Modulation of cell surface expression of nonactivated cholecystokinin receptors using bivalent ligand-induced internalization

Kaleeckal G. Harikumar, Eyup Akgün, Philip S. Portoghese, Laurence J. Miller

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

CCK2 receptor antagonists potentiate pain relief by MOP receptor agonists. In an attempt to enhance this effect, we prepared bivalent ligands incorporating CCK2 receptor antagonist and MOP receptor agonist pharmacophores.(9)Ligands with 16- to 22-atom spacers could simultaneously bind both receptors but provided no advantage in activity over individual ligands. We now examine the effect of these ligands on receptor internalization as a mechanism of receptor regulation. We prepared CHO cell lines expressing nonfluorescent halves (YN and YC) of yellow fluorescent protein attached to each receptor. Spatial approximation of constructs was needed to yield fluorescence. Monovalent MOP agonist 1 signaled normally and internalized the MOP receptor. Monovalent CCK2 antagonist 2 did not stimulate receptor internalization. In the dual receptor-bearing cells, bivalent ligands 3a-c capable of simultaneously binding both receptors resulted in cell surface fluorescence and internalization of the fluorescent complex in a time- and temperature-dependent manner. Bivalent ligand 4 with spacer too short to occupy both receptors simultaneously yielded no signal. Receptor tethering with appropriate bivalent ligands can down-regulate signaling by moving a nonactivated receptor into the endocytic pathway.

Original languageEnglish (US)
Pages (from-to)2836-2842
Number of pages7
JournalJournal of Medicinal Chemistry
Volume53
Issue number7
DOIs
StatePublished - Apr 8 2010

ASJC Scopus subject areas

  • Molecular Medicine
  • Drug Discovery

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