Ca2+-dependence of arachidonic acid redistribution among phospholipids of cultured mouse keratinocytes

Laura Pacini, Angelo Spinedi, Mauro Piacentini, Cristina Limatola, Maria Grazia Farrace, Francesco Autuori, Paolo Luly

Research output: Contribution to journalArticle

Abstract

Mouse keratinocytes cultured in a medium containing less than 0.1 mM Ca2+ (low Ca2+) incorporated [1-l4C]arachidonic acid (AA) into phospholipids by kinetics including; (i) a rapid labelling of phosphatidylinositol (PtdIns), phosphatidylserine (PtdSer) and both acid-stable and alkenylacyl forms of phosphatidylcholine (PtdCho); and (ii) a slow but long-lasting radiolabel incorporation into both acid-stable and alkenylacyl forms of phosphatidylethanolamine (PtdEtn), partly associated with a net radioactivity loss from acid stable-PtdCho. Under low Ca2+ conditions no radioactivity transfer apparently occurred between PtdIns and other phospholipid classes. When cells were prelabelled for 24 h with [1-14C]AA and reincubated in label-free medium containing 1.2 mM Ca2+ (normal Ca2+), an early and extensive loss of radioactivity from PtdIns was observed, reasonably in connection with Ca2+ stimulation of phosphoinositide turnover [1]. Cell shift to normal Ca2+ did not result in an increased synthesis of labelled eicosanoids, but was consistent with an increase of radioactivity incorporation into diacylglycerol (DAG) and with a complex pattern of [1-14C]AA redistribution, eventually leading to a marked radioactivity incorporation into acid stable-PtdEtn (but not into alkenylacyl-PtdEtn) and to a labelling decrease of acid stable-PtdCho. The possible mechanisms driving AA recycling after cell shift to normal Ca2+ are discussed.

Original languageEnglish
Pages (from-to)213-218
Number of pages6
JournalBiochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism
Volume1045
Issue number3
DOIs
Publication statusPublished - Aug 6 1990

Keywords

  • (Mouse)
  • Arachidonic acid
  • Calcium
  • Keratinocyte
  • Phospholipid

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Endocrinology

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