Receptor-stimulated guanine-nucleotide-triphosphate binding to guanine-nucleotide-binding regulatory proteins : Nucleotide exchange and β-subunit-mediated phosphotransfer reactions
Sylvia KALDENBERG-STASCH; Michael BADEN; Barbara FESSELER; Karl, H. JAKOBS; Thomas WIELAND
Febs Journal 221(1): 25-33
ISSN/ISBN: 1742-464X DOI: 10.1111/j.1432-1033.1994.tb18711.x
In order to study whether phosphate transfer reactions are involved in the binding of guanine nucleotide triphosphates to guanine-nucleotide-binding regulatory proteins, binding of the GTP analogues, guanosine 5'-riphosphate, GTP and guanosine 5'-riphosphate, ppG, and the regulation of binding by the formyl-peptide-receptor agonist, fMet-Leu-Phe, were studied in membranes of differentiated HL-60 cells. For fMet-Leu-Phe-stimulated binding of either GTP analogue, a competing nucleotide was required. With GDP as the competing nucleotide, initial rates of fMet-Leu-Phe-stimulated binding of GTPand ppG were similar for up to approximately 30 s.