Mouse keratinocytes cultured in a medium containing less than 0.1 mM Ca2+ (low Ca2+) incorporated [1-14C]arachidonic acid (AA) into phospholipids by kinetics including; (i) a rapid labelling of phosphatidylinositol (PtdIns), phosphatidylserine (PdtSer) 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. 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.
Pacini, L., Spinedi, A., Piacentini, M., Limatola, C., Farrace, M.g., Autuori, F., et al. (1990). Ca2+-dependence of arachidonic acid redistribution among phospholipids of cultured mouse keratinocytes. BIOCHIMICA ET BIOPHYSICA ACTA, 1045(3), 213-218 [10.1016/0005-2760(90)90122-E].
Ca2+-dependence of arachidonic acid redistribution among phospholipids of cultured mouse keratinocytes
SPINEDI, ANGELO;PIACENTINI, MAURO;FARRACE, MARIA GRAZIA;AUTUORI, FRANCESCO;LULY, PAOLO
1990-01-01
Abstract
Mouse keratinocytes cultured in a medium containing less than 0.1 mM Ca2+ (low Ca2+) incorporated [1-14C]arachidonic acid (AA) into phospholipids by kinetics including; (i) a rapid labelling of phosphatidylinositol (PtdIns), phosphatidylserine (PdtSer) 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. 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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.