A mammalian sperm cytosolic phospholipase C activity generates inositol trisphosphate and causes Ca2+ release in sea urchin egg homogenates

• Published in: FEBS letters Vol. 437; no. 3; pp. 297 - 300
• Main Authors: Jones, Keith T, Cruttwell, Caroline, Parrington, John, Swann, Karl
• Format: Journal Article
• Language: English
• Published: England 23.10.1998
• Subjects: Animals; bsf, boar sperm factor; cADPR, cyclic ADPRibose; Calcium; Calcium - metabolism; Calcium Channels - metabolism; Cytosol - enzymology; Egg; Enzyme Activation; IM, intracellular medium; Inositol 1,4,5-Trisphosphate - biosynthesis; Inositol 1,4,5-Trisphosphate Receptors; Inositol trisphosphate; InsP3, inositol 1,4,5-trisphosphate; InsP3R, InsP3 receptor; Male; NAADP, nicotinic acid adenine dinucleotide phosphate; Oocytes - enzymology; Phospholipase C; PI, phosphatidylinositol; PI-PLC, PI-specific PLC; PIP2, phosphatidyl inositol 4,5-bisphosphate; PIP2-PLC, PIP2 specific PLC; PLC, phospholipase C; Receptors, Cytoplasmic and Nuclear - metabolism; RyR, ryanodine receptor; Sea Urchins; Sperm; Spermatozoa - enzymology; Swine; Type C Phospholipases - metabolism
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(98)01254-X

Injection of sperm extracts triggers Ca2+ oscillations in mammalian eggs similar to those seen at fertilisation. Here, we show that addition of sperm extracts to sea urchin egg homogenates causes Ca2+ release and inositol 1,4,5‐trisphosphate (InsP3) production. Furthermore depleting homogenates of phosphatidylinositol lipids using a phosphatidylinositol‐specific phospholipase C blocked the sperm extract from causing InsP3 production and a Ca2+ rise. A response could be recovered by the addition of phosphatidylinositol 4,5‐bisphosphate to either sperm extracts or egg homogenates. These data indicate that sperm extracts contain an InsP3‐generating phospholipase C which may play a role in Ca2+ release at fertilisation.