H. Haag et al., LOVASTATIN INHIBITS RECEPTOR-STIMULATED CA2-INFLUX IN RETINOIC ACID DIFFERENTIATED U937 AND HL-60 CELLS(), Cellular signalling, 6(7), 1994, pp. 735-742
Lovastatin was used to study the role of isoprenylated proteins on sti
mulus-induced increase of cytosolic Ca2+ in retinoic acid-differentiat
ed U937 and HL-60 cells. Preincubation of the cells with lovastatin fo
r 11-24 h reduced the Ca2+-influx induced by PAF of FMLP. The maximal
decrease was 60% in U937 cells and 40% in HL-60 cells. The ID50s of lo
vastatin in U937 and HL-60 cells were 5 mu M and 15 mu M, respectively
. Lovastatin did not inhibit Ca2+-discharge from intracellular stores.
Addition of mevalonate to lovastatin-treated cells completely reverse
d the inhibition of PAF- and FMLP-stimulated Ca2+-mobilization. Immuno
reactivity of ras-like proteins was decreased in membranes and increas
ed in the cytosol of U937 cells by 1 day treatment with lovastatin. We
conclude that isoprenylated proteins are involved in the regulation o
f receptor-stimulated Ca2+-entry of differentiated HL-60 and U937 cell
s.