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Phosphopeptide Analysis of Rodent Epididymal Spermatozoa
Published on: December 30, 2014
Mouse sperm K+ currents stimulated by pH and cAMP possibly coded by Slo3 channels
Pablo Martínez-López1, Celia M Santi, Claudia L Treviño
1Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), 62210 Cuernavaca, Morelos, Mexico.
Biochemical and Biophysical Research Communications
|April 3, 2009
Summary
High conductance Slo3 potassium channels in mammalian sperm are activated by intracellular alkalinization and cAMP. These findings suggest Slo3 channels are crucial for sperm function and fertilization.
Area of Science:
- Ion channel physiology
- Sperm biology
- Molecular and cellular biology
Background:
- Slo3 channels are high-conductance potassium channels found exclusively in mammalian sperm.
- These channels are known activators of voltage and intracellular alkalinization.
- Sperm capacitation, essential for fertilization, involves intracellular alkalinization and increased cAMP levels.
Purpose of the Study:
- To investigate the role and properties of Slo3 channels in mammalian sperm.
- To determine the effect of cAMP on Slo3 channel activity.
- To confirm if the native potassium current in sperm is mediated by Slo3 channels.
Main Methods:
- Heterologous expression of Slo3 channels in Xenopus oocytes.
- Patch-clamp recordings from mouse sperm.
- Analysis of ion channel properties including voltage/time dependence, ion selectivity, and drug sensitivity.
Main Results:
- Slo3 channels expressed in oocytes are stimulated by elevated cAMP via PKA-dependent phosphorylation.
- A native K+ current in mouse sperm exhibits properties matching heterologously expressed Slo3 channels.
- This sperm K+ current is time/voltage-dependent, activated by alkalinization, has a high PK/PNa ratio, and is stimulated by cAMP.
Conclusions:
- The native potassium current observed in mammalian sperm is carried by Slo3 channels.
- Slo3 channel activity is modulated by both intracellular alkalinization and cAMP.
- These findings highlight the critical role of Slo3 channels in sperm function and capacitation.
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