Related Experiment Video

Updated: Aug 16, 2026

Brain Slice Biotinylation: An Ex Vivo Approach to Measure Region-specific Plasma Membrane Protein Trafficking in Adult Neurons
06:18

Brain Slice Biotinylation: An Ex Vivo Approach to Measure Region-specific Plasma Membrane Protein Trafficking in Adult Neurons

Published on: April 3, 2014

Agonist-mediated endocytosis of rat somatostatin receptor subtype 3 involves beta-arrestin and clathrin coated

O J Kreuzer1, B Krisch, O Déry

  • 1Deutsches Institut für Ernährungsforschung, Abteilung Molekulare Genetik und Universität Potsdam, Arthur-Schuenert-Allee 114-116, D-14558 Potsdam-Rehbrücke, Germany.

Journal of Neuroendocrinology
|February 24, 2001
PubMed

Insights

Agonist-induced endocytosis of somatostatin receptors (sst3) involves beta-arrestin and adaptor protein complex 2, proceeding via clathrin-coated vesicles to the recycling compartment for cellular responsiveness.

Area of Science:

  • Cell Biology
  • Molecular Endocrinology
  • Receptor Trafficking

Background:

  • Somatostatin receptors (ssts) mediate cellular responses to peptide agonists.
  • Receptor endocytosis influences cellular signaling and diagnostic imaging techniques like somatostatin receptor scintigraphy.
  • Understanding sst3 internalization mechanisms is crucial for interpreting imaging results and therapeutic strategies.

Purpose of the Study:

  • To investigate the molecular mechanisms of agonist-induced endocytosis of the type 3 somatostatin receptor (sst3).
  • To determine the role of beta-arrestin and adaptor protein complexes in sst3 internalization and trafficking.
  • To elucidate the pathway of sst3 internalization and recycling in neuroendocrine cells.

Main Methods:

  • Utilized epitope-tagged sst3 (sst3HSV) in transfected rat neuroendocrine insulinoma cells.
  • Employing co-expression of enhanced green fluorescence protein (EGFP)/beta-arrestin1 fusion proteins and dominant-negative arrestin mutants.
  • Applied confocal microscopy, electron microscopy, and immunofluorescence to track receptor localization and protein interactions.

Main Results:

  • Somatostatin stimulation induced co-localization of sst3HSV with EGFP/beta-arrestin1 in endocytic vesicles.
  • Blocking beta-arrestin function inhibited sst3HSV internalization.
  • Observed transient translocation of alpha-adaptin to the plasma membrane, with alpha-adaptin and clathrin co-localizing with sst3.
  • Electron microscopy revealed sst3 in clathrin-coated pits, endosomes, and multivesicular bodies, indicating involvement in recycling pathways.
  • sst3HSV co-localized with Rab11 in a perinuclear compartment, consistent with the recycling endosome.

Conclusions:

  • Agonist-induced endocytosis of sst3 is dependent on beta-arrestin interaction.
  • The internalization process involves adaptor protein complex 2 and clathrin-coated vesicles.
  • Sst3 is directed to the recycling compartment, influencing receptor availability and cellular responsiveness.

More Related Videos

Using an α-Bungarotoxin Binding Site Tag to Study GABA A Receptor Membrane Localization and Trafficking11:57

Using an α-Bungarotoxin Binding Site Tag to Study GABA A Receptor Membrane Localization and Trafficking

Published on: March 28, 2014

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

Receptor-mediated Endocytosis01:38

Receptor-mediated Endocytosis

Overview
Receptor-mediated Endocytosis01:20

Receptor-mediated Endocytosis

Receptor-mediated endocytosis is when bulk amounts of specific molecules are imported into a cell after binding to cell surface receptors. The molecules bound to these receptors are taken into the cell through inward folding of the cell surface membrane, which is eventually pinched off into a vesicle within the cell. Structural proteins, such as clathrin, coat the budding vesicle.
Clathrin-Mediated Endocytosis of LDL
One well-characterized example of receptor-mediated endocytosis is the...
The Early Endosome: Endocytosis of Transferrin01:28

The Early Endosome: Endocytosis of Transferrin

Essential proteins such as insulin or low-density lipoprotein (LDL) and micronutrients such as iron enter a eukaryotic cell through receptor-mediated endocytosis. Subsequently, the early endosomes fuse with the vesicles containing such receptor-ligand complexes and play a vital role in sorting the incoming ligands and receptors. While the ligands are either degraded inside the vesicle or released into the cytosol, their receptors are returned to the plasma membrane for further rounds of...
Receptor Downregulation in MVBs01:15

Receptor Downregulation in MVBs

Multivesicular bodies (MVBs) are mature endosomes that sort ubiquitinated proteins and then fuse with lysosomes to degrade the sorted proteins. Epidermal growth factor (EGF) and its receptor (EGFR) form a complex that can be internalized through endocytosis, sorted into an MVB, and later degraded.
The EGFR can initiate signaling pathways that  lead to cell proliferation, migration, and differentiation. Overexpression of EGFR  stimulates cells to proliferate. Excessive  EGFR activation may...
Clathrin Coated Vesicles01:12

Clathrin Coated Vesicles

Clathrin-coated vesicles use endocytosis to transport receptors and lysosomal hydrolases from the Golgi to the lysosome in the late secretory pathway. Clathrin-mediated endocytosis was the first described endocytic process, and Clathrin-coated vesicles remain one of the most well-studied transport vesicles. The molecular machinery that generates clathrin-coated vesicles comprises over 50 proteins that precisely coordinate vesicle formation. Cell surface receptors concentrated in indented sites...
Receptor-Mediated Endocytosis01:20

Receptor-Mediated Endocytosis

Receptor-mediated endocytosis is when bulk amounts of specific molecules are imported into a cell after binding to cell surface receptors. The molecules bound to these receptors are taken into the cell through inward folding of the cell surface membrane, which is eventually pinched off into a vesicle within the cell. Structural proteins, such as clathrin, coat the budding vesicle.
Clathrin-Mediated Endocytosis of LDL
One well-characterized example of receptor-mediated endocytosis is the...