specific localization and activation of individual PLCβ isoforms.
- In-depth knowledge of PLCβ isoform regulation is essential for understanding their diverse roles.
Purpose of the Study:
- To investigate the subcellular localization of full-length PLCβ isozymes and their C-terminal (CT) domains.
- To elucidate the inhibitory role of the CT domain on Gq-mediated calcium signaling.
- To analyze the kinetics of Gαq-CTβx interactions and their impact on PLCβ localization.
Main Methods:
- Subcellular localization studies of PLCβ isozymes and their CT domains.
- Assessment of Gq-mediated intracellular calcium changes.
- Ratiometric fluorescence resonance energy transfer (FRET) imaging to study Gαq-CTβx interactions.
- On-demand activation of Gαq using novel tools.
Main Results:
- PLCβ1 and PLCβ4 were found to be enriched at the plasma membrane, unlike PLCβ2 and PLCβ3.
- The CT domain acts as an inhibitor of Gq-mediated calcium increases, with potency varying by isoform.
- Interaction between constitutively active Gαq and PLCβ3 prolonged PLCβ3's plasma membrane residence time.
- PLCβ3 and Gαq exhibit a transient, 'kiss-and-run' interaction at the plasma membrane.
Conclusions:
- Distinct subcellular localization patterns exist among PLCβ isoforms.
- The PLCβ CT domain plays a regulatory role in Gq signaling pathways.
- PLCβ3 and Gαq engage in dynamic, transient interactions at the plasma membrane, potentially regulated by PLCβ's GTPase-activating activity.
Related Concept Videos
01:22Activation and Inactivation of G Proteins
Heterotrimeric G proteins are guanine nucleotide-binding proteins. As the name suggests, heterotrimeric G proteins are composed of three subunits: alpha, beta, and gamma. They remain GDP-bound or GTP-bound inside the cells and switch between inactive/active states. The Gα subunit possesses the nucleotide-binding pocket that binds guanine nucleotides and switches between GDP or GTP-bound states. In contrast, the Gꞵ and Gγ subunits are always bound together with high affinity and are together...
01:21G-protein Coupled Receptors
G-protein coupled receptors are ligand binding receptors that indirectly affect changes in the cell. The actual receptor is a single polypeptide that transverses the cell membrane seven times creating intracellular and extracellular loops. The extracellular loops create a ligand specific pocket which binds to neurotransmitters or hormones. The intracellular loops holds onto the G-protein.
01:21G-protein Coupled Receptors
G-protein coupled receptors are ligand binding receptors that indirectly affect changes in the cell. The actual receptor is a single polypeptide that transverses the cell membrane seven times creating intracellular and extracellular loops. The extracellular loops create a ligand specific pocket which binds to neurotransmitters or hormones. The intracellular loops holds onto the G-protein.
01:30Transducer Mechanism: G Protein–Coupled Receptors
G Protein–Coupled Receptors (GPCRs) are membrane-bound receptors that transiently associate with heterotrimeric G proteins and induce an appropriate response to various stimuli. GPCRs regulate critical physiological pathways and are excellent drug targets for treating diseases such as diabetes, cancer, obesity, depression, or Alzheimer's. Nearly 35% of approved drugs implement their therapeutic effects by selectively interacting with specific GPCRs.
GPCRs are also called heptahelical, 7TM, or...
GPCRs are also called heptahelical, 7TM, or...
01:15G Protein-coupled Receptors
G Protein-Coupled Receptors or GPCRs are membrane-bound receptors that transiently associate with heterotrimeric G proteins and induce an appropriate response to sensory stimuli such as light, odors, hormones, cytokines, or neurotransmitters.
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...
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...
01:15G Protein-coupled Receptors
G Protein-Coupled Receptors or GPCRs are membrane-bound receptors that transiently associate with heterotrimeric G proteins and induce an appropriate response to sensory stimuli such as light, odors, hormones, cytokines, or neurotransmitters.
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...
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...