TY - JOUR
T1 - Activation-dependent carboxyl methylation of neutrophil G-protein γ subunit
AU - Philips, M. R.
AU - Staud, R.
AU - Pillinger, M.
AU - Feoktistov, A.
AU - Volker, C.
AU - Stock, J. B.
AU - Weissmann, G.
PY - 1995
Y1 - 1995
N2 - The γ subunits of heterotrimeric guanine nucleotide-binding regulatory (G) proteins (G(γ)) are post-translationally processed at their C termini by prenylation, proteolysis, and carboxyl methylation. Whereas prenylation of G(γ), is required for membrane association of G proteins, the role of carboxyl methylation is unknown. Here we show that human neutrophils express G(γ2) but not G(γ3) or G(γ7) and that carboxyl methylation of G(γ2) is associated with signal transduction. In a reconstituted cell-free system, neutrophil was labeled by the methyl donor S-[methyl-3H]adenosyl-L- methionine. Carboxyl methylation was confirmed by alkaline hydrolysis and quantitation of volatile [3H]methanol. Neutrophil G(γ2) methylation was stimulated by activation of G protein with guanosine 5'-[β,γ- thio]triphosphate. We estimate that after 1 hr of G-protein activation at least 6% of the total pool of G(γ2) was carboxyl-methylated. The inflammatory agonist fMet-Leu-Phe stimulated guanosine 5'-[β,γ- thio]triphosphate-dependent carboxyl methylation. Methylation of G(γ2) was inhibited by the carboxyl methyltransferase inhibitor N-acetyl-S- trans,trans-farnesylcysteine at concentrations that affected signal transduction in neutrophils. These results demonstrate that activation of neutrophil G(i) is associated with α-carboxyl methyl esterification of G(γ2) and suggest that carboxyl methylation of G(γ) may play a role in signal transduction.
AB - The γ subunits of heterotrimeric guanine nucleotide-binding regulatory (G) proteins (G(γ)) are post-translationally processed at their C termini by prenylation, proteolysis, and carboxyl methylation. Whereas prenylation of G(γ), is required for membrane association of G proteins, the role of carboxyl methylation is unknown. Here we show that human neutrophils express G(γ2) but not G(γ3) or G(γ7) and that carboxyl methylation of G(γ2) is associated with signal transduction. In a reconstituted cell-free system, neutrophil was labeled by the methyl donor S-[methyl-3H]adenosyl-L- methionine. Carboxyl methylation was confirmed by alkaline hydrolysis and quantitation of volatile [3H]methanol. Neutrophil G(γ2) methylation was stimulated by activation of G protein with guanosine 5'-[β,γ- thio]triphosphate. We estimate that after 1 hr of G-protein activation at least 6% of the total pool of G(γ2) was carboxyl-methylated. The inflammatory agonist fMet-Leu-Phe stimulated guanosine 5'-[β,γ- thio]triphosphate-dependent carboxyl methylation. Methylation of G(γ2) was inhibited by the carboxyl methyltransferase inhibitor N-acetyl-S- trans,trans-farnesylcysteine at concentrations that affected signal transduction in neutrophils. These results demonstrate that activation of neutrophil G(i) is associated with α-carboxyl methyl esterification of G(γ2) and suggest that carboxyl methylation of G(γ) may play a role in signal transduction.
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U2 - 10.1073/pnas.92.6.2283
DO - 10.1073/pnas.92.6.2283
M3 - Article
C2 - 7892262
AN - SCOPUS:0028964316
SN - 0027-8424
VL - 92
SP - 2283
EP - 2287
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 6
ER -