Role of translation by mitochondrial-type ribosomes during sperm capacitation: an analysis based on a proteomic...

Area of Science:

• Reproductive Biology
• Molecular Biology
• Sperm Physiology

Background:

• Mammalian sperm contain mRNAs translated by mitochondrial ribosomes.
• The functions of these sperm mRNAs and their translated proteins remain largely unknown.
• Mitochondrial translation is implicated in sperm function, but specific roles are unclear.

Purpose of the Study:

• To investigate the functional significance of proteins translated by mitochondrial ribosomes during sperm capacitation.
• To identify specific proteins synthesized via mitochondrial translation that are critical for sperm-egg interaction.
• To explore the role of Mups proteins in male fertility and fertilization processes.

Main Methods:

• Differential proteomics using D-chloramphenicol (CP) to inhibit mitochondrial translation.
• Western blot and real-time PCR to validate protein expression.
• Bioinformatics analysis to predict protein functions.
• Immunolocalization and functional assays (antibody depletion) to study Mups proteins.

Main Results:

• 44 proteins showed reduced expression in CP-treated sperm, indicating their synthesis via mitochondrial translation.
• Four proteins were confirmed to be products of mitochondrial translation.
• 26 identified proteins are involved in sperm-egg interaction processes.
• Mups proteins localized to sperm acrosome and flagellum, and their depletion inhibited capacitation, acrosome reaction, and fusion.

Conclusions:

• Mitochondrial translation during sperm capacitation yields proteins vital for successful sperm-egg interaction.
• Mups proteins play a critical role in mammalian fertilization by regulating sperm capacitation and fusion.
• This study highlights the importance of mitochondrial translation in providing essential proteins for male fertility.