Vol. 277, Issue 4, C665-C672, October 1999
Ceramide triggers intracellular calcium release via the
IP3 receptor in
Xenopus laevis
oocytes
Evgeny
Kobrinsky1,
Andrew I.
Spielman2,
Sophia
Rosenzweig2, and
Andrew R.
Marks1
1 Molecular Cardiology Program,
Divisions of Cardiology and Circulatory Physiology, Departments of
Medicine and Pharmacology, Columbia University College of
Physicians and Surgeons, New York 10032; and
2 New York University College of
Dentistry, Basic Science Division, New York, New York
10010
Ceramide, a product of sphingomyelin turnover, is a lipid second
messenger that mediates diverse signaling pathways, including those
leading to cell cycle arrest and differentiation. The mechanism(s) by
which ceramide signals downstream events have not been fully elucidated. Here we show that, in Xenopus
laevis oocytes, ceramide-induced maturation is
associated with the release of intracellular calcium stores. Ceramide
caused a dose-dependent elevation in the second messenger inositol
1,4,5-trisphosphate (IP3) via
activation of Gq/11
and
phospholipase C-
X. Elevation of
IP3, in turn, activated the
IP3 receptor calcium release
channel on the endoplasmic reticulum, resulting in a rise in
cytoplasmic calcium. Thus our study demonstrates that cross talk
between the ceramide and phosphoinositide signaling pathways modulates
intracellular calcium homeostasis.
meiotic maturation; calcium signaling; phospholipase C
