A bifunctional Gαi/Gαs modulatory peptide that attenuates adenylyl cyclase activity

Christopher A. Johnston, J. Kevin Ramer, Rainer Blaesius, Zoey Fredericks, Val J. Watts, David P. Siderovski

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


Signaling via G-protein coupled receptors is initiated by receptor-catalyzed nucleotide exchange on Gα subunits normally bound to GDP and Gβγ. Activated Gα • GTP then regulates effectors such as adenylyl cyclase. Except for Gβγ, no known regulators bind the adenylyl cyclase-stimulatory subunit Gαs in its GDP-bound state. We recently described a peptide, KB-752, that binds and enhances the nucleotide exchange rate of the adenylyl cyclase-inhibitory subunit Gαi. Herein, we report that KB-752 binds Gαs • GDP yet slows its rate of nucleotide exchange. KB-752 inhibits GTPγS-stimulated adenylyl cyclase activity in cell membranes, reflecting its opposing effects on nucleotide exchange by Gαi and Gαs.

Original languageEnglish
Pages (from-to)5746-5750
Number of pages5
JournalFEBS Letters
Issue number25
StatePublished - 24 Oct 2005


  • Adenylyl cyclase
  • Biosensors
  • G-proteins
  • Phage display
  • Signal transduction
  • Surface plasmon resonance


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