Modulation of inositol phospholipid metabolism by polyamines

C. D. Smith, R. Snyderman

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

At low concentrations of Mg2+, incorporation of 32P from [γ-32P]ATP into phosphatidylinositol 4-phosphate (PIP) and phosphatidylinositol 4,5-bisphosphate (PIP2) in plasma membranes isolated from human polymorphonuclear leucocytes was enhanced 2-4-fold by the polyamines spermidine and spermine. Polyamines had no effects on inositol phospholipid phosphorylation at high concentrations of Mg2+. At 1 mM-Mg2+, [32P]PIP2 synthesis was maximally enhanced by 2 mM-spermine and 5 mM-spermidine, whereas putrescine only slightly enhanced synthesis. Spermine decreased the EC50 (concn. for half-maximal activity) [32P]PIP or [32P]PIP2 synthesis. Spermine also decreased the EC50 for PI in [32P]PIP synthesis. In contrast, spermine elevated the apparent V(max.), without affecting the EC50 PIP, for [32P]PIP2 synthesis. Spermine and spermidine also inhibited the hydrolysis of [32P]PIP2 by phosphomonoesterase activity. Therefore polyamines appear to activate inositol phospholipid kinases by eliminating the requirements for superphysiological concentrations of Mg2+. Polyamine-mediated inhibition of polyphosphoinositide hydrolysis would serve to potentiate further their abilities to promote the accumulation of polyphosphoinositides in biological systems.

Original languageEnglish (US)
Pages (from-to)125-130
Number of pages6
JournalBiochemical Journal
Volume256
Issue number1
DOIs
StatePublished - 1988

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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