E. Kobrinsky et al., Ceramide triggers intracellular calcium release via the IP3 receptor in Xenopus laevis oocytes, AM J P-CELL, 277(4), 1999, pp. C665-C672
Ceramide, a product of sphingomyelin turnover, is a lipid second messenger
that mediates diverse signaling pathways, including those leading to cell c
ycle arrest and differentiation. The mechanism(s) by which ceramide signals
downstream events have not been fully elucidated. Here we show that, in Xe
nopus laevis oocytes, ceramide-induced maturation is associated with the re
lease of intracellular calcium stores. Ceramide caused a dose-dependent ele
vation in the second messenger inositol 1,4,5-trisphosphate (IP3) via activ
ation of G(q/11)alpha and phospholipase C-beta X Elevation of IP3, in turn,
activated the IP3 receptor calcium release channel on the endoplasmic reti
culum, resulting in a rise in cytoplasmic calcium. Thus our study demonstra
tes that cross talk between the ceramide and phosphoinositide signaling pat
hways modulates intracellular calcium homeostasis.