The CatSper channel: a polymodal chemosensor in human sperm
Christoph Brenker1, Normann Goodwin, Ingo Weyand
1Center of Advanced European Studies and Research (caesar), Abteilung Molekulare Neurosensorik, Bonn, Germany.
The EMBO Journal
|February 23, 2012
Summary
Sperm
Area of Science:
- Reproductive Biology
- Ion Channel Physiology
- Sperm Motility
Background:
- The CatSper channel regulates intracellular calcium (Ca2+) in sperm, controlling motility.
- Progesterone and prostaglandins activate CatSper, influencing sperm function.
- Other factors like odorants were thought to signal via G protein-coupled receptors (GPCRs) and cAMP.
Purpose of the Study:
- To investigate the direct mechanism of odorant and cyclic nucleotide analogue activation of CatSper.
- To challenge the prevailing models of sperm Ca2+ signaling pathways.
Main Methods:
- Patch-clamp electrophysiology to record CatSper channel activity.
- Application of various ligands, including odorants and cyclic nucleotide analogues.
- Analysis of Ca2+ influx and sperm swimming behavior.
Main Results:
- Odorants directly activate CatSper channels independently of GPCRs and cAMP.
- Cyclic nucleotide analogues also directly activate CatSper through an extracellular site.
- CatSper exhibits promiscuous binding sites for multiple ligands.
Conclusions:
- Sperm CatSper channels act as direct ionotropic sensors, not solely relying on GPCR/cAMP pathways.
- Ligand-induced Ca2+ signaling in sperm may utilize a common ionotropic mechanism.
- The CatSper complex functions as a polymodal sensor crucial for sperm navigation.
