Identification of kinases, phosphatases, and phosphorylation sites in human and porcine spermatozoa

Abstract

Multiple inter-connected signaling pathways, involving kinases and phosphatases, form a framework that controls sperm motility, function, and fertilizing ability. Methods that give a broad view of the proteomic landscape may prove valuable in uncovering new crosstalk connections, as well as in discovering new proteins within this regulatory framework. A multi-immunoblotting strategy was utilized to evaluate this concept on human and porcine spermatozoa samples. In human and porcine spermatozoa, a diversity of kinases were identified including protein kinase A (PKA), protein kinase B (PKB), isoforms of protein kinase C (PKC), calmodulin-dependent kinases (CAMK), casein kinase (CK), and isoforms of glycogen synthase kinase (GSK3). Several phosphatases, such as protein phosphatase (PP)-1, PP2A, PP2C, and mitogen activated protein kinase (MAPK) phosphatase (MKP-1), were identified in human spermatozoa. The phosphorylation epitopes recognized belonged to members of the MAPK family, in addition to α and β isoforms of GSK3 and cAMP response element binding protein (CREB). Proteomic approaches that allow a broad view may aid in understanding the crosstalk between signaling systems in spermatozoal physiology.

• Kinase
• phosphatase
• phosphorylation
• spermatozoa

Acknowledgments

The authors wish to acknowledge Dr. William Boone for assistance and access to samples and Dr. Donald M. Henricks for guidance and expertise.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Author contribution

Conceived and designed the experiments: BL, SG; Performed the experiments: BL, SG; Analyzed the data: BL,SG; Contributed reagents and materials: SG; Both authors wrote the manuscript and approved the revised paper.

Supplementary material available online