Characterization of a plasma membrane-associated prenylcysteine-directed α carboxyl methyltransferase in human neutrophils

Michael H. Pillinger, Craig Volker, Jeffry B. Stock, Gerald Weissmann, Mark R. Philips

Research output: Contribution to journalArticle

60 Scopus citations

Abstract

Signal transduction in human neutrophils requires prenylcysteine-directed carboxyl methylation of ras-related low molecular weight GTP-binding proteins. We now report the subcellular localization and characterization of a neutrophil prenylcysteine α carboxyl methyltransferase. The highest carboxyl methyltransferase activity copurified with biotinylated neutrophil surface membranes, supporting a plasma membrane localization of the enzyme. Neutrophil nuclear fractions contained little or no methyltransferase activity. Methyltransferase activity was detergent-sensitive but could be reconstituted by removal of detergent in the presence of phosphatidyl choline and an anionic phospholipid. N-Acetyl-S-trans,trans-farnesyl-L-cysteine (AFC) and N-acetyl-S-all-trans-geranylgeranyl-L-cysteine (AGGC) were effective substrates for neutrophil prenylcysteine-directed methyltransferase; V(max) values for AFC and AGGC (16.4 and 22.1 pmol of methylated/mg protein/min, respectively) are among the highest yet reported. Although both GTPγS and the chemoattractant fMet-Leu-Phe stimulated methylation of ras-related proteins, neither affected methylation of AFC. These data suggest that neutrophil plasma membranes contain a phospholipid-dependent, prenylcysteine- directed carboxyl methyltransferase of relatively high specific activity that modifies ras-related protein substrates in the GTP-bound, activated state.

Original languageEnglish (US)
Pages (from-to)1486-1492
Number of pages7
JournalJournal of Biological Chemistry
Volume269
Issue number2
StatePublished - Jan 14 1994

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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