Related Experiment Video
Updated: Nov 8, 2025
09:03
Parallel Interrogation of β-Arrestin2 Recruitment for Ligand Screening on a GPCR-Wide Scale using PRESTO-Tango Assay
Published on: March 10, 2020
13.1K
β-arrestin-dependent PI(4,5)P2 synthesis boosts GPCR endocytosis
Seung-Ryoung Jung1,2,3, Yifei Jiang2, Jong Bae Seo4,5
1Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195; jsr007@uw.edu.
Summary
Beta-arrestins enhance the synthesis of phosphatidylinositol-(4,5)-bisphosphate (PI(4,5)P2), a key lipid, to promote G protein-coupled receptor (GPCR) endocytosis. This finding reveals a novel role for beta-arrestins in regulating cellular signaling and membrane trafficking.
Area of Science:
- Cellular Biology
- Molecular Pharmacology
- Biochemistry
Background:
- Beta-arrestins are crucial regulators of G protein-coupled receptor (GPCR) signaling, desensitization, and endocytosis.
- Plasma membrane phosphoinositides, particularly phosphatidylinositol-(4,5)-bisphosphate (PI(4,5)P2), modulate beta-arrestin functions.
- The precise mechanisms by which beta-arrestins influence PI(4,5)P2 levels and receptor trafficking remain incompletely understood.
Purpose of the Study:
- To investigate the role of beta-arrestin in the synthesis of PI(4,5)P2.
- To elucidate how beta-arrestin regulates GPCR endocytosis, focusing on the protease-activated receptor 2 (PAR2) as a model.
- To determine the impact of beta-arrestin on phosphoinositide metabolism and the formation of endocytic machinery.
Main Methods:
- Utilized live-cell imaging with lipid-specific fluorescent probes and genetic tools to monitor and control phosphoinositides.
- Employed the Gq-coupled PAR2 system, activated by a specific agonist, to study receptor desensitization and endocytosis.
- Manipulated PI(4,5)P2 levels using recruitable phosphatases and assessed the effects of beta-arrestin knockdown on PIP5-kinase activity.
Main Results:
- PAR2 activation led to PI(4,5)P2 depletion, followed by recovery during desensitization, preceding endocytosis.
- Depletion of PI(4)P or PI(4,5)P2 significantly reduced endocytosis, highlighting the requirement for these lipids.
- Beta-arrestin knockdown revealed that beta-arrestin normally doubles PIP5-kinase activity post-desensitization, boosting PI(4,5)P2 synthesis for clathrin-coated pit formation.
- Desensitized PAR2 receptors exhibited prolonged immobilization at clathrin-coated pits, with beta-arrestin and PIP5K accumulating at these sites.
Conclusions:
- Beta-arrestins actively promote PI(4,5)P2 synthesis at the plasma membrane through enhanced PIP5-kinase activity.
- This localized PI(4,5)P2 generation is essential for recruiting the endocytic machinery and driving GPCR internalization.
- Beta-arrestins play a dual role in GPCR regulation: mediating desensitization and actively promoting endocytosis via phosphoinositide synthesis.
More Related Videos
Related Concept Videos
01:12GPCR Desensitization
7.1K
G protein-coupled receptor (GPCR) signaling plays a crucial role in cell functioning. GPCR desensitization is an equally essential process. It allows cells to respond to changing environments and regain sensitivity to new stimuli while preventing unnecessary stimulation when no longer needed. Prolonged exposure to stimuli leads to GPCR desensitization. It involves blocking the receptors from binding and activating additional G proteins. This inhibits activation of downstream effectors, thereby...
7.1K
01:11IP3/DAG Signaling Pathway
13.2K
Membrane lipids such as phosphatidylinositol (PI) are precursors for several membrane-bound and soluble second messengers. Specific kinases phosphorylate PI and produce phosphorylated inositol phospholipids. One such inositol phospholipids are the phosphatidylinositol-4,5 bisphosphate [PI(4,5)P2], present in the inner half of the lipid bilayer. Upon ligand binding, GPCR stimulates Gq proteins to turn on phospholipase Cꞵ. Activated phospholipase Cꞵ cleaves PI(4,5)P2 and...
13.2K
01:09GPCRs Regulate Adenylyl Cylase Activity
6.3K
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...
6.3K
01:21G-protein Coupled Receptors
127.7K
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.
127.7K
01:33Coat Assembly and GTPases
3.9K
Vesicles incorporate different coat protein subunits in different cell locations, which changes the properties of the coat, such as the shape and geometry of the transport vesicles. Thus, vesicle coat proteins also play a significant role in cargo selection.
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...
3.9K
01:15G Protein-coupled Receptors
14.8K
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...
14.8K