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Fluorimetric Techniques for the Assessment of Sperm Membranes
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SPINK3-Sperm Interaction Determines a Stable Sperm Subpopulation With Intact CatSper Channel
Anabella R Nicolli1, Xiaofang Huang2, Lucia Zalazar1
1Facultad de Ciencias Exactas y Naturales, Instituto de Investigaciones Biológicas (IIB-FCEyN/CONICET), Universidad Nacional de Mar del Plata, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Mar del Plata, Buenos Aires, Argentina.
Journal of Cellular Physiology
|January 22, 2026
Summary
The seminal protease inhibitor SPINK3 prevents premature sperm capacitation by blocking CATSPER1 processing. This action preserves sperm function, highlighting SPINK3
Area of Science:
- Reproductive Biology
- Molecular Endocrinology
- Sperm Physiology
Background:
- Sperm capacitation requires proteolytic remodeling of membrane proteins, including CatSper calcium channels.
- CatSper channels are crucial for sperm hyperactivation and male fertility.
- SPINK3 is a known decapacitation factor that inhibits premature capacitation.
Purpose of the Study:
- To identify the physiological inhibitor of CATSPER1 processing during sperm capacitation.
- To elucidate the role of SPINK3 in regulating CatSper channel function and sperm capacitation.
Main Methods:
- Investigated SPINK3's inhibitory effect on CATSPER1 cleavage in mouse sperm.
- Analyzed the localization and membrane effects of SPINK3.
- Assessed the impact of SPINK3 on sperm capacitation markers like pTyr development and cholesterol efflux.
Main Results:
- SPINK3 was identified as the first physiological inhibitor of CATSPER1 processing.
- SPINK3 blocks capacitation-induced CATSPER1 cleavage, maintaining a subpopulation of sperm with intact CatSper channels.
- SPINK3 stabilizes sperm membrane organization and delays cholesterol efflux, localizing to the principal piece membrane.
Conclusions:
- SPINK3 is a multifunctional regulator of sperm capacitation.
- SPINK3 plays a critical role in shaping sperm subpopulations within the female reproductive tract.
- SPINK3's inhibition of CATSPER1 processing is key to preserving sperm function and fertility.
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