Abstract
Binding to the egg's zona pellucida stimulates the spermatozoon to undergo acrosome reaction, a process which enables the sperm to penetrate the egg. Prior to this binding, the spermatozoa undergo in the female reproductive tract a series of biochemical transformations, collectively called capacitation. The first event in capacitation is the elevation of intracellular calcium and bicarbonate to activate adenylyl cyclase (AC) to produce cyclic-AMP, which activates protein kinase A (PKA) to phosphorylate certain proteins. During capacitation, there is also an increase in actin polymerization and in the membrane-bound phospholipase C (PLC). Sperm binding to zona-pellucida causes further activation of cAMP/PKA and protein kinase C (PKC), respectively. PKC opens a calcium channel in the plasma membrane. PKA together with inositol-trisphosphate activate calcium channels in the outer acrosomal membrane, which leads to an increase in cytosolic calcium. The depletion of calcium in the acrosome will activate a store-operated calcium entry mechanism in the plasma membrane, leading to a higher increase in cytosolic calcium, resulting in membrane fusion and acrosome reaction.
Original language | English |
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Pages (from-to) | 139-144 |
Number of pages | 6 |
Journal | Molecular and Cellular Endocrinology |
Volume | 187 |
Issue number | 1-2 |
DOIs | |
State | Published - 22 Feb 2002 |
Bibliographical note
Funding Information:This work was supported by the Israel Science Foundation funded by the Academy of Sciences and Humanities and by Ihel Foundation.
Funding
This work was supported by the Israel Science Foundation funded by the Academy of Sciences and Humanities and by Ihel Foundation.
Funders | Funder number |
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Ihel Foundation | |
Israel Academy of Sciences and Humanities | |
Israel Science Foundation |
Keywords
- Acrosome reaction
- Calcium
- Capacitation
- Regulation
- Sperm