Original Paper

Identification of Peptides That Inhibit Regulator of G Protein Signaling 4 Function
Yuren Wang, Yan Lee, Jie Zhang, Kathleen H. Young

Neuroscience Discovery Research, Wyeth Research, Princeton, N.J., USA

Address of Corresponding Author

Pharmacology 2008;82:97-104 (DOI: 10.1159/000138387)

  Key Words

• Regulator of G protein signaling 4
• GTPase-activating protein
• G proteins
• Yeast two-hybrid system

  Abstract

Regulators of G protein signaling (RGS) are a family of GTPase-activating proteins (GAP) that interact with heterotrimeric G proteins in the negative regulation of G-protein-coupled receptor (GPCR) signaling. RGS4, the first identified mammalian member of the RGS family, has been implicated in many GPCR signaling pathways involved in disease states. We report herein the identification of a 16-amino-acid peptide (P17) as an inhibitor of RGS4. The peptide was found by screening a random peptide library using RGS4 as 'bait' in a yeast two-hybrid system. This peptide inhibited RGS4 GAP activity on G_i1 in a GTPase assay, and blocked the interaction between RGS4 and G_i1 in a pull-down assay. The peptide displayed dose-dependent inhibition of RGS4 and G-interacting protein (GAIP) GAP activities, yet showed no substantial effect on RGS7. Electrophysiological studies in Xenopus oocytes demonstrated that P17 attenuates RGS4 modulation of M₂ muscarinic receptor stimulation of GIRK (G-protein-mediated inwardly rectifying potassium) channels. Deletion of an arginine at the N terminus of P17 abolished its ability to inhibit RGS4 GAP activity, as did deletions of C-terminal residues. The P17 peptide showed no similarity to any known peptide sequence. Further investigation and optimization of the peptide may provide unique information for the development of RGS4 inhibitors for future therapeutic application.

Copyright © 2008 S. Karger AG, Basel

  Author Contacts

Jie Zhang
Wyeth Research
Princeton, NJ 08543-8000 (USA)
Tel. +1 732 274 4111, Fax +1 732 274 4020
E-Mail zhangj7@wyeth.com

  Article Information

Received: February 1, 2008
Accepted: February 14, 2008
Published online: June 12, 2008
Number of Print Pages : 8
Number of Figures : 4, Number of Tables : 1, Number of References : 25