Related Experiment Video

Updated: Aug 14, 2026

Parallel Interrogation of β-Arrestin2 Recruitment for Ligand Screening on a GPCR-Wide Scale using PRESTO-Tango Assay
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

Arrestin-mediated ERK activation by gonadotropin-releasing hormone receptors: receptor-specific activation mechanisms

Christopher J Caunt1, Ann R Finch, Kathleen R Sedgley

  • 1Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, Whitson Street, Bristol BS1 3NY, United Kingdom.

The Journal of Biological Chemistry
|November 30, 2005
PubMed

Insights

This study reveals arrestin-mediated signaling for Xenopus GnRH receptors (GnRHRs), distinct from human GnRHRs which utilize other scaffolds for ERK pathway regulation. This highlights differences in GnRHR signaling mechanisms.

Area of Science:

  • Cellular signaling
  • Molecular biology
  • Receptor pharmacology

Background:

  • Seven-transmembrane receptors (e.g., GnRH receptors) signal via G proteins and can interact with arrestins.
  • Arrestins mediate receptor desensitization and can scaffold signaling proteins like ERK.
  • Mammalian GnRH receptors (GnRHRs) lack C-tails, potentially affecting arrestin interaction compared to non-mammalian counterparts.

Purpose of the Study:

  • To compare ERK signaling pathways activated by human GnRHRs (hGnRHRs) and Xenopus GnRHRs (XGnRHRs).
  • To investigate the role of arrestins in GnRHR-mediated ERK phosphorylation and translocation.
  • To elucidate differences in signaling mechanisms based on receptor type and expression levels.

Main Methods:

  • Utilized HeLa cells expressing hGnRHRs and XGnRHRs.
  • Monitored receptor internalization, arrestin translocation (using arrestin-GFP), and ERK phosphorylation/nuclear translocation (using ERK2-GFP).
  • Employed pharmacological inhibitors (PKC inhibitor) and dominant-negative arrestin constructs.

Main Results:

  • XGnRHRs showed rapid, arrestin-dependent internalization and co-localization with arrestin-GFP, unlike hGnRHRs.
  • Both receptors mediated transient ERK phosphorylation and nuclear translocation, influenced by PKC.
  • Arrestin inhibition blocked XGnRHR-mediated ERK phosphorylation but not hGnRHR-mediated signaling.
  • hGnRHRs were more efficient at activating phospholipase C and ERK but less efficient at ERK translocation than XGnRHRs.
  • Receptor number influenced ERK translocation, with XGnRHRs showing translocation at low numbers, unlike hGnRHRs.

Conclusions:

  • Xenopus GnRHRs demonstrate direct, likely G protein-independent, arrestin-mediated signaling.
  • Human GnRHRs appear to rely on non-arrestin scaffolds for regulating ERK compartmentalization.
  • Differences in GnRHR structure (C-tails) correlate with distinct arrestin engagement and downstream signaling outcomes.

More Related Videos

Monitoring GPCR-β-arrestin1/2 Interactions in Real Time Living Systems to Accelerate Drug Discovery08:21

Monitoring GPCR-β-arrestin1/2 Interactions in Real Time Living Systems to Accelerate Drug Discovery

Published on: June 28, 2019

Detection of Ligand-activated G Protein-coupled Receptor Internalization by Confocal Microscopy10:24

Detection of Ligand-activated G Protein-coupled Receptor Internalization by Confocal Microscopy

Published on: April 9, 2017

Related Concept Videos

Amplifying Signals via Enzymatic Cascade01:22

Amplifying Signals via Enzymatic Cascade

When a ligand binds to a cell-surface receptor, the receptor's intracellular domain changes shape, which may either activate its enzyme function or allow its binding to other molecules. The initial signal is amplified by most signal transduction pathways. This means that a single ligand molecule can activate multiple molecules of a downstream target. Proteins that relay a signal are most commonly phosphorylated at one or more sites, activating or inactivating the protein. Kinases catalyze the...
GPCRs Regulate Adenylyl Cylase Activity01:09

GPCRs 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...
Activation and Inactivation of G Proteins01:22

Activation 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...
Assembly of Signaling Complexes01:30

Assembly of Signaling Complexes

Multiprotein signaling complexes are formed in a dynamic process involving protein-protein interactions at the cytoplasmic domain of transmembrane receptors or enzymatic and non-enzymatic proteins associated with the receptor. These complexes ensure the activation and propagation of intracellular signals that regulate cell functions.
Interaction domains in cell signaling
Interaction domains recognize exposed features of their binding partners containing post-translationally modified sequences,...
Secondary Messengers in Hormone Action01:26

Secondary Messengers in Hormone Action

Water-soluble hormones cannot cross the plasma membrane, so they rely on protein receptors that span the membrane to trigger intracellular signaling pathways. These pathways then activate second messengers inside the cell, including cAMP or calcium ions.
Many hormones bind to transmembrane G protein-coupled receptors that connect to regulatory G proteins. These G proteins can then activate enzymes such as adenylyl cyclase or phospholipase C. Adenylyl cyclase converts ATP to cAMP, activating...
Receptor Tyrosine Kinases01:26

Receptor Tyrosine Kinases

Receptor tyrosine kinases or RTKs are membrane-bound receptors that phosphorylate specific tyrosine on protein substrates. RTKs regulate cellular growth, differentiation, survival, and migration. They contain an extracellular ligand binding domain, a transmembrane domain, and a cytosolic tail with intrinsic kinase activity. Several extracellular signaling molecules activate RTKs in one or more ways and relay the signal downstream. Ligands such as platelet-derived growth factor (PDGF) or...