G protein-coupled receptor desensitization as a measure of signaling: modeling of arrestin recruitment to activated CCK-B receptors

Assay Drug Dev Technol. 2003 Jun;1(3):409-24. doi: 10.1089/154065803322163722.


Gastrin is one of the principle hormonal mediators of gastric acid secretion, and its cognate receptor (CCK-B) is a member of the superfamily of GPCRs. Patients with hypergastrinemia may present with a variety of symptoms, including gastric ulcers or malignant tumors. Thus, the molecular mechanisms that terminate CCK-B receptor signaling, as well as an ability to measure gastrin bioactivity in a timely manner, have important clinical implications. In order to assess CCK-B receptor regulation, we have constructed a single cell biosensor containing the CCK-B receptor and an arrestin/GFP chimera. The gastrin biosensor responded to both immunologically detectable gastrin-17 and undetectable pentagastrin, and was able to determine the gastrin bioactivity of serum from a patient with clinical hypergastrinemia. We determined that the CCK-B receptor binds arrestin with a pharmacology mirroring CCK-B receptor signaling through inositol phosphate, and that the rate of arrestin dissociation from internalized receptor mirrors receptor recycling to the plasma membrane. Moreover, the CCK-B recycling rate is intermediate between that of Class A GPCRs such as the beta2-adrenergic receptor and Class B GPCRs such as the vasopressin type 2 receptor. Mathematical modeling of these results indicates that a common receptor conformation may underlie both CCK-B signaling and desensitization. In addition to its use in drug screening, this methodology should generalize to other receptors for use in diagnosis and monitoring of bioactive ligands involved in GPCR-based disease.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Arrestin / metabolism*
  • Arrestins / metabolism
  • Biosensing Techniques
  • Cell Line
  • Gastrins / metabolism
  • Humans
  • Inositol / metabolism
  • Kinetics
  • Microscopy, Fluorescence
  • Pentagastrin / metabolism
  • Protein Binding
  • Receptor, Cholecystokinin B / metabolism*
  • Signal Transduction / physiology*
  • Transfection
  • beta-Arrestins


  • Arrestin
  • Arrestins
  • Gastrins
  • Receptor, Cholecystokinin B
  • beta-Arrestins
  • Inositol
  • gastrin 17
  • Pentagastrin