International Journal of Molecular Sciences Article Bull Sperm Capacitation Is Accompanied by Redox Modifications of Proteins Agnieszka Mostek *, Anna Janta , Anna Majewska and Andrzej Ciereszko Department of Gamete and Embryo Biology, Institute of Animal Reproduction and Food Research of Polish Academy of Sciences, 10-748 Olsztyn, Poland;
[email protected] (A.J.);
[email protected] (A.M.);
[email protected] (A.C.) * Correspondence:
[email protected]; Tel.: +48-89-5393134 Abstract: The ability to fertilise an egg is acquired by the mammalian sperm during the complex biochemical process called capacitation. Capacitation is accompanied by the production of reactive oxygen species (ROS), but the mechanism of redox regulation during capacitation has not been elucidated. This study aimed to verify whether capacitation coincides with reversible oxidative post-translational modifications of proteins (oxPTMs). Flow cytometry, fluorescence microscopy and Western blot analyses were used to verify the sperm capacitation process. A fluorescent gel-based redox proteomic approach allowed us to observe changes in the level of reversible oxPTMs manifested by the reduction or oxidation of susceptible cysteines in sperm proteins. Sperm capacitation was accompanied with redox modifications of 48 protein spots corresponding to 22 proteins involved in the production of ROS (SOD, DLD), playing a role in downstream redox signal transfer (GAPDHS and GST) related to the cAMP/PKA pathway (ROPN1L, SPA17), acrosome exocytosis (ACRB, sperm acrosome associated protein 9, IZUMO4), actin polymerisation (CAPZB) and hyperactivation Citation: Mostek, A.; Janta, A.; (TUBB4B, TUB1A). The results demonstrated that sperm capacitation is accompanied by altered Majewska, A.; Ciereszko, A.