Dictyostelium Ric8 is a nonreceptor guanine exchange factor for heterotrimeric G proteins and is important for development and chemotaxis

Kataria, R., Xu, X., Fusetti, F., Keizer-Gunnink, I., Jin, T., van Haastert, P. J. M. & Kortholt, A., 16-Apr-2013, In : Proceedings of the National Academy of Sciences of the United States of America. 110, 16, p. 6424-6429 6 p.

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Heterotrimeric G proteins couple external signals to the activation of intracellular signal transduction pathways. Agonist-stimulated guanine nucleotide exchange activity of G-protein-coupled receptors results in the exchange of G-protein-bound GDP to GTP and the dissociation and activation of the complex into Gα-GTP and a Gβγ dimer. In Dictyostelium, a basal chemotaxis pathway consisting of heterotrimeric and monomeric G proteins is sufficient for chemotaxis. Symmetry breaking and amplification of chemoattractant sensing occurs between heterotrimeric G protein signaling and Ras activation. In a pull-down screen coupled to mass spectrometry, with Gα proteins as bait, we have identified resistant to inhibitors of cholinesterase 8 (Ric8) as a nonreceptor guanine nucleotide exchange factor for Gα-protein. Ric8 is not essential for the initial activation of heterotrimeric G proteins or Ras by uniform chemoattractant; however, it amplifies Gα signaling, which is essential for Ras-mediated symmetry breaking during chemotaxis and development.

Original languageEnglish
Pages (from-to)6424-6429
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number16
Publication statusPublished - 16-Apr-2013


  • Chemotaxis, Dictyostelium, GTP-Binding Proteins, Guanine Nucleotide Exchange Factors, Mass Spectrometry, Microscopy, Confocal, Protozoan Proteins, Receptors, G-Protein-Coupled, Signal Transduction, Video Recording

ID: 14010580