Palmitoyltransferase DHHC7 mediates protein palmitoylation and is essential for sperm function through the modulation...

Palmitoylacyltransferase DHHC7 (DHHC7) plays a critical role in various biological processes and diseases. However, its expression, localization, and regulatory mechanisms in sperm function remain largely unknown.

Immunofluorescent staining was used to localize DHHC7 in sperm and examine its colocalization with the estrogen receptor (ER), progesterone receptor (PR), and caveolin-1 (CAV1). To explore DHHC7's role in sperm function, sperm were treated with a specific DHHC7 antibody. Subsequently, sperm motility and motion parameters were analyzed using a computer-assisted sperm analyzer, and the acrosome reaction (an indicator of sperm capacitation) was evaluated using fluorescein isothiocyanate-labeled Pisum sativum agglutinin. To explore the possible regulatory mechanisms of DHHC7 on sperm function, protein palmitoylation was assessed using the acyl-biotin exchange method. Intracellular calcium levels and reactive oxygen species (ROS) production were monitored using fluorescent probes Fluo-4 acetoxymethyl ester (Fluo-4 AM) and 2',7'-Dichlorodihydrofluorescein diacetate (DCFH-DA), respectively, and protein tyrosine phosphorylation levels and DHHC7 protein in sperm were analyzed using Western blotting.

We found that DHHC7 was localized in the neck, principal piece, midpiece, and end piece of sperm in both mice and humans. Treatment with DHHC7 antibodies significantly impaired sperm motility, progressive movement, hyperactivation, and the acrosome reaction under capacitated conditions. Furthermore, DHHC7 colocalized with the ER, PR, and CAV1 in mouse sperm. Additionally, DHHC7 antibodies reduced protein palmitoylation and tyrosine phosphorylation levels, and reduced intracellular calcium elevation and ROS generation during mouse sperm capacitation.

This study identifies DHHC7 as a regulator of sperm motility and capacitation and suggests that its effects involve palmitoylation-dependent modulation of calcium signaling, tyrosine phosphorylation, and ROS signaling by the spatial association with ER, PR, and CAV1. These findings provide novel insights into the biological functions and regulatory mechanisms of DHHC7 in sperm, highlighting its potential significance in reproductive biology.