- Title
- A cytosolic sperm protein factor mobilizes Ca²⁺ from intracellular stores by activating multiple Ca²⁺ release mechanisms independently of low molecular weight messengers
- Creator
- Galione, Antony; Jones, Keith T.; Laii, F. Anthony; Swann, Karl
- Relation
- Journal of Biological Chemistry Vol. 14, Issue 46, p. 28901-28905
- Publisher Link
- http://dx.doi.org/10.1074/jbc.272.46.28901
- Publisher
- Walter de Gruyter GmbH & Co. KG
- Resource Type
- journal article
- Date
- 1997
- Description
- Ca²⁺ oscillations can be induced in mammalian eggs and somatic cells by microinjection of a cytosolic sperm protein factor. The nature of the sperm factor-induced Ca²⁺ signaling was investigated by adding sperm protein extracts to homogenates of sea urchin eggs, which contain multiple classes of Ca²⁺ release mechanisms. We show that the sperm factor mobilizes Ca²⁺ from non-mitochondrial Ca²⁺ stores in egg homogenates after a distinct latency. This latency is abolished by preincubation of sperm extracts with egg cytosol. The preincubation step is highly temperature-dependent and generates a high molecular weight, protein-based Ca²⁺-releasing agent that can also mobilize Ca2+ from purified egg microsomes. This Ca²⁺ release appears to be mediated via both inositol 1,4,5-trisphosphate and ryanodine receptors, since homologous desensitization of these two release mechanisms by their respective agonists inhibits further release by the sperm factor. However, sperm factor-induced Ca²⁺ release by these channels is independent of inositol 1,4,5-trisphosphate or cADPR since antagonists of either of these two messengers did not block the Ca²⁺ release effected by the sperm factor. The sperm protein factor may cause Ca²⁺ release via an enzymatic step that generates a protein-based Ca²⁺-releasing agent.
- Subject
- protein; egg; cytosolic; molecular; oscillations; sperm; intracellular; Ca²⁺
- Identifier
- uon:6596
- Identifier
- http://hdl.handle.net/1959.13/804352
- Identifier
- ISSN:1431-6730
- Language
- eng
- Full Text
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