Subsecond modulation of formyl peptide-linked guanine nucleotide- binding proteins by guanosine 5'-O-(3-thio)triphosphate in permeabilized neutrophils

RR Neubig and LA Sklar

Department of Pharmacology, University of Michigan Ann Arbor 48109-0626.

Rapid activation of guanine nucleotide-binding protein (G protein)- mediated signal transduction mechanisms occurs in many tissues. The human neutrophil provides a useful model for studying the mechanisms of these fast processes. Fluorescent chemotactic tetrapeptide and pentapeptide exhibit 30-50% quenching of fluorescence upon binding to the neutrophil formyl peptide receptor, and their binding affinity is strongly regulated by the G protein Gi. We used rapid kinetic spectrofluorometric methods to study the assembly and disassembly of the ternary complex of ligand, receptor, and G protein in digitonin- permeabilized human neutrophils. Binding was studied up to 20 nM ligand, where the half-time for association was 1.2 sec. The rate constant of association was near that for diffusion-limited reactions of ligands and proteins, 2 x 10(7) M-1 sec-1. The rate of uncoupling of formyl peptide receptor from G protein in the presence of high concentrations of guanine nucleotide was > or = 5 sec-1 (i.e., t1/2 of 0.14 sec). Thus, disassembly of the formyl peptide receptor-G protein complex occurs in the millisecond time domain and may be faster than the next step in the signal transduction process.

Volume 43, Issue 5, pp. 734-740, 05/01/1993
Copyright © 1993 by American Society for Pharmacology and Experimental Therapeutics

This article has been cited by other articles:

				J.-Y. Vollmer, P. Alix, A. Chollet, K. Takeda, and J.-L. Galzi Subcellular Compartmentalization of Activation and Desensitization of Responses Mediated by NK2 Neurokinin Receptors J. Biol. Chem., December 31, 1999; 274(53): 37915 - 37922. [Abstract] [Full Text] [PDF]

				C. S. Breivogel, D. E. Selley, and S. R. Childers Cannabinoid Receptor Agonist Efficacy for Stimulating [35S]GTPgamma S Binding to Rat Cerebellar Membranes Correlates with Agonist-induced Decreases in GDP Affinity J. Biol. Chem., July 3, 1998; 273(27): 16865 - 16873. [Abstract] [Full Text] [PDF]

				J. F. Hoffman, J. J. Linderman, and G. M. Omann Receptor Up-regulation, Internalization, and Interconverting Receptor States. CRITICAL COMPONENTS OF A QUANTITATIVE DESCRIPTION OF N-FORMYL PEPTIDE-RECEPTOR DYNAMICS IN THE NEUTROPHIL J. Biol. Chem., August 2, 1996; 271(31): 18394 - 18404. [Abstract] [Full Text] [PDF]

				A. Valenzuela-Fernandez, T. Palanche, A. Amara, A. Magerus, R. Altmeyer, T. Delaunay, J.-L. Virelizier, F. Baleux, J.-L. Galzi, and F. Arenzana-Seisdedos Optimal Inhibition of X4 HIV Isolates by the CXC Chemokine Stromal Cell-derived Factor 1alpha Requires Interaction with Cell Surface Heparan Sulfate Proteoglycans J. Biol. Chem., July 6, 2001; 276(28): 26550 - 26558. [Abstract] [Full Text] [PDF]

				T. Palanche, B. Ilien, S. Zoffmann, M.-P. Reck, B. Bucher, S. J. Edelstein, and J.-L. Galzi The Neurokinin A Receptor Activates Calcium and cAMP Responses through Distinct Conformational States J. Biol. Chem., September 7, 2001; 276(37): 34853 - 34861. [Abstract] [Full Text] [PDF]